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I'm getting ready to build my own drum (thickness) sander. My questions are as follows:

1) I have a piece of 3 1/2" aluminum tubing 24" long that's been donated to me for next to nothing if I want it. I like the price, but I'm concerned that the diameter is a bit small and that I'll be changing paper far more often than I should have to. I have a 3.25 hp motor and I figured I'd might as well take advantage of it by using a 5" or 6" drum. Will it make much difference, or am I worried about nothing?

2) I've noticed that a lot of you use the velcro hook and loop style of sandpaper. I want to be able to sand tops down to about .020" to .030" for making nomex-cored double tops. It seