How the time flies – it is two years since I wrote a series of blog posts „Showing off my wood“ where I have shown various woods at my disposal for crafting. I have so much material in fact that it is not improbable but downright impossible for me to use it all up making knife handles and knife blocks, I just cannot make that many different knives alone. So I would like to make some high-quality end-grain cutting boards to convert at least some of that massive amount of material into something useful.
I started last year but I hit a snag. I need to mate wooden surfaces together perfectly, but there is no convenient way for me to flatten wooden surfaces in reasonable time and in scale. My manual method is precise, but also tiring and time-consuming. I need a drum sander to make even a few end-grain cutting boards. And I cannot buy one for two reasons. Firstly I don’t have the money. Second, I don’t have the space needed for one.
But since I have managed to build myself a belt sander, I decided this year to spend some time trying to build a drum sander too. I had more than a year to think about it and with the money these things cost, even if I spend a whole month building one, it would still be worth it.
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I started by gluing three large pieces of black locust wood together to form a large prism through whose center I put a 10 mm threaded rod. I cut the edges off on a circular saw and then I stood in front of a bit of a problem – how to turn a large-ish wooden cylinder without a lathe. I rigged up a temporary wooden structure that allowed me to span the prism in such a way that it could run against the edge of the circular saw whilst being continuously rotated with hand-held akku drill. I hope the picture makes it clear what I mean.
© Charly, all rights reserved. Click for full size.
It made an absolutely unholy mess and I was terrified the whole time but I succeeded in making a rough cylinder round enough to progress to other works. I will make the cylinder perfectly round and concentric with its rotational axis later.
© Charly, all rights reserved. Click for full size.
I swapped the threaded shaft for a smooth 10 mm one and to secure it to the cylinder I drilled 3 mm holes throughout it and the shaft on both ends and I drove 3 mm hard steel through the hole. I hope it’s strong enough for the forces needed, if not and it shears off during work, I will have to think up something better. I also cut grooves in the shafts to secure one ball bearing on each side with circlips. I later decided to use two ball bearings, with the second one being put near the first one and not being secured with circlips. As you can clearly see, I am making things up as I go along and I do not always know what I am doing.
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A 15 mm particle board from an old PC table serves as a base to build upon. To hold the ball bearings I cut short boards from hardwood (beech) and I made cutouts for the ball bearings between two pieces and screwed them together with long wood screws. It appeared to be reasonably strong and it held the ball bearings firmly, but it was a bit wobbly. So I glued 15 mm particle boards to the beech boards to widen the bases a bit.
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While the glue was setting on that, I trimmed the edges of the cylinder. I used the boards that held it in the circular saw jig and a hand-held drill as the source of rotation again. That left me with only one hand free to trim the edges but a hacksaw blade proved to be quite efficient at that. Setting the initial groove was a bit fiddly but once started, it went easily, albeit slowly. The edges are not perfectly square and flat but they do not need to be.
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Once the boards for holding the ball bearings were glued together, I glued them to the base with five-minute epoxy. Epoxy is expensive, but I needed a strong bond to make subsequent works easier.
© Charly, all rights reserved. Click for full size.
Once the epoxy cured, I added 4 80 mm wood screws through the beech cores and then also multiple 6 mm bamboo dowels glued in with PVA glue. I do hope that is strong enough in itself but it was additionally reinforced with the last step.
© Charly, all rights reserved. Click for full size.
There are strong anchor points on the base for the ball bearings and I changed the way they are held between the boards from the temporary wood screws to the final solution – I put two M8 rods through the whole thing with pronged nuts hammered into the particle board base and wing nuts on top. It holds the ball bearings firmly in place and the cylinder can rotate freely.
And this is where I am right now. Next, I can start working on the propulsion part.
During all this work I am also spending a lot of time just thinking not only about each step but also about what might be the main challenge of this project – the adjustable sanding thickness. I have several ideas but they all are fiddly and complicated and I would like to keep things as simple as possible. The simpler the mechanism, the fewer potential points of failure. I won’t even attempt to make some sort of automatic feeding – the wood will be fed through the machine manually (if I manage to make it work).
I always tell apprentices that the table saw is the most dangerous tool in the shop. Your first picture scared the living daylights out of me. :-)
You could look a the woodworking machinery page by Matthias Wandel. He has built a lot of wooden machines over the years. There is an article about a thickness sander, which has a simple tilting table. The only downside I could think of is that if you feed in a board from the wrong side, that would be an excellent way of launching it across the shop. I guess that’s why thickness planers generally have these moveable teeth inside to prevent kickback.
