Printer Table: Started and Finished

I finished this project in months instead of years. It’s like I blinked and had a finished project! It went went together so fast it was done and in service before I thought to take pictures.

I wanted to build a table to hold the printer and its various supplies. I also wanted to get some electronics equipment off the floor and tidy things up. So I planned a table using the Festool Domino. It was meant to be a quick project. I had purchased some sapele before the pandemic for the project: a one inch thick board for the top and a two inch thick board for legs. I started by joining the top together with the “dominoes” which are small wooden rectangles that go into the mortise on each side of the joint. The dominoes for a tabletop are just meant to help with alignment, but I must have jiggled the machine because my slots ended up misaligned, so I left many of the mortises I cut empty. The completed sapele top looks like this.

Sapele table top glued up from three boards. The sapele stripe figure hides the board joints quite well.

I cut the legs from the two inch thick wood and then sawed the remaining wood thinner to use for aprons.
I wanted to make the table rigid so it wouldn’t shake while the printer was working, so I made the aprons as tall as the board allowed, and cut out a curve on the front for a more graceful and less blocky appearance.

The apron is very tall but the curve prevents the cabinet from looking heavy. The curve also makes the storage space more usable. Each shelf has a mixture of different woods.

For shelves I drilled holes in the four legs for shelf pins. To make the shelves I used random stock from my wood pile: some cherry, some canary wood, and some mahogany. I lined the front and back of the shelves with sapele pieces so the shelves would look the same from the front. The sapele edge pieces also stick down outside the shelf pins, so they hold the shelves in place on the pins. This turned out to be a great way to get rid of wood scraps that were languishing in my wood pile. Once the shelves are loaded up, only the front is visible, so the mix of woods makes no difference.

I made one design error: the table is a little bit too deep. I made it to line up with the cabinet to the left, but I forgot that there needs to be clearance for that cabinet’s door to open. I had to shift the left-side cabinet forward away from the wall by 3/4 inch so the door wouldn’t crunch against the table top when opened, and this creates a problem of being able to lose things behind the cabinet.

Removing the equipment from the bottom shelf is a lot of trouble, so the wood used there is a secret.

Here it is loaded with the printer and paper.

My next project is a new dining table, and at this point I don’t have a design, just vague ideas. I also don’t have any wood. I think that project is going to take longer.

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Bedroom Chest: Finished

The bedroom chest is finally finished. I seem to say that about every project. My first post was in January of 2017, so it took five years. This is the first time I made frame and panel doors, or sliding doors.

I made the cabinet out of maple: quarter sawn hard maple for the case and frames, and spalted quilted maple for the door fronts. Notice how it seems to float above the floor?

We need to be able to move the cabinet easily for changing the bed, so it’s on wheels. The front wheels hide behind the apron. The rear wheels are exposed at the back so we can flip the wheel brakes on and off.

The interior has holes for shelf pins: two columns on each side, and one right down the center of the back. It turns out, the back, which I made for 1/2″ plywood, was not thick enough, and when I drilled the holes for the shelf pin sleeves, it created a series of holes in the plywood.

To cover the holes I added a strip down the center of the back, making it look as if the back is made from two panels. I had originally had a naive idea that I could cut the plywood to fit exactly the the rabbet at the back. When faced with reality I covered the gap between the back and the case using a tiny strip of cherry wood, which creates a nice framed look. It’s looks much better with that divider in the center, so evidently the problem created by the shelf pins was a good thing.

The top features a backsplash to keep stuff off the bed, and I thought it would be interesting to make a smooth transition between the top and backsplash, which I did by applying an extra strip and planing it down. I think this technique worked quite well.

Left drawer closeup.

Center drawers.

Right hand drawer.

Here are the little drawers pulled out, showing their red oak solid wood drawer bottoms.

On my game table I used handles with a bevel on the underside. For this piece I thought the drawers might need a handle that is less effort to pull. After some experimentation I settled on this rabbet handle design, which is very easy to grip with just fingertips. Here you can see the spalt lines running through the end grain of the handle.

For the small handles, the shape is similar, but a little more angled to provide more room for the fingers in a handle that sticks out less from the drawer front.

The right hand drawer handle.

Left hand drawer handle close up.

Right hand drawer handle close up. These handles came from the same board, just a few inches apart!

The joinery on a large drawer features a funny looking half-tail at the bottom. This allowed me to get the drawer bottom lower in the drawer. But this half-tail is harder to cut than a regular joint. It’s more visible from the bottom of the drawer as well.

Here’s the drawer bottom, made of ash. The drawer sides for this project were cherry and the bottoms ash and oak, all made from wood I had lying around the shop.

Here are the dovetails on the small drawers. The spalting in the pin is interesting. The drawers are all side hung. Side hung drawers turn out to be nightmarishly difficult to install. The rails need to be perfectly parallel and the same height. I drilled and filled the screw holes for those side rails many times. This has made me wonder whether some of the difficulties I’ve had with metal drawer slides aren’t because they are metal, but because they are side mounted. The drawers do not move as nicely as the bottom mounted or box-in-a-hole type drawers I used on the game table.

I made the sliding door with a rabbet on the bottom. The weight of the door rests on the rabbet, not on the part of the door that fits into the track. The door does not touch the bottom of the track, so dust and crud in the track should not have much effect on the door’s movement. The need to cut this rabbet is one of the reasons I constructed the doors with rails (horizontal parts of the frame) running the full width instead of the more conventional manner, where the stiles (vertical parts of the frame) run the full height. The sliding doors move easily with a single finger in their hexagonal pulls.

The hexagonal finger pulls were tricky to cut, and I was lucky I had a scrap of the material from the door panels left to use as backers for the holes.

The underside was never meant to be seen, but someone asked about how the wheels and skirt were constructed, so here’s an ugly shot from underneath showing the hidden wheels and the skirt (and secret dovetails). I made the skirt by gluing the front piece onto the cabinet and then gluing the side pieces on just at the front, and using screws through oval holes at the back to allow for wood movement.

Bedroom Chest: Drawers

I had special wood selected for the drawer fronts, but before I could start work I needed to select material for the drawer sides. I hunted through my lumber pile and found some cherry that seemed like it might work. It was lumber I originally mail ordered for the file cabinet 20 years ago that was warped. By the time I got the boards flat it was about the right thickness for drawers.  I think it’s a little funny that I have cherry as the secondary wood on drawers: I suspect it’s not very common. 

The next step was to cut the grooves for the drawer bottom and the side rail. The drawer bottom groove (not shown) was easy to cut using my plow plain, but the side rail groove was more troublesome because it was in the middle of the board.  The plow plane fence doesn’t reach, and if it did it seems like it would be awkward.  I cut it using my dado plane.

Cutting the groove for a side hung drawer using a dado plane.

Once the grooves were cut, the dovetailing could begin. I used the “blue tape trick”. I wonder how many so-named tricks exist. I know two for dovetails. This trick is a variation on the rabbet trick for dovetail alignment. Instead of cutting a rabbet you lay down blue tape on the tailboard. You do it carelessly so the tape covers over the gauge line. Then you use your marking gauge to cut away the tape at the gauge line, and this gives a tiny little edge from the tape, which is remarkably effective at aligning the tailboard onto the pinboard for marking. You can simply press the tailboard up against the pin board and get it perfectly aligned. This was definitely the easiest scheme I’ve ever used for performing the marking.

Blue tape on the tailboards for execution of the blue trick for marking the pinboard from the tailboard.

On to the dovetailing. I laid out the dovetails so that the pin on the drawer front (top in the picture) blocks the slot cut on the side. This creates an elegant built-in drawer stop. After laying out the front I transferred the layout to the back as well, and then cut the joint on all four corners of the two large drawers. Only after I had the tails all cut did I realize the problem.

It’s going to be hard to slide this drawer onto its side rail.

Because I unthinkingly transferred the marks from the front to the back the drawer has a “stop” at both ends, which means it will be impossible to slide it onto the side rail. Oops. I had to cut out the pin at the back end. I sawed the sides and tried cutting with a chisel, but could not avoid a lot of tearing out of the wood. My second attempt using the router plane was slower, but produced a better result.

Cutting out the tail using a chisel produces a terrible surface on the end grain.

Using the router plane to do the job gives a much better result.

I didn’t make the same mistake on the small drawers. I laid out the back joint separately. I tried making the pins as narrow as possible. I didn’t find the narrow pins to be any more difficult to cut that larger pins, though I did find that I really needed to use my thin bladed Veritas chisel, which seems to be a discontinued item. I wonder if anybody else sells a chisel with a thin blade like this.

Normal 1/2″ chisel at the top. The Veritas thin chisel at the bottom.

Small drawers, front dovetails, with fat pins.

Small drawers, with thin pins.

After the drawers were finished I found that the biggest ordeal was mounting the side rails so that the drawers would move well and were located in the right position as viewed from the front. Very slight changes in the rails would change the gaps around the drawers. I drilled and filled the mounting holes many times before getting a result that seemed acceptable. I’m not inclined to make side hung drawers again. Here’s an example of a crooked gap, where the space between the two drawers is visibly much smaller on the left than on the right.

Uneven gap between the top and bottom drawers.

Here are the little drawers in their final configuration (after more filling and drilling).

The two center drawers in their final configuration.

I felt like I had created too much vertical space for these drawers. I’m never quite sure how much space I need, but the shop is a humid environment, so the drawers will probably shrink, making the gaps even bigger.

Cabinet with all of the drawers inserted.

The project is nearly done. All that remains to be done is the installation of the back, the shelf pin holes, and the finishing of the case. The drawers are already finished, and I do wonder if the large drawers are going to look odd because they are so light. I used shellac on the drawers and door panels but Polyx on the door frames. The Polyx evidently darkens the maple more than the shellac, because the panel rails are the same wood as the much lighter drawer fronts.

Bedroom Chest: Handles and Pulls

I have completed the cabinet case and finished the cabinet’s top. The next step is to make the drawers, which raises some unresolved design questions: what will the drawer pulls look like and what wood will I use for the center drawers. My original thinking was that I might cut pulls into the faces of the drawers so they wouldn’t obscure the flecking in the quartersawn maple. The sliding doors need inset handles because a projecting handle on the rear door would slam into the front door, so inset draw pulls could help unify the design. Our bedside tables feature such inset pulls, but I do not know how they were cut. To do it with a router would require an extremely long bit, extending very far away from the tool. Maybe a CNC can cut handles like this.

I have seen hand-carved drawer pulls at the Wharton Esherick House so I attempted a carved pull.  The result was functional and I think I could produce a decent looking pull, but I seriously question my capacity to produce two pulls that match.   So I considered a different approach:  I cut out an angled slot with a framesaw and glued a small wood scrap behind. This method also produced a functional pull.   But I didn’t like the look of it.  And this exercise lead me to discover something that should have been obvious: the angled cuts cause the quartersawn fleck pattern to disappear, so the inset handle doesn’t preserve the interesting grain pattern featured on the drawer fronts.

Handle testing: At the top of the board I carved a handle with gouges. At the bottom of the board I cut out a handle with a saw and glued on a backer board. Note that the quartersawn fleck disappears with the angled cut of the handle.

Handles for Sliding Doors

For the sliding doors, cutting inset handles is simpler: because they are used to move the doors sideways without any pulling, they do not need to be angled to the face of the door.   My first idea was to just cut holes with a forstner bit, which makes a flat bottomed hole.  But a quick test revealed that the hole bottom wasn’t as smooth and flat as I would like, and it’s not easy to sand the bottom of a hole.  Maybe I could cut a circular insert and glue it into the hole?  A hole saw would produce an undersized cutout, with the center drilled out by the pilot bit, but Lee Valley sells a tenon cutter that can do the job.  However, it seemed like the tenon cutter might produce a rough edge, depending on the wood used for the insert.

The cabinet top is all angles, with the pointed “backsplash” and the front corners cut off, and the front edge beveled.

As I was testing different sized holes I realized that this project is angled and pointy, not round. Circular holes aren’t right. Hexagonal holes would fit the overall design better. Hexagonal holes also saved me from buying an expensive tenon cutter and resolved the question about whether to use an insert or backer for the holes: if I tried to hand fit hexagons I’d surely end up with unsightly gaps. To cut the hexagonal holes I drilled them out with a forstner bit and then cut the sides hexagonal with chisels. I couldn’t seem to avoid the grain tearing out at the corners of the hexagons, so I had a lot of cleanup to do with rasps and then sandpaper to produce smooth hexagonal holes.

The end grain ripped out along the corner of the hexagon when I chopped the hexagon.

I used fine rasps to get close and then had to turn to sand paper to get the final smooth finish. This work required good illumination, and my loc-line mounted flashlight setup was perfect for the job.

Ceiling mounted flashlight, positioned using loc-line to illuminate the hexagon for rasping and sanding.

I wasn’t sure what wood I would use to fill the holes until I realized that an offcut from the door panels would be perfect. I had a single spalted maple offcut that was just big enough, half the height of the door panel, and a scant two inches wide. Instead of filling the holes from the front, I cut a recess on the back of the door and filled it with the spalted maple insert.

Spalted maple insert applied into the back of the door, with quite a lot of excess thickness.

The back is hidden in use, so the job does not require precision. I therefore cut the recess freehand with the powered router. I prefinished the spalted maple with shellac and carefully glued the pieces in place with cyanoacrylate adhesive, avoiding any squeeze out that would be visible in front, and finally filled the gap around the edges with epoxy.

