Home made drum sander

[Cherryville Chuck]

I started building a drum sander last fall, got sidetracked with other jobs, and finished a couple of weeks ago. It works fairly well. I had seen others make drums from mdf discs so I bought a 4 1/8" hole saw to make them with. For the arbor shaft I bought a 3' length of 3/4" keyed shafting. I should have gone to 1" but I thought 3/4 would be enough for a drum about 12" wide. It's ok but 1" would have been a little better.

To cut the discs I clamped pieces of mdf to my DP table and then used a 3/4" hole saw to cut the hole for the arbor and then the 4 1/8". By clamping the mdf to the table I stayed centered. To cut the keyway in the discs I slid them on the end of the shaft and made pencil marks for the sides of the key channel then a couple of saw cuts with a keyhole saw and then using a sharpened piece of key stock I hammered the key through. Except for a bit of blowout on the far side, the slots for the key were fairly clean. When it came time for gluing the discs together I put the key stock in the channel put glue on the discs and kept sliding them onto the shaft until they were all on and I could clamp them together.

In making the frame I clamped both sides together and drilled all the holes through both at once to make sure each was a mirror image of the other. It took me a while to think my way through a method for height adjustment. I wanted the table to stay in a fixed relationship with the drum during adjustment. I finally figured out that the best way was to hinge one end so that it stayed fixed from one side to the other. The first photo shows the screw for height adjustment. I drilled and tapped a cross dowel and inset it into the cross member to finish that out. I also slotted the sides of the frame and put knobs through to the frame of the table to lock it in position.

Once that was all done I glued a piece of sandpaper to a sloped block of wood and started the motor and ran the paper back and forth under the drum until the block passed through from side to side. A bunch of coats of varnish and then I used some self stick sandpaper roll to wrap the drum. So far it's holding on okay. If that gives me trouble I'll try gluing the cloth backed roll type onto the drum using fish glue.

Drum sanders need dust control so I added a plenum over the drum and piped my DC to it complete with blast gate. The brackets on either side of the drum are both for structural integrity and help form the plenum. I added some spring loaded hold down bars onto the brackets that use some 3/4" x 3/8" UHMW strips meant for miter slots. The motor I'm using has been hanging around my shop for years. I don't remember where it came from. Maybe an old washing machine. For now I'm using an air switch I got years ago from Lee Valley. It sits on the plenum right in front of where I have to stand to operate the sander. I may just stick with that. It seems to be a pretty good arrangement so far. Those switches are handy for routing and using a DP too when you need both hands and still be able to turn the machine off and on.

This machine is strictly manual. Push the wood into one side and pull it out the other. As a result you have to stand in the middle of the side to do that. I won't bother guarding the motor, drive pulley, or belt because with the DC hose coming out that side too it's impossible to operate it from that side. I do need to guard the end of the arbor on the other side still. I'm pleased with the job it does so for the roughly $200 it cost me to make it I think it was worth it.

[Herb Stoops]

Pretty neat sander. When you raise/lower the table, is "in" board end fixed and the "out" board end adjustable?
Do you experience any kick back when feeding material through?
I like to see homemade power tools, I think the more you use it the more you will revise it too.
Herb

[Cherryville Chuck]

It's the inboard side that is adjustable and the outboard end fixed. It will push the pieces back out if you let go but I haven't had any shooting back. But maybe that's because I'm only taking a few thou off, enough to get rid of saw marks and you gauge the resistance as you push the piece through. Maybe one of the advantages of not having a powered bed like the manufactured machines have.

[Herb Stoops]

Do you use the weight of the motor to tighten the belt?
How is the hood over the drum attached?
Herb

[Cherryville Chuck]

Yes, the motor is bolted to a door hinge. You may be able to see it wrapped around the frame in the photo. The hinge was already bolted to the motor and I left it on so I think this must have been my FIL’s motor and I inherited it. The dust plenum just sits on the frame. It’s the same dimensions and same ply as the structural supports so all I did was add strips around the inside to keep it in place.

[DaninVan]

Lol!...not Baltic Birch then?

[Cherryville Chuck]

This 5/8" fir was expensive enough. Plus the only source I have for it here only sells it in 1/2 thickness I think and I wanted it a little thicker than that.

[DaninVan]

I was kidding, Charles; every time I see one of these DIY drum sanders (on YouTube esp.) the authors INSIST you're wasting your money unless you use Baltic Birch. Didn't the US use D.Fir plywood to build their PT boats in WWII?

