I had been wanting to make a sanding drum for some time. Sanding by hand we all know that it is a nuisance. And when we buy our first electric wood sanders, we usually buy sanders that serve primarily to sand flat surfaces.
Not long ago we saw how to make a disc sander for drill, which apart from sanding edges also serves to sand external curves. So in this post we are going to see how to make a sanding drum to sand internal curves with the column drill.
This is a carpentry project that surprised me with how easy it was to carry out. In addition, it is also surprising how easy it is to sand with this wood sander.
So to make the sanding drum I have to cut the circular pieces that will form it. In this case I use a 60mm diameter core bit to cut 5 plywood discs 14mm thick.
Although I decided to take advantage and cut 10 pieces to make two sanding drums. So I can put two different grit sandpaper: 120 grit sandpaper and 320 grit sandpaper.
And now it's about sticking 5 discs together with an 8mm threaded rod that runs right through the middle. To do this I first have to drill an 8 millimeter hole right in the center of each disc. And it is that the centering bit of the crown bit is somewhat smaller than those 8 millimeters, so I had to re-drill that hole.
The plywood table on which I cut the discs bears the mark of the crown bit, so I avoided moving the table and it helps me to center the plywood discs so that I can drill right in the center with the 8 mm bit.
So to mount the sanding drum:
- I put a self-locking nut on the threaded rod.
- I applied epoxy resin and stuck a large washer against the self-locking thread.
- I applied epoxy resin on the washer.
- I put the first disc against the washer.
- I was applying carpenter's glue and gluing one disk on top of the other.
- I applied epoxy resin on top of the last disc and put a large washer on top.
- I applied epoxy resin on top of the washer and stuck a nut against the washer.
- And with two wrenches I tightened both nuts with force so that the excess glue came out between the plywood discs.
- I cleaned the glue and let it dry.
So I already have the shape of the sanding drums, although the surface leaves a lot to be desired. But with a sandpaper attached to a piece of plywood board and the help of the metal column of the drill press, I can grind the drums.
We can see the difference between sanding and not sanding in the photo in which I show the two sanding drums.
But in order to use this as a wood sander, I have to put a sandpaper on it. And the easiest thing I could think of was to cut a vertical slot with the handsaw. Well, easy was not easy either, since holding well with some carpenter sergeants the sanding drum was not easy. But in the end I managed to cut the slot.
The width of the groove is just enough to fit one end of the sandpaper. And the sandpaper is glued with stencil glue. You have to use a somewhat strong stencil glue and we have to make sure that we roll the sandpaper in the opposite direction to the direction of rotation of the sanding drum.
Now I can put a bearing on the bottom end. I chose a bearing 3 centimeters in diameter. I put it against the self-locking nut and put two nuts on the other side so that they lock between them.
The bearing bore is slightly larger than 8 millimeters, so to keep the sanding drum from rolling off-center I left it a little loose between the nuts.
I'm also going to need a sanding table. Well, a table on which to rest the pieces to be sanded while using the sanding drum as a sander for wood.
As seen in the image, it is not difficult to do. I just stuffed a couple of bolts into a small plywood board and screwed another small board on top. The bolts are set so that they fit into the grooves in the metal table of the drill press.
So I can hold this table with washers and wing nuts, just like when I made this drill press a drilling table with lateral guide.
Now I have to screw another slightly larger board on top and drill the necessary holes to fit the sanding drum. With a 68 mm crown bit I was able to drill the top board. And with a 3 cm diameter cup bit I drilled a hole to fit the bearing.
And so far everything very nice, but after a while using this wood sander without any problem, suddenly a few days of very hot weather came and the sandpaper started to peel off when turning in the drill press. Although after some tests I found a simple solution that works perfectly for me. If you want to know what it is, don't miss this video:
As you can see, a very simple solution with a bit of double-sided tape.