@rsmith, thank you for the links. I watched several of Matt Wandel’s videos in the past but I did not know about the webpage. I do consider the idea with the table hinged on one side and lifted on the other, I am just wary of doing it with a single screw in the middle, I am concerned about the stability since my table cannot be as thick and sturdy as his. The funny thing is that I plan on using the same idea for truing the drum from the start. Well, there are a limited amount of ways to do that, and it’s not the first time I reinvented the wheel :-).
The table saw is dangerous and I am constantly afraid of it. That’s why I did this very carefully and slowly, taking off no more than 1-2 mm at a time. And whilst it did work, I do not intend to make it a habit. If this is a success, I also plan on building myself a better and bigger lathe than the one I currently have (also DIY, powered by a drill).
Using a single screw in the middle, twisting would be the most obvious problem. If you are using plywood (or if you’re making your own by bonding layers together) this can be mitigated by orienting the layers differently. Instead of having the layers run parallel to the length and width of the table, have them running at 45°. This will increase the table’s resistance against torsion. This will come at the price of a reduces longitudinal stiffness, but that could be addressed by running a couple of stringers along the length direction on the bottom of the table.
I’m prefectly fine with powered metal lathes, since they generally hold the material in a chuck and the tool in a toolpost. But with an electrically powered woodworking lathe both the workholding (often basically just turning between centers) and the fact that you’re often holding the tools by hand makes me wary. So if I had to build one, I’d probably go for a treadle lathe. Being man-powered it would probably stall rather than launching either a chisel or a workpiece in the direction of my face.
The treadle lathe is great for someone planning to do a lot of lathe work, but it is a fair amount of work to make and can’t be folded for storage. On his TV show, The Woodwright’s Shop, Roy Underhill built a lathe that used the spring pole principle but with a short strong wooden spring combined with a lever system acting as a gear to multiply the travel distance of the spring. Also, the trestle frame of the lathe folded flat so the whole machine could be stored in a very small space. Search YouTube for “Spring pole lathe Roy Underhill” for a short video that demonstrates it.
The TV show was put on DVD years ago, I assume a video of the lathe episode is rentable somewhere.
Getting back to the original goal, if I understand correctly you want to flatten small pieces of wood to glue together to make a checkerboard cutting board, correct? Why not simply clamp a large handplane upside down to your workbench? Then you can hold the pieces in your hand and run them over the blade to flatten. Use a heavy leather glove to protect your hand in case you slip.
To make good right angles, use c-clamps to fasten a square piece of wood to the handplane to act as a fence.
@moarscienceplz, you perhaps missed the beginning of my article, to wit: “…but there is no convenient way for me to flatten wooden surfaces in reasonable time and in scale. My manual method is precise, but also tiring and time-consuming…”.
I am not disabled or handicapped person but I am not exactly healthy and fit either. This February I sprained my right elbow when trimming my garden hedge and it took three months to heal. I suffer similar ailments at least every two years so I must be very careful about the way I exert myself physically lest I put myself out of action for months or even years.
Planing pine or spruce to exact square is possible, albeit not enjoyable (not for me). Doing the same with maple, apple wood, or even oak is still doable, but a pain. Doing it with jatoba, black locust or garapa is a penance and for me personally downright impossible, those woods are difficult to cut with chisels, let alone a plane. Not to mention that I might need to flatten also glued pieces and pieces that have the grain running in slightly different directions or even across the grain. Trying to manually plane jatoba across the grain is not as futile as pissing against a hurricane but only just.
Doing one or two end-grain cutting boards manually would be difficult but doable. Making more than that would make me wish I didn’t.
The same goes for lathe. Treadle lathe would kill me doing just a little bit of work. Not to mention that one of the requirements for any tool in my workshop is that it must be comparatively easy to disassemble and store it away when not in use. There are four fixed tools in my shop -- drill press, band saw, belt grinder, and un-bender and I don’t have any more space for a tool to occupy permanently, I would not have any table left to work on.
To be honest, a woodworking lathe scares me even more than a table saw.
For example: https://www.youtube.com/watch?v=PJhI_QweQ0M
and https://www.youtube.com/watch?v=HS0z-AJowwQ
@rsmith, I’m with you on that and if it comes to that, I will be cautious. The second case is why I do not want to span things just between points (although I do that now with my drill-powered lathe) but with a proper chuck on one end. The first one should not be an issue since I do not plan to make hollow forms that could explode. It is unlikely that I will ever turn anything much larger than a wooden mallet.
One thing you might consider is the rotation direction of the lathe.
In the usual orientation, the chisels rest on a support bar. This causes the chips to fly up towards your face. And in case of a mishap, the workpiece will do the same.
If the direction of rotation was reversed, the chips would go down. You’d have to invert the support bar and hold the chisels against the bottom of it. Or maybe use a piece of plate with slits in it to poke the chisels through. If the workpiece were to come loose, it would go down to the bed of the lathe and bounce away from you.