[Herb Stoops]

1.Chuck,it looks like the large drive pulley only has a 1/2' shaft, how did you reduce the drum shaft down for the pulley?
2.Was the pulley one you had on hand ,or did you calculate the rpms of the motor and reduce them to a certain rpm for the drum? I suppose the motor is a 1/4hp., 1720 rpms? So the drum runs around 800 RPM's?
3.Since the table is basically fixed on one end, what would be the max thickness of the material you can sand? Is there a minimum?
4.For example you wanted to sand a small item,you make a sled to hold it,and your limited to the height you can sand, can you adjust the fixed end of the table to gain some height?
HErb

[Cherryville Chuck]

I was kidding, Charles; every time I see one of these DIY drum sanders (on YouTube esp.) the authors INSIST you're wasting your money unless you use Baltic Birch. Didn't the US use D.Fir plywood to build their PT boats in WWII?

I knew you were but I wasn't. The guys that insist on using baltic for every project and jig must have deep pockets. Good chance you're right about the PT boats. You and Stick and Herb probably know better than I do but wasn't pine and spruce lumber kind of shunned by carpenters way back? If I'm right then that attitude would have applied to plywood too. Also the Aussies were building airplanes out of 3 ply during WW2. Pretty sure it wasn't baltic birch either.

[Cherryville Chuck]

1.Chuck,it looks like the large drive pulley only has a 1/2' shaft, how did you reduce the drum shaft down for the pulley?
2.Was the pulley one you had on hand ,or did you calculate the rpms of the motor and reduce them to a certain rpm for the drum? I suppose the motor is a 1/4hp., 1720 rpms? So the drum runs around 800 RPM's?
3.Since the table is basically fixed on one end, what would be the max thickness of the material you can sand? Is there a minimum?
4.For example you wanted to sand a small item,you make a sled to hold it,and your limited to the height you can sand, can you adjust the fixed end of the table to gain some height?
HErb

Sorry for the long pause before posting this. I was almost finished with my reply and a windstorm knocked out the power.

1. The parts were all things I had on hand, except for the bearings, keyed shaft, and the sheet of ply. Stuff like pulleys I keep around cause you just never know and I do have a fair bit of storage space. The big pulley has a 3/4" bore to match the shaft.

2. There was a pulley already on the motor. I think the motor is either 1/2 or 5/8 hp. I didn't know if that was going to be enough power but it's fine for the speed the drum turns at. I do have a 3 hp 3450 Baldor sitting around that I bought years ago and never got around to using but it's big, heavy, and too fast so I was hoping not to need it. I'm not sure what the drum speed is, I can't remember if I ever did the calculation. Maybe 1000 just guessing, but 800 would be a reasonable guess too. I could go measure it. I have one of those old manual Starrett revolution counters. I didn't want it too fast as I think that would cause lots of problems like burn the wood and exacerbate vibration if the shaft was out of balance. It was mostly just me throwing parts together and see what it produced and then make alterations if needed. The only alteration I made after the initial tryout was to add some spring loaded pinch bars to hold the pieces down for better sanding accuracy. Otherwise I got lucky and it's good enough the way it is.

3. The max height is between 3 and 4". Minimum is right at touching the drum. Because the one end is fixed that means you are pushing uphill with thick boards and downhill with thin ones. So far all I've run through it are the roughly 3/8" thick pieces of birch shown in one picture. I had a lot of birch at one time and I started making parquet flooring out of some of the knottier pieces to do part of my house. I gave up when I realized I probably wasn't going to live long enough to cut that many pieces. That's a process that needs mechanizing. For years I've wanted to make a wooden bow and some of the laminations in a wooden bow are tapered from the handle to the tips and this type sander would make that possible if you attached it to a tapered board.

4. There is no adjustment for the fixed end but I'll use it for a while and see it winds up being necessary. I do have a plan if it needs it. The only reason I would do it is if the table moves from being coplanar with the drum (it shouldn't). I think I have enough range of movement to satisfy any job I would use it for. As for thin, I'm not sure yet what is too thin. At some point I would guess that a piece would start to flutter under the drum and cause gouging (or get caught and explode). Then it would need to be on a sled. I think it'll be okay down to about 1/8". Any thinner than that and I'll probably want it on a sled anyway as that will be getting too close to the drum.

[DaninVan]

I was kidding, Charles; every time I see one of these DIY drum sanders (on YouTube esp.) the authors INSIST you're wasting your money unless you use Baltic Birch. Didn't the US use D.Fir plywood to build their PT boats in WWII?

I knew you were but I wasn't. The guys that insist on using baltic for every project and jig must have deep pockets. Good chance you're right about the PT boats. You and Stick and Herb probably know better than I do but wasn't pine and spruce lumber kind of shunned by carpenters way back? If I'm right then that attitude would have applied to plywood too. Also the Aussies were building airplanes out of 3 ply during WW2. Pretty sure it wasn't baltic birch either.

Canada also; the Mosquito Fighter Bomber..

[Herb Stoops]

I loved those old WWII planes!
Herb

[DaninVan]

I loved those old WWII planes!
Herb

Which ones did you fly, Herb?

[Herb Stoops]

Just wish it were so, the farthest I got was a Army reconnaissance Piper Cub. the 3 point landing one.
Herb