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80K views 27 replies 18 participants last post by  SPalm 
#1 ·
Designing and demensioning

For months now I have looked at other people's homemade drum sanders with the intention of building one myself. About 4 months ago I went out and purchased some MDF to make the discs to stack into the actual drum, but quickly abandoned the whole project when I got busy. Over the last week I decided to start it back up and finally cut enough circle to build a 14" wide drum.
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But then I started thinking to myself "Why just build a drum sander? Why not put a disc sander on the end of it?"
It seems logical to me. The motion is all in the same plane, and it would conserve a lot of space (always a plus). So I went ahead and cut a 12" disc for the disc sander as well.

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I ordered two pillow bearings for a .5" shaft and a 4.5" belt pulley from McMaster Carr which arrived today.
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I'm not sure about the pillow bearings though, I may have to return them. The bearing assembly can flex a few degrees in any direction within the sheet metal bracket. I think one that is locked perpendicular to the ground is what I need.
I am laying it out right now in Sketchup just to make sure I understand the concept of what I want to build. I think I'm going to weld the frame from 1.5" square aluminum tubing to make it light and not too bulky.

I still have not picked up a motor yet, and I'm trying to decide what size to use. I do have a brand new Baldor 1/3 HP, 1725 RPM motor, but I'm not sure it's strong enough. Most other people reccomend using at least .5 HP, and mine might need more to turn the 12" disc sander. Any suggestions?
Here's a quick screen grab from my design so far.
drum-disc sander screen shot

I'm also debating on making a conveyor belt for it like a store bought drum sander has. I have a small slow turning motor that I think would work well, but I'm not sure what to construct the belt out of. Something grippy like the material people put into the bottom of drawers and cabinets, but it would need to be affixed to a strong backing as well. Has anybody else tried this, or why does everybody else go with the "push it through by hand" design?
Suggestions from those of you who have tried or thought about any of this would be great. I'll keep you all updated on my progress.
 
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#2 ·
I've been toying with the idea of the shelf liner as a belt. Most of the industrial drum sanders have it.
I'm also going to put roller bars on the outfeed and infeed side to keep pressure on the workpiece. They wont be motorized, it's designed to do the same function as a featherboard. These are also on industrial drum sanders.

What are you using to raise/lower the table?
 
#4 ·
When you mentioned the idea of a motorized conveyor belt it made me think of the added complexity and I wondered if a hand cranked feed belt would be almost as convenient. That would give you something constructive to do while waiting for the sanding to be done. Unless of course the main motor can perform both functions at once.
 
#5 ·
Prototyping the size

Trying to figure out the size still. I picked up a .5 steel rod at the hardware store and mocked it up a little. I haven't glued the discs together yet or I just wanted to check out the size.

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I've got 24" to work with, which I think will be plenty of space to fit the whole thing except for the disc sander table. That's not a big deal I guess, I'll just make it fold down, so that it will fit in my flip up cabinet.

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I did a little digging around on Mcmaster Carr and found that conveyor belt material is really not that expensive so I think I will try to work it into the design. The motor I wanted on CL got snatched up by somebody else, so I'll have to continue to search.

Here's phase 2 of my design. It's getting complicated, but I'm excited about the challenge. I'm going to try to use a parallel table design raised and lowered by 4 threaded rods that turn in unison with a bike chain.

drum-disc sander 2

My sketchup skills aren't that great, so it's not completely accurate, more of just a rough model. Also, I can't figure out how to draw the belts and chains.
 
#6 ·
This is looking good, more like a production machine. I have a old Makita 2030 that needs its rollers resurfaced.
I contacted a place in Oregon called Western Roller, but never sent them off. I bet the could help you with a first rate set of rollers for this thing, if you plan to use feed rollers. good luck with your challenge. I'm looking forward to following this build.
The idea you have to raise and lower the table will work great cause, thats exactly how my woodpeckers router liftworks you will just need some gears to work with the chain. I wish I had the money and time to take on a challenge this cool.
 
#12 ·
It's getting out of hand.

This did start out to be a simple shop made drum sander but it has mutated into something larger (and a bit of an obsession). I'm having fun just thinking about building it, the question is how well I'll actually be able to replicate my design.
Still haven't located a motor since my last update, but I did mess with the design a little more. I added 4 struts to the table to stabilize it when it's raised and lowered. I found some brass sleeve bearings that should fit nicely and keep it tight.

Drum-Sander Phase 2

I also am thinking about scrapping the conveyor belt idea, and just using power feed rollers (like a planer). Does anybody see any reason for not doing this? I'll just make a stainless steel table top so that the workpiece slides easily once it's gripped by the power feed rollers.
What I haven't figured out is how to link the two rollers since the drum sander will be in the way. I don't really want to get too complicated and add additional belts and pulleys but if I don't come up with a better solution, I might have to.

Drum-Sander Phase 2.1

Another Lumberjock (Sarit) reminded me that I need to add springs to the rollers as well so they compress onto the workpiece. I'll have to make some kind of bracket for that too I suppose.

I know I can make this thing, but the trick will be making the whole thing square and dimensioned correctly. I think it's still small enough to fit into my flip-top cabinet, but if not no big deal.
Right now I'm having plenty of fun just figuring out how to make it. As always, advice from any of you is greatly appreciated.
 
#13 ·
You could put another smaller gear/pulley on the drum shaft and a larger grear/pulley(s) on the roller shafts, to drive the rollers. Not overly complicated, but would work. You would probably need a spring loaded idler to maintain tension, an added complication though.

Good luck. Looking forward to watching your progress!
 
#16 ·
Gathering materials, making parts, prototyping

The last two weeks I've been gathering some of the materials and prototyping some of the parts.
I picked up a 1.125 HP two speed pool pump motor along with a hand full of pulleys and belts for only $22 on Craigslist! I tried to give the guy $30 and he wouldn't take it. What a steal!

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Does anybody know where I can get a custom sander paper belt made? It will need to be about 16" wide x 66".

First I glued up the main drum onto a .5" steel rod. I left the ends long because I'm not completely sure how long I'll need them yet.
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Using 1.75" OD PVC I made the conveyor pulleys. I used a hole saw to cut little blocks out of maple that fit perfectly inside each of the PVC pipes.

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For these I used steel pipe instead of rod. I don't think it needs to be as strong as the main drum.

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I was thinking of putting a layer of rubber on the pulleys to grip the back of the sand-paper conveyor belt and keep it from slipping. Does anybody know if that would be necessary? My belt sander just has hard plastic rollers so I'm thinking the answer is no.

By looking at other people's designs I figured out how to make the mechanism that will put tension on the conveyor belt. Before I spend a lot of time machining aluminum I prototyped it out of some scrap oak this evening. Seems like it will be a pretty straightforward build.

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The 1/4-20 bolt on the end will adjust the tension. The piece that the bearing sleeve is in will slide inside the track.
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This week I'm trying to finish the conveyor table, but I don't think I'll be able to since I don't have one of the sprockets I need yet. I can do the rest of it I guess.

Thanks for looking and any advice you've got I would appreciate. You guys always think of things that I miss.
 
#20 ·
Table assembly

Still working on the drum sander table. Coming along well, though I've broken a few taps and bits requiring me to scrap a couple of parts.
So the table is two pieces of 3/4" MDF laminated together. I glued T-nuts into the sides to hold the side bars.
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One end of the table has a mechanism to adjust the tension on the conveyor belt.
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The side bars of the table are made from 3/8×1.5" aluminum bar stock. I machined the slot out using an end mill.
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The tension is adjusted by a screw on the end that will pull the conveyor pulley backwards.
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I also machined a plate to hold the conveyor motor on the other side.
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Here is the motor hooked up to to the pulley. This is before I found the right sized bushing to fit on the motor shaft so it looks a little crooked. I bought a new bushing from McMaster Carr that fits much better.
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Here is the table mostly complete. The motor is strong but it runs a little slow, about 1 FPM.
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I punched out a couple brackets from some angle iron this afternoon. 4 of these pieces will be mounted to the side of the table and will raise the table with threaded rods.
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I may work on the frame this weekend. I haven't decided on the frame design yet. I'm trying to make sure that whatever I choose, it's not too difficult to change the belt or make adjustments.
 
#24 ·
Frame work 1

I welded most of the frame up this weekend. I'm a beginner welder so it's not great, but it's square and strong enough.
First I welded nuts to the brackets I made last week.
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Then I welded the frame from 1×1 steel tubing.

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I welded some bronze bushings to the frame to keep the threaded rods straight. This was a bit messy since they're impregnated with oil which flushes out and burns black smoke when you weld them.
Here's the one on top…
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And the one on the bottom…
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Here is the mounting for the motor. I'll attach it to the frame this weekend I think.
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Then I shifted back to the main drum. I built a box around it to use as a jig for the router to turn it like a lathe.
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Here it is rigged up with my cordless drill to power it.
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And here it is afterward. It made a pretty good mess too.
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It's getting close to completion. This weekend I'll add the motor mount and the chain tensioner, and chain. A vendor my company works with agreed to make me a 16×62 belt for $24 so I"ll be getting that in a week or two.
Thanks for looking, any advice is welcome.
 
#25 ·
That's really coming together very nicely!

COOL jigs!

Thank you for taking the time for pics.
 
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