Spalted maple insert after planing flush to the back of the door.

After planing the inserts flush and finishing they are smooth and cannot be felt by someone who reaches around the back of the door. With careful planning I was able to get four inserts that each featured some of the black spalt lines. This procedure produced crisp, sharp corners at the inside of the handle. The four inserts came out like this:

The sliding doors in the cabinet, with the new hexagonal handles.

Back to Drawers Pulls

Returning to the question of drawer pulls, and drawer fronts I considered various options for different woods for the fronts of the two small center drawers, but nothing I had on hand seemed right. I wanted a single piece I could split in half that would fill the central cavity. So I ordered a piece of slightly spalted maple.

The marked section in the middle will become two drawers for the central cavity visible in the cabinet picture above.

For drawer pulls I started thinking about an applied pull. What shape should it have? On my game table I used a tapered pull, which works well, but really requires a full two finger pinch grip. On my existing dresser I can open the drawers with just fingers underneath. So I tested a rabbeted design, which works well. And to define the final shape I decided to echo the angles of the cabinet top.

Handle shown from the front. The front face and right face are beveled.

End view of the handle shows the front face bevel more clearly.

A question came up about the beveling of the edges of the handle. The cabinet top has its front and the clipped corner edges beveled. In the handle test the front face of the handle is beveled to match, but only the right side of the handle is also beveled. Which looks is better? I’m planning to cut the pulls from the spalted parts at the sides of the board shown above. Hopefully that will bring the piece together, with some spalted components on all the drawers.

For drawer sides I hunted through my woodpile and the best option seemed to be some cherry I originally bought for the file cabinet almost twenty years ago. It was twisted and had a grain pattern I didn’t like, so I didn’t use it for the file cabinet. I went to the local lumber yard but he didn’t have anything cheap that seemed better than the cherry I had already on hand. I wonder how often people use cherry for drawer sides. After cutting the boards to length and then planing out the twist the finished thickness for the drawer sides was less than half an inch. That was some severe twist! The boards have been sitting for over a month now and seem to be stable. The backs of the drawers will be soft maple, also leftovers from the file cabinet. So three different species in each drawer.

Wood waiting to be transformed into drawers.

Bedroom Chest: A Concave Roundover

The roundover is a common treatment for edges. This project has a backsplash which creates a concave corner. A corner like that tends to be hard to finish nicely, and it accumulates dirt and is difficult to clean. It seems like rounding this corner would be a great improvement.

I suppose the normal way to do this would be to apply some molding. I don’t have any molding, but I recently received a pair of molding planes in the tiny 1/4″ size, so I put them to work to create the roundover.

The process using my molding plane is to glue down a strip, cut a rabbet to guide the molding plane, then glue the backsplash on, and finally, cut the roundover.

Above you can see the strip glued in place. Before gluing it down I marked out a 1/8″ rabbet, making sure the top knife line was very well established and going over the bottom line in ink. The top line is important because it will guide the plane to cut the rabbet. I was amazed when I learned how well this technique works without a fence. I started with the edge of the plane resting in the knife line and began to cut. Once I had a groove established, I could level out the plane and work the rabbet down to the highly visible inked line.

The rabbet provides support and guidance for the convex blade of the molding plane. It doesn’t need to look pretty.

Once the rabbet was done, I glued on the backspash. I had a little trouble here because I had cut the front edge of this board at an angle, which meant the clamps were likely to dig into the angled corner edge. I extracted the offcuts from the trash and tried to tape them down with carpet tape to protect the edge, but they shifted sideways and I still ended up with some edge damage. I think the shear forces are simply too large for tape to hold. The final step is cutting with the molding plane.

The HNT Gordon molding plane, with its blade bedded at 60 degrees cut amazingly well in both directions on the wood. Because the molding plane only covers 1/6 of a circle, I had to hold it at different angles to cut a complete quarter round. This process worked quite well, though I got into some trouble with the cut angle shown in the second picture. I had raking light on the flat part but no raking light from above lighting the backsplash, so I didn’t realize that I was overcutting a circular hollow above my roundover. I needed to do a lot of sanding to blend the roundover with the backsplash. And here’s the final result.

Is there any other method that could achieve the same result? I can only think of hand carving with a gouge or maybe a similar approach using a profiled scraper instead of a molding plane.

Bedroom Chest: Case Joinery

Time has been short over the past few years, so progress has been slow, but the case is finally glued together.  It is four feet wide and about 3 feet tall and is dovetailed.  Unlike my file cabinet, the dovetails are half-blind, and will be invisible once I attach the top.  The first challenge was to select the lumber and glue the panels together.   I started with lumber that came in seven foot lengths (from the lumberyard) or 3.5 foot lengths (from the independent sawyer), so I wasn’t sure I had enough material.  The discovery that some of the seven foot material was defective created additional uncertainty.

I decided to glue together panels butcher-block style using my shorter offcuts, and use the resulting boards in the less visible interior parts of the cabinet.  However, I soon realized that this would not suffice: I would still run out of wood.  So I hit the lumber yard and got some plain sawn hard maple to use for the interior panels.

Notice the front panel has two plain sawn boards in the center, flanked by quarter sawn boards at either edge. This will be the bottom of the cabinet, and will always be covered by stuff, so it won’t be seen.

The first joint to cut was eighteen inch wide half-blind dovetails at the bottom of the case.  I laid out the tails using dividers and a bevel gauge, and cut them.  I proceeded next with the pins, which presented several difficulties.  The first one was marking them.  I had great difficulty finding a way to align the boards in my shop for marking due to the four foot length of the tail board.   If my bench were not against a wall this would be simple, but instead I had to balance the boards on edge and clamp them together to do the marking.  At one point during this process the tail board fell off the bench.  You can see the dent at the top right (front board) in the picture.

I sawed the pins and then attempted to hammer the kerfs deeper using a small scraper I used previously for this job.  Evidently the wood species makes a difference for this technique.  This was easy with mahogany, which is soft.  But with hard maple, and the larger scale of the joint, the scraper folded over from hammer blows and became wedged into the kerf so tightly that I need pliers to extract it.   I like this technique, so I bought a specialized tool for extending kerfs.  This tool, with its solid brass back and large handle solved both of the problems.

But my problems weren’t over yet.  Chiseling out the waste can be done in various different ways, but it seems that they ultimately involve taking some thin shavings parallel to the socket wall.  Charlesworth’s clever technique with a slightly thick guide block guarantees a slight undercut so the joint will fit.  At least, that’s the theory.  And it worked great on board number one.  But on the second board the grain direction went the wrong way, and no matter how I tried to execute this technique, the wood would rip up.  I finally gave up and deployed the router plane to try to fix the problem.  (One thing I didn’t try: sharpening my chisels.  I wonder if that would have made a difference.)

