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Combo Drum Sander #2: Thickness reducing sander

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Blog entry by tyka posted 1266 days ago 5171 reads 28 times favorited 11 comments Add to Favorites Watch
« Part 1: Concept and making the drum Part 2 of Combo Drum Sander series Part 3: Surface Sander, cabinet, specs, cost, observations »

Hi folks. After some design changes and fine-tuning the drum sander is finally completed. Here’s a point by point description covering some of the steps I feel important to take on this project. Pictures should help where I’m not so clear. I will post the surface sanding option, some dimensions, and final comments in Part 3. Here it goes….. hope you like it.

Main Body: Made with ¾” maple veneer plywood and solid maple for the pillow block base. Assembled first with pocket screws to check the design (without a bunch of clamps in the way) before everything was glued together with TiteBond III (the only glue I had at the time).

Everything was finished to varnish grade but decided to use enamel paint for most parts. I thought it might look more like a tool this way. Red was used for the dust cover and the belt/pulley cover to remind me of the safety hazards.

Access to the pulley, belt, and the motor is through a door-like cover held closed with a rare earth magnet.

A small drawer stores sanding belts, notes, etc. The table is made with two pieces of ¾” plywood laminated together; Formica covers the top surface and the sides are finished in Birch. I was fortunate to get a large piece of Formica (32” x 12’) for free from our local cabinet shop. It took me a while to get the guts to go because it’s a large high-end manufacture. Well, you never know unless you ask….. so they say!

The front micro table height adjustment is controlled with a 3/8” threaded rod, knob, and a wing nut to lock it. Under the table, the threaded rod is screwed in a ½” rod that swivels on two ½” copper straps.

The back height adjustment is controlled with two knobs and runs smoothly on a nylon runner.
I over-tighten the screws on the nylon runner just a bit to get a “micro-swell” to create a very snug fit without any side play. Important: The piano hinge has to be aligned perfectly with the sliding piece; otherwise the table will not be parallel with the drum. I found this out the hard way.

Pillow Blocks: The pillow blocks are held in place with 3/8” bolts attached to cross dowel quick-connect hardware. They are strong, and can be dismantled easily as often as needed without weakening the anchoring system.

A simple tool was used to keep the 3/8” bit straight and centered in the ¾” plywood side.

The dowel holes don’t have to go all the way through therefore preserving the exterior finish. I couldn’t find cross dowels locally so I made some with a ½” bolt. A bit of work, but better than taking a long drive to town.

Motor: The drum sander is powered with a 1 hp general purpose motor running at 1725 rpm. 2”diameter pulleys maintain the speed of the motor. The link belt works well; it was a bit expensive but makes the sander run smoothly without any vibrations.

I found the motor too heavy for 1” piano hinges. The hinge was twisting making the motor run on an angle. I made a motor-mount with left-over router parts and angle iron.

The motor is anchored to four ¼-20 T-nuts on ¾” plywood

Dust Cover: The dust cover (3/4” plywood) is close to the drum (+/- 1/2”) to capture as much dust as possible with a shop vac or dust collection system. It covers the drum, pillow blocks and the drum pulley. It’s fast and easy to remove; locks into place with a knob in a slot on the left side. I thought I would need something else to hold it on the right side (a magnet maybe) but its heavy enough and doesn’t even vibrate when the motor is running. Clear Plexiglas (3/16”) provides a visual of the drum, pillow blocks and pulleys. The 2.5” dust port is centered but more towards the front where dust should be more concentrated.

Final touches for the drum: The drum was made smooth, true and parallel with the table with 80 and 120 grit sand paper glued with two-way tape to a piece of MDF before installing the fences. A dial gauge showed a variation of .003” along the length of the drum mostly in the center. I will have to live with that LOL

The MDF discs were sealed with a mixture of glue and water. One part water 3 parts Titebond III and re-sanded with 320 grit sand paper. I tested the sealed MDF by sticking two-way tape on it and was surprised how well it was sticking. That part worried me a little because of the cost of the Velcro. I liked the idea of using epoxy but it was beyond my means. In any case the glue will never come off and it sealed the MDF with only one application. I tried a second coat, but it was not penetrating at all.

Applying the drum Velcro: The Velcro matting angle was calculated by wrapping a string around the drum to get the circumference. This measure was then transferred to the Velcro as shown in the picture. Then I applied the Velcro tape all the way to the end (without removing the paper) to find the exact place to angle-cut this end. The same procedure was used for the sand paper.

First Test: My first test was to sand a 3/8”x 6” very rough wood plank with the 120 grit sand paper. The sander took it down to 5/16” with about four passes. At this point I am confident enough it will perform well. Of course future sanding of doors and project parts will be the real test.

The board was very smooth and a square showed it was parallel, even and flat across the width. Then I had the pleasure to use the sander to sand the table fences. LOL

Here’s other pictures that might help.

Hope this will help LJ’s wanting to build one of these. Send me any questions you may have. Thanks for looking

-- Paul, Plantagenet, Ontario



11 comments so far

View Splinterman's profile

Splinterman

23058 posts in 1996 days


#1 posted 1266 days ago

Hey Paul,
Good strong construction and functional design which will serve you well for a long time….nicely done.

View johnzo's profile

johnzo

70 posts in 1430 days


#2 posted 1266 days ago

Nice job! I built one last year and I use it almost every day. You’re going to love yours!
John Z

-- 70 is the new 50!

View BigTiny's profile

BigTiny

1664 posts in 1523 days


#3 posted 1265 days ago

Hi Paul.

Nice job. I intend building one of these, but will make it an accessory of my lathe. That will save me having to build a base and from having to buy a motor. ll I’ll need to make is a drum, a platform and the adjusters, plus a way of holding it all on the lathe.

Paul (the other one)

-- The nicer the nice, the higher the price!

View mainwoodworks's profile

mainwoodworks

112 posts in 1283 days


#4 posted 1265 days ago

Hi Paul,
I have a Delta 31-255X Drum sander. I work on it about as much as I use it. Have replaced the miter gears twice now ( made of plastic). It took me forever to get the conveyer belt to run straight. The belt grabbers that hold the sandpaper belt broke and it just goes on and on. When it works it works well but that is not often enough. My hat is off to you for the job on your sander. Sense it does not have a conveyer belt, do you just push the material through and does it tend to kick back at you? I may have to look at building me one like it.

-- Measure twice, cut once, and hope for the best.

View tyka's profile

tyka

141 posts in 1327 days


#5 posted 1265 days ago

Paul,
Using your lathe is a great idea and a money saver. If the drum is free from pillow blocks (cantilliver) at one end you will be able to sand wider pieces with a fairly short drum. I would like to see it when you get it done.

Mainwoodworks,
Sorry to hear about your problems with the Delta sander. It must have a cost a few $. A conveyor belt would be nice to maintain constant feed speed. I haven’t had any kick backs even when I challenged the 1 HP motor to stall and couldn’t. I use the push stick every time except when I did a test by sanding only one end on the rough board (pic) by going back and forth. Safety is important to me, so I stand to the side just in case it happens.

-- Paul, Plantagenet, Ontario

View thelt's profile

thelt

618 posts in 2014 days


#6 posted 1247 days ago

Paul, Very nice. Looks like it’ll do the job nicely!

-- When asked what I did to make life worthwhile in my lifetime....I can respond with a great deal of pride and satisfaction, "I served a career in the United States Navy."

View stefang's profile

stefang

12953 posts in 1968 days


#7 posted 1247 days ago

You did a great job on this Paul. From your description of the details I’m sure it will give you excellent service and few problems. Thanks for sharing you ideas with us.

-- Mike, an American living in Norway.

View AttainableApex's profile

AttainableApex

338 posts in 1467 days


#8 posted 1244 days ago

very nice

-- Ben L

View Chefshep's profile

Chefshep

121 posts in 1317 days


#9 posted 1239 days ago

Paul

Kudos on this one!!! great job!!!

-- Chefshep :) "When we allow our present to quarrel with our past, we risk jeopardizing our future.” - Winston Churchill

View ecurb's profile

ecurb

2 posts in 926 days


#10 posted 919 days ago

Paul,

Thanks for the inspiration. I just sealed my MDF drum last night and must say that the 3:1 mix worked out great. Your sander turned out great, hope mine can come close to being as good.

-Bruce

-- -- Bruce, Iron Rod Woodworks.

View tyka's profile

tyka

141 posts in 1327 days


#11 posted 919 days ago

Bruce,

You are so welcome. It’s a good feeling to know I can give back this way. Call on me anytime you have questions.

Paul

-- Paul, Plantagenet, Ontario

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