After finishing the joint I cut a rabbet along the rear edge to hold a plywood back.  I didn’t do it earlier because I didn’t have the plywood for the back and wasn’t sure about the thickness.  This was unfortunate because it turns out the dovetail should have been cut to accommodate  the through rabbet.

Again, grain direction presented a challenge.  I cut the rabbet on the first board with my rabbet plane and got a nice crisp rabbet.  On the second board the grain went the wrong way for my plane and it reversed.  The result was nasty tear-out.  I tried going in the other direction using various other planes.  I’m not sure if the problem was hard to fix at this point because the existing surface was already so rough, or if it was just impossible to cut the wood cleanly in either direction.   I thought about buying the left handed rabbet plane, but instead I gave up and cut the joint with the router on the router table.  And I found that climb cutting was essential to get a smooth finish from the router.

For the horizontal divider I cut a 1/2″ dado using my HNT Gordon dado plane.  This plane worked very well against my clamped fence.   (Maybe I need their moving fillister plane for cutting rabbets, with it’s 60 degree cutting angle.)

Cutting a 1/2″ dado using a dado plane. The board that will go in this dado is 3/4″ thick.

I only have the 1/2″ dado plane, but none of my boards are 1/2″ thick.  The horizontal divider boards that goes in this dado is is 3/4″ thick.  Two solutions are apparent: widen the dado or trim the board.  In this case, I trimmed the board by cutting a 1/4″ rabbet at each end.   The case also includes a pair of vertical dividers, which are only 5/8″ thick.   In this case, I took the other approach, opting to widen the dado.  This proves to be possible with care by shifting the fence over and cutting again.  (I fails if the extra cut is less than 1/8″—the plane falls off the edge and cuts a slope in this case.)  In all my trials and in 5 out of 6 dados on the cabinet the nicker did its job and the plane produced a smooth exit, but I did encounter one case of spelching, where a large chip pulled off.  I wonder what caused that.

To conserve wood I made the top of the case from three rails instead of a solid panel.   This time I did the dovetail joint correctly to fill in the through rabbet at the ends.   I decided to get a saddle square dovetail marker, and I must say it really did streamline the tail marking.   It is nice to  quickly mark the square line across the edge and the sloping line down the face of the board without having to fuss with lining up the marks.

A dovetail saddle marker like this is helpful because you can mark across the top and then down the front in one step.

The resulting rail ends:

The assembled joint looks like this, with the extra block to fill in the gap in the side panel:

These joints certainly won’t win any prizes. They may be the worst fit dovetails on the internet. I think the first dovetails I ever cut looked quite a bit better.  But these joints, as bad as they look, didn’t rattle around once assembled, and the big gaps will be hidden when the top goes on.  Luckily the chunk that broke out on the right side didn’t break through the surface of the board.  The only part that will be visible is at the back of the case, and that part is tight:

The final step before the glue-up was to cut grooves for the sliding doors. I’ve had a lot of trouble cutting grooves (and rabbets along the grain) on this project, so I wasn’t sure of the best approach. My first attempt was to mark the edges of the groove, and chisel out along the groove. This left a block of waste in the groove, which I attempted to remove using the Veritas combination plane, which I selected because it could be configured for left-handed use as required by the grain (except for the section where the grain is reversed). The plow plane has a circular nicker blade but this plane has short straight nicker blades that are apparently meant to bend outward for adjustment with small set screws. Unfortunately, I didn’t realize that the nickers needed to be removed for this job. Because I was removing a strip of wood with a space on either side, the nickers weren’t engaged in the wood and they splayed out and started cutting along the keeper material adjacent to the groove. I didn’t notice the problem until the board was badly scarred with many cuts along the side of the groove. I attempted to repair the damage by inserting patch pieces, thinking that the second groove would hide the joint, but I miscalculated the location of the second groove. I may redo the really obvious patch shown here.

Ugly patch, right in the center.

I made a second patch that is several inches long which blends somewhat better. Can you find it?

Less obvious long patch.

I tried cutting the groove undersized using the combination plane and then using a chisel to clean up the side walls afterward, but the walls tended to crumble and it was hard to make them smooth. I did the last groove using the combination plane with its nickers set to the full width of the groove and that worked the best.

Finally the it was time for glue. The resulting glued up cabinet still lacks the back and the top, which I think will make it easier to fit the drawers.

Here it is with the top and backsplash boards resting on the case.

The next step is to decide on the final shape for the top and glue the backsplash and to together. After that, I will make the drawers, and I have to resolve the last major design question: what will the drawer pulls look like?

Charging Station

After a few years of testing and a few changes to the original design, the time came for the final version:  we got more devices and the prototype wasn’t big enough.

I made the final version from canarywood scraps I had lying around.  The space on the wall allowed me to fit a thirty inch wide shelf to hold the devices.  Hopefully this will suffice for all the devices the household requires.  To make the shelf I glued together two pieces of canarywood, drilled holes at the base of each slot, and finally cut out the thirteen slots with a hand saw.   Shaping and smoothing these slots and, finally, sanding them was extremely time consuming.   My saw cuts weren’t precisely tangent to the holes I drilled, so those transitions all needed attention.  I had to round over all of the top corners.  Finishing end grain is always more work, and this design creates a lot of exposed end grain that is hard to get to.   Is there a way to change the design to make the build easier?

I glued a continuous strip of the EPDM rubber along the slots. I punched a 7/64″ hole and then cut a slit leading up to the hole.

My final selection for the cable gripping rubber was EPDM rubber, 1/16 inch thick, and 40A hardness.   I originally used 1/8 inch holes.  The 1/8″ holes are great when they work, because they grip the cables tightly, but they are too small for some thick USB cables.   I had to increase the size to 7/64″ to accommodate these fatter cables.  This does mean that the rubber almost never actually grips the cable.  It just confines it.  For my prototype I glued on the rubber using epoxy, but the rubber peeled off in some places.  In looking for an alternative I found Nexabond, a slow curing cyanoacrylate adhesive, which seems to dissolve the rubber and create a very strong bond.  Nexabond is now sold as Rapid Fuse.  I used the variety marketed for wood.   I found that it’s not possible to clean it off the rubber, so I had to be careful when applying it to avoid excessive squeeze out, but to use enough to secure the rubber all the way to the edge of the wood.

The rubber loosely grips the cables. The USB plug can rest in the space in front of the rubber in each slot.

The cable management box was hard for me to design.   My original design left the wrapped cables exposed.  I found that users often leave the ends of the cables dangling over the cable management box rather than securing them above on the shelf.  The dangling cables combined with the exposed wrapped cables form a very busy visual image, and it is hard to identify the loose ends that you may want to plug into your dying device.  In the prototype, I added a cover secured with a pair of magnets.  Maybe this approach could work somehow, but two problems would need to be addressed.  I was never sure where to put the cover after removing it, and I found it hard to close it because the cover would snap suddenly into place and I had to make sure it didn’t capture any cables over its whole width.   However, a normal hinged door would extend 15 inches, which seems unwieldy.  I  considered doors that swiveled down, but one of them would collide with the USB hub.  Finally, after talking with a friend about my design challenge, I revisited the idea of a hinged door and hit on the idea of a door that folds in half.

Two doors, each with a hinge in the center so they can fold in half.  Note the continuous grain lines across all four parts of the door.

The center section opens first.

 

If necessary you can open the second section of the doors, which have their own separate magnetic latches.

Selecting hinges was another challenge.   I hadn’t been planning to spend so much on hardware for this project.  The hidden hinges in the middle of each door are Soss Invisible hinges, and I ended up using Brusso brass butt hinges to mount the doors to the frame.   The Soss hinges come in a brass finish, which would have blended better, but when I found these on ebay for half price I decided I’d take them.  I love magnets, but getting the right magnetic force seems to be an ongoing challenge.  In this case, I mounted 3/8 inch magnets using screw in cups.  The resulting magnetic force was excessive.   One solution is to recess the mating washers farther into the wood (to increase the distance), but once the magnets are installed it is impossible to remove them.  In fact, once the steel cups are installed I find that they fit so tightly it is impossible to remove them, even before screwing them in.  Covering the magnets with high friction disks provided some extra separation that weakened the magnetic force enough to make the doors useful, though they do still stick shut a little bit more strongly than I would prefer.

For securing the cables I use a pair of 3/8 inch dowels and wrap the cables in a figure eight fashion.  I have seen quite a few gizmos for managing cables and, from what I can tell, none of them works as well as just wrapping cables in a figure eight; the cables don’t tangle, and you don’t need a special device.  Try it with your earbuds.  A strip of velcro holds each cable in place.  I used a two inch wide strip of white velcro hook material for the back of the box and I secured the cables using 3/4 inch black loop strips.   Reportedly the loop side of the velcro wears out first, so I used it in the more easily replaceable location.   Along the top edge of the box I made small cutouts for rubber cable holders.  These hold the cables up if you open the box.

The doors open all the way out and can tuck up against the wall at the sides. We secure the cables using figure eight wrapping onto two posts, with a strip of velcro to hold them in place. I chose white velcro for the background so it’s easy to see the black velcro that holds down the cables.

Installation of the Soss hinges requires a weird shaped mortise 3/8 inches wide with rounded ends and a deeper center section.  I drilled this using a centering drill guide and a brad point bit.  I had some trouble with hole depth and later found myself trying to deepen parts of the mortises with chisels.  But eventually I got the mortises cut.  For hardware installation I chose to use machine screws, both for the Soss hinges and the Brusso hinges.  Many people recommend machine screws for wood, especially when the screws are small and short.  I thought I would be installing and removing the screws many times, so this supported my decision to use machine screws.  In the case of the Soss hinges, the fit in the mortises was very tight.  They weren’t going  anywhere.  It was hard to take the hinges out after test fitting them in the holes.  Strength of the screws wouldn’t have made a difference.  And since it was so hard to install and remove the hinges I ended up doing it only one time and doing the finishing with the hinges installed.   I also broke two 4-40 taps cutting the threads.  In retrospect, I think this happened because I pre-drilled holes that were a size too small.

I installed the Brusso hinges using chisels and a router plane, a process that I enjoyed much more than drilling with a guide.  And I didn’t break the tap when cutting threads for 2-56 screws.  Using machine screws here seemed like the right thing to do.  The hinges didn’t stay in their mortises from friction alone like the Soss ones, and the use of machine screws enabled me to use longer screws on the frame and shorter ones on the door without having to buy two boxes of screws.  My wire cutters cut easily through the brass machine screws so I could make the lengths I needed.   I did end up installing and removing the hinges several times.

One disappointment is that the Soss hinges have a little bit of slop in them.  I’m not sure if I loosened them up somehow while prying them out of their mortises after test fitting, but if I close the doors without trying to force them upward they don’t create an even gap.

Uniform gap between the doors.

Uneven gap between the doors, narrower at the top.

 

The final component of the charging station is the hub holder.   As long as we charge devices using cables, the rest of the ensemble can remain unchanged, but this hub is the part most likely to change in the future.  It already changed: I have a new hub with more ports.  I didn’t want to work too hard on this part so I used a simple design that is very easy to make and somewhat adaptable—unlike the prototype it can at least accommodate charging hubs of varying length.  This design requires no complex joinery since the wood grain all runs in the same direction.  I tried to shape it to echo the curves of the shelf at the top, with the the back section sticking out to the sides for easy screw mounting.

Very simple hub holder design with open ends.

I think overall this is a great design for a charging station. It only uses wall space, not desk space, and keeps all our devices out of the way. I’m happy with the final result. The only thing that could be improved is the location of cable holding holes in the rubber. These holes are about an inch behind the front of the slot, and this is a little bit too far. Three fourths of an inch would be better.

Bedroom Chest: First Steps

My latest big project is a chest to go at the end of the bed. We had a bench there, but piles of clothing and linens covered its surface, and hence I could never actually sit on it. Storage in a small, old house is scarce, so I decided to replace the bench with a storage cabinet. The standard chest at the end of a bed opens on the top. If we had such a chest we’d never be able to open it, so my design features sliding doors and drawers. The top remains available for piles of clothing, and a backsplash prevents the piles from dripping off onto the bed.  The current design appears above, though I still have some uncertainty about the drawer widths. Work has been proceeding at a glacial pace over the past couple years.

This cabinet will be made out of quarter sawn hard maple. I had difficulty buying quarter sawn maple. I found a guy with a chainsaw who sold me a small lot cut from one log. It had some very nice boards in it, some up to 11 inches wide, but the boards were only 46 inches long, which won’t work for a four foot wide cabinet.   Nobody has 11 inch wide material; most online vendors said their boards were four inches wide, which wasn’t appealing. I finally ordered some wood that was over 5 inches wide with some nine inch boards.  The length ended up being seven feet, the worst possible length for my four foot wide cabinet.   As I began to work the wood I found that the guy with the chainsaw delivered nice looking, wide boards, but they were pretty badly twisted, so jointing the lumber by hand was a lot of work. But the real lumber yard delivered wood that was riddled with cracks across the face of the boards. I’m guessing this is the drying defect known as “honeycombing.”

This board has several cracks across its surface that you can see if you enlarge the image.

For the panels of the sliding doors I selected some spalted quilted maple material. This too, turned out to suffer from drying defects. I had the option of returning it or working with it and ended up deciding to fill the cracks and move ahead, rather than trying to locate a different panel. I tried to plane the material slightly to decrease the size of the cracks…but they got bigger instead. I chose to fill the cracks with black epoxy, hoping that it would match the spalting lines and blend in. It seems like most people think this looks fine, but I’m less enthusiastic.

As always, the process of selecting wood for different parts of the project went slowly. I began by choosing wood for the sides because I wanted to use the short, wide pieces there. Then came the task of selecting rail and stile material. One thing I love about quarter sawn wood is the ray flecking, but for the rails and stiles I wanted it to be really more rift sawn: straight grained without fleck to provide a good frame to the busy internal panel. Then it was time to get to work. I cut the grooves using my Veritas plow plane.

Note the fuzzy tear out towards the back end of the plane on the front edge of the groove.

I had a lot of problems with tear out while making these cuts. Part of the problem was user error: if I tipped the plane even a bit it could rip out a chunk on the side wall of the groove. But because the wood is quarter sawn, the edge, where I’m cutting the groove, has badly behaved grain. I did find that the front edge of the groove came out worse than the back one every time. I think this is because I can tip the plane toward me but the fence prevents me from tipping it the other way. I switched my reference around and referenced from the back of the panels to get the best looking show side. But it seems that ultimately to get a nice groove in material with reversing grain you have to precut the groove edges with a chisel.

The spalted maple panels were very porous, and when I started applying shellac the liquid quickly vanished into the wood. When the finishing was complete I discovered that the wood had warped considerably. I tried to flatten it by putting some shellac on the back. This helped a bit, but the panel remained warped. People use to say you needed to finish both sides of a panel to prevent warping. Then this idea got attacked as a myth. I wonder if I had finished both sides exactly the same would the panel have stayed flat and made the assembly easier—it’s more difficult to squeeze a warped panel into a groove.

This panel was flat before I applied shellac. Note the shadow of the straight edge on the wood.

I cut mortise and tenon joints to hold the panels together. The joints weren’t my best fitting. I had been wondering whether to drawbore or not, and decided I had better drawbore.  A drawbore is a joint where a peg is inserted through the joint but holes are misaligned so that the peg has to bend a little bit and it strongly forces the joint together.  Based on Schwarz’s recommendation I offset my 1/4” drawbore holes by 3/32” for my first door. I made riven white oak pegs using a dowel plate and cut a taper at the starting end. When I went to hammer the pegs home, though, I had some problems. I had tested the joint with drawbore pins and it seemed to be OK. But the pegs splintered inside the work, with only part of the peg emerging on the back side. Additionally, they forced the joint to come together crookedly so that the door didn’t lie flat on the bench. When I remembered to put glue on the peg it worked a bit better, but I only remembered one out of four times to do that. Application of a mallet and clamping the door flat onto the bench seemed to correct the problem.  The pictures below show four pegs from the back.  The top left is a peg that was lubed with glue and went through neatly.  The bottom left peg opened a gap, the top right peg was somewhat mangled and the bottom right beg lost a quarter of itself somewhere in the hole, leaving a gaping space.

For the second door I adjusted the procedure. I used a 1/16” offset and I put the pegs into a cup of glue so I wouldn’t forget to lubricate them with the hide glue I was using. This door went together much more smoothly, without the problems I had on door number one.  Some of the pegs look bad on the back of the door, but as these are sliding doors, nobody will see them.  The front pegs look good.

The last issue is securing the panels so that they stay centered in the groove if the panel shrinks or expands.  I’ve seen special foam balls sold for this job, but that solution wasn’t appealing.  It sounds like a standard solution is to hammer in a nail at the panel center but I realized I wasn’t sure how the nail should go in.  If I tried to angle it then the nail would almost completely miss the panel.  I had some 1.25″ cut nails handy.  I trimmed them to be about 1/2″ long, oriented them correctly to the grain of the frame and tapped them into pilot holes.  Nothing split, and hopefully they actually pierced the panels, so they should do the job.  I wonder if a dab of glue would have been an easier solution?  Would that hold well enough if I can only squirt it into an already assembled panel from the outside?

Finished door panels. Note that the rails are overly long and still need to be cut flush with the stiles.

Now it’s back to lumber selection. I need to select boards to use for the top of the cabinet, and then see if I have enough wood to make the dividers. I am thinking that I may have to glue up three foot lengths into a four foot long panel butcher block style to use the lumber I have on hand.

I haven’t quite figured out the proportions for the drawers.  Here is a subtle change in the drawer proportions.  Which is better?

Drawers at 2:1 ratio. Center drawer 9″ wide.

Drawers at 5:3 ratio. Center drawer 10.5″ wide.

Another outstanding design question is: can I do something with the drawers to unify them with the much darker spalted panels on the sliding doors below. Perhaps spalted maple drawer pulls would have this effect?

Magnetic Wood and Magnet Selection

We find hanging utensils in the kitchen to be the best storage method; most of the vertical space in the kitchen is covered with kitchen equipment.  However, the sides of the cabinets above the sink had nothing hanging on them! This problem demanded a solution. Last time I did a project like this I made pegboard, but pegboard is inflexible both in spacing and in the type of hooks available. This time: magnets.

I started with 1/16″ thick sheets of steel, which I covered with oak veneer. Technical support at 3M advised me to use spray adhesive, so I adhered the veneer with Super 77. The trim on the cabinets conceals the side edges, but not the bottom edges, so I epoxied small oak strips along the top and bottom to hide those edges and blend into the cabinetry.

Once I had the veneered steel screwed to the cabinets I realized that I couldn’t find magnetic hooks suitable for hanging kitchen tools.  I could hang a few things with Super Fridge Magnets and some things with the Standoff Magnetic Tool Holder, but most of the things I wanted to hang would require a different solution.

These  magnetic bases have a protruding threaded rod. To transform them into hanging rods I attached standoffs, metal tubes that are threaded on the inside. At McMaster I could buy standoffs in a variety of lengths, though for some reason the stainless steel ones were twice the price of aluminum.  To get a finished look I found two options. McMaster sells elegant end caps for the stand offs, but they are expensive—more than the shorter length standoffs. You can see them below in stainless steel (which is the same price as aluminum). I also bought a box of stainless fillister head machine screws which make reasonable looking caps for the standoffs at just pennies a piece. This scheme enabled me to make hooks as long or as short as needed. I worried that the absence of a hooked end might allow tools to fall off the wall and plunge into the sink, but that hasn’t been a problem for most things.

Magnetic base with threaded rod.

Hooks with fancy end caps.

Magnetic base with aluminum threaded rod and stainless steel fillister screw.

The one exception is the red funnel which slips right off of a rod. A simple solution is to insert a screw that is longer than the threaded rod so the screw head acts as a stop.

Hanging this funnel required a trick to keep it from sliding off the rod.

We also have some spatulas whose hang holes do not admit a 1/4″ shaft, and the threaded rod does not come in a smaller size that is compatible with the magnetic screw bases. I attached a 1/2″ diameter magnet to a small piece of wood and inserted a 3/16″ diameter stainless rod to create a suitably sized hanger. It didn’t work: I planned to hang four spatulas from this rod, but the hook would slide down and fall off the wall if I loaded it with more than two of the utensils.

Next I tried polymagnets. I recently learned about these magnets where the magnetic field varies spatially across the magnet to produce different effects. They make several types of magnet pairs, including the spring, latch, and centering magnets. For this task I was testing the “attach” type magnets, which supposedly concentrate the magnetic field closer to the magnet so that the magnet grips more strongly. I had on hand some 1″ diameter, 1/32″ thick “attach” magnets as well as two 1″ diameter, 1/8″ thick “attach” magnets (one with a mounting hole and one without). The 1/32″ thick magnets have the same volume of magnetic material as the 1/2″ diameter, 1/8″ thick magnets I used to make my unsuccessful hooks. Another observation is that two of the 1/32″ magnets got stuck to each other at one point and they were extremely difficult to separate. It was impossible to slide them apart like one usually does to separate rare earth magnets. I had to separate them using a wedge, something I’ve never had to do before, even with larger 3/4″ diameter, 1/8″ thick magnets. These magnets are not weak.

I glued a 1″ diameter 1/32″ thick “attach” magnet to a small piece of wood and again inserted a length of steel rod.   This new hook was very weak and slide right down the wall.  I glued on a second “attach” magnet, and now it could hold the weight of 3 spatulas, but not 4.  When attached to the refrigerator, however, the hook would hold the necessary weight—the four spatulas I wanted to hang weighed about a pound in total. Note also that the rolling pin weighed more than a pound and yet was easily held to the veneered steel by one hook with a 1/2″ magnet.  The hook with two polymagnets has double the amount of magnetic material,  but it fails to do the job.

I abandoned that design.  The hanging rod in my original design was below the magnet instead of centered over it.  The wood was 1/4″ thick.  The magnets are 1/8″ thick.  I didn’t think the remaining 1/8″ of wood sufficed to support the hanging rod.  The off-center hanging rod seems to make the shear hold weaker because the load on the rod can tilt the magnet away from the surface.  I made the centered rod design (right) by using a magnet with a screw mounting hole in the center. The rod goes through the screw mounting hole, and I filled the space with epoxy to ensure that the rod would be well supported.  This new hook holds all four spatulas without any difficulty.

Spatula hooks. The bloodwood hook on the left with a conventional half inch magnet has the hang bar off center and can hold only two spatulas. The chechen wood hook on the right, with a one inch polymagnet and centered bar easily holds four spatulas.

 

Measuring magnets

So what was going on with my magnets? I tried to measure the capacity by filling a bag with weights (dried beans) and determining the point at which the hook began to slip. This was kind of messy and I didn’t feel very confident about my accuracy, but I did find that the hook with the two polymagnets held 4.25 lbs on the refrigerator and only 1.1 pounds on the wood covered steel. One important factor in this sort of holding power is friction. Is it possible that my finish on the wood was too slippery? Or did the magnets simply hold with less strength on the wood.

To get to the bottom of this I purchased a Chatillon force gauge cheaply on eBay. This device measures force in pounds and enabled me to measure the pull force to detach magnets from surfaces as well as the shear force (the hanging load that would cause the magnet to begin sliding). Measuring shear force is relatively easy: I attached a loop of string to the hook and pull downward with the gauge.

Measuring pull force is a bit more difficult. I used a strip of Tyvek and placed the magnet over it. This means that the magnetic force is decreased by the extra distance created by the layer of Tyvek. It also is difficult to be sure that the pull is applied directly perpendicular to the plane of the magnet, and I suspect that an angled pull may lift the magnet more easily.

Measurement of the magnets resulted in a complicated set of data with some inconsistencies. I tested magnets on two surfaces, the refrigerator and the wood veneered steel. If the pull force of the magnet is F then the shear force is supposed to be equal to σF where the coefficient of friction, σ, depends just on the surfaces. Lee Valley sells two self-adhesive high friction materials. One is their High Friction Disks, specifically marketed for use with rare earth magnets. The other is the Super High Friction Tape. When I ordered the polymagnets I also included some Traction Tape to use with them. My hook that wouldn’t support a pound of spatulas gave the following test results

Two thin Polymagnets glued to wood

	Pull Force (lb)		Shear Force (lb)		σ
	Fridge	Wood	Fridge	Wood	Fridge	Wood
Bare magnets	5	1	1.5	0.25	0.3	0.25
Friction disks	3	0.5	3.75	1	1.25	2
Friction tape	1.75	0.5	5.5	2	3.1	2
Traction tape			4.25	1.1

When placed on the refrigerator the pair of 1/32″ thick 1″ diameter “attach” polymagnets gave a respectable pull force, five pounds with nothing but a sheet of Tyvek separating them from the refrigerator. The friction disks are only 0.022″ thick and the friction tape is 0.016″ thick. But this small extra separation from the metal created by the friction disk or friction tape reduced the pull force considerably to 1/3–1/2 of the original amount. Despite this decrease in pull force, the shear force increased. Without a friction tape of some kind the coefficient of friction was around 0.25, but with friction tape it rose as high as 3.1. Note that for this hook the high friction tape gave the best result: with two pounds of holding power even on the wood it would have sufficed to hold the 1 pound load of spatulas.

Why is the magnetic force of attraction to the refrigerator so different from the force of attraction to the veneered steel?  And why can’t two magnets hold on as strongly as a single magnet hook? Is the high friction tape really so much better than the other tapes?  I made the same measurements of the screw bases:

Small (16mm) screw base magnet

	Pull Force (lb)		Shear Force (lb)		σ
	Fridge	Wood	Fridge	Wood	Fridge	Wood
Bare magnet	4.5	3.5	2.75	1	0.61	0.28
Friction disk	2.5	2.75	2	2	0.8	0.73
Friction tape	2.5	1.5	2	2.5	0.8	1.7

The strength of attraction to the wood and the fridge are closer together in this case, and the shear forces are very similar. In some cases the attraction to the wood is higher than the attraction to the fridge. This result is quite different from the previous one. One anomaly stands out: the shear force for the bare magnet on the fridge is very high. I noticed that when I dragged this magnet on the fridge it was scraping little white bits of the vinyl off, so I think that rough edges of the magnet were digging in and providing a huge boost to friction. I tried sanding the base but it didn’t significantly change the results, though. (Maybe I didn’t go far enough.)  Another anomaly is the high σ value with friction tape on wood; I have no explanation for this one.  These screw bases feature a 1/2″ diameter magnet that I assumed was 1/8″ thick, which would mean they have half the magnetic material of the two polymagnets I used above, and yet the holding power on the wood is higher. Moving on to the larger screw base:

Large (20mm) screw base magnet

	Pull Force (lb)		Shear Force (lb)		σ
	Fridge	Wood	Fridge	Wood	Fridge	Wood
Bare magnet	4.75	6.25	1.5	1.25	0.3	0.2
Friction disk	3	4	3.25	4	1.1	1
Friction tape	3	4	3.5	4.5	1.2	1.1

This larger base clings to the fridge with greater strength than the smaller base, and on the wood it is even more powerful. The shear force strength is also somewhat stronger on the wood. So a bigger magnet is gripping more tightly and giving more holding power, right?

Wrong. Both screw bases have the same sized magnet.  The larger base has a plastic ring encircling the magnet.

I disassembled one of each hook and found that the magnets were slightly bigger than 1/2″ in diameter (0.54″) and at 0.15″ thick, they were thicker than expected.  And they were indeed the same.  These neodymium magnets come in different grades with different strengths, but I tested the pull force and found no difference: both held to the fridge with 2 lbs and the wood with 2.5 lbs.

So apparently the difference in magnetic forces depends on the way the magnet is enclosed. I measured the pull force for a bare 1/2″ magnet and got 1.5 pounds for both the fridge and the wood. When I put the magnet into a steel cup the force rose to 3 pounds.  The observations above suggest that I might get even more force if I had an oversized cup surrounding my 1/2″ magnet.  So I tried inserting my 1/2″ magnet into a base designed for a 5/8″ magnet.  The force rose slightly to 3.25 lb on either the wood or the fridge.  I didn’t see the striking increase I got with the magnet base on the wood.   I tried a larger 3/4″ magnet cup and the force decreased slightly.  The only curiosity was that when I inverted the magnet cup, so the magnet was backed with steel but not covered on the sides, I saw an increase in the attraction to the wood to 3.5 lb, while the attraction to the fridge declined to 2.5 lb.

What conclusions can we draw from these measurements? Clearly backing the magnet with steel makes a big difference.  It seems like it’s hard to predict the attractive force of different configurations, so measurement may be the only way to know what will happen. The thin polymagnets did not adhere well to the wood. Perhaps their magnetic force is shorter range than the normal magnets, and the veneer is thicker than the vinyl that covers the refrigerator. This behavior doesn’t offer any obvious advantages, so I don’t plan to use those magnets again.

The coefficient of friction for the bare magnets came out consistently around 0.2–0.3, and inserting friction tape of some kind improves this to about 1. The small gap created by the friction tape significantly reduces magnetic pull, but you still get more shear force. Don’t skip the friction tape if you care about shear loading! But I didn’t get consistent friction coefficients as claimed by the physics books. My measurements were all over the place, ranging from 0.73 up to 3.1. Why the big spread? The friction coefficient is supposed to be independent of contact area, but I’m observing higher values when I have more contact area and the lowest values when contact area is the least. The high friction tape seemed to perform better with the polymagnets, but not at any other time, so I can’t identify a winner among the friction tapes.

Tilting can play a role in limiting the load a magnet can hold on a vertical surface. These magnetic hooks fail  not by sliding down the fridge but by tipping forward: the failure isn’t in shear.  I tested my wooden hooks (pictured above) on the veneered steel surface.  The bloodwood hook could support 1.75 lbs of force at the base of its 1.5″ rod but only 1 lb of force at the tip.  The chechen hook has a four times bigger magnet and could support 5 lbs at its base, but again only 1 lb at the tip of its longer 2.125″ rod.  When the load was at the tip it  usually failed by tilting, or it vibrated as it moved.  Perhaps even when magnets are sliding down the fridge they are tipped forward, compressing the friction tape at the bottom and moving the magnet away from the fridge at the top.

I’ll finish with some measurements of a few other polymagnets. I have a 1″ diameter, 1/8″ thick “attach” magnet. It has a marked side that I thought was supposed to be the active side. Pull force on the fridge was 7 lbs on the active side and 13.5 lbs on the reverse side. On the wood I got 3 lbs on the active side and 5.5 lbs on the reverse side. I also have a polymagnet with ring shaped magnetic regions designed so that a pair of them will center on each other. This magnet is 3/4″ in diameter and 1/8″ thick. With the marked side to the fridge it had a 9 lb pull force and with the reverse side only 4 lbs. On the wood, this magnet gave a pathetic 2 lb pull on the active side. A normal magnet of the same dimensions clung to the fridge with 2 lbs of force, and the wood with 2.5 lbs. The 1/2″ magnets I tested above are only 44% as big and yet 75% as powerful in this situation, so for hanging stuff on the fridge, at least, save money and use the smaller magnets—or spring for that centering polymagnet.

 

Draining Rack

We have various soaps next to the kitchen sink, and I noticed that as a result, the sink area was always wet, which led to mold growth. To address this problem, I tried building a drainage rack out of wood, which I hoped would allow the water to dry and prevent the growth of mold. I’m not sure whether it was helping with the mold, but it turned out to have another problem: the wood itself produced brown stains on the counter.

Wooden tray with soap…and stains visible on the left.

Underneath the tray it looks worse.

It seemed that for this project, I needed a different material.  I envisioned something with holes in the top and a sloping drainage tray to send water back to the sink.  Shapeways offered a 3D printed ceramic material that is dishwasher safe and food safe.  It seemed ideal.   So I started designing in SketchUp.  SketchUp is easy to use for lots of things, but I found it tricky for this task.  Arranging the holes in the top proved tricky, tedious, and hard to change once it was done.  The printed object will be nicer with rounded corners and edges, but SketchUp is not very good with rounding over corners. But eventually I got a model done and submitted it to Shapeways.

It was rejected because the walls of the design were too thin somewhere.  After resolving that problem my design got rejected because it wasn’t adequately supported.  But the exact nature of the support I needed remained elusive as I tried to redesign the model to comply with their vague requirements.  Then the ceramic material got discontinued entirely.

Months later I was admitted to the Shapeways pilot project for a new porcelain material. I had to reduce the size of my model to make it printable, but the only hitch I had was failing to meet a minimum size requirement.  So finally, I was able to make the print.

My original design was a two piece ceramic structure with a drainage tray in the base and a top that lift off for cleaning.  This was quite expensive, so in a quest to lower the price, I devised a design with a single ceramic part and a slit to hold a drainage tray.  I ordered a piece of white plastic from McMaster and cut it to size to fit into the slot.

The result is functional and reasonable looking.  I was a little disappointed by the way the glaze looked:  I was expecting a more uniform deep green color.  The long unsupported top span sagged a little bit during fabrication, but this doesn’t affect its function.  The rack has stood up to a couple months of use and has definitely improved the sink area.

Here you can see the plastic drainage tray. The tray does sag a bit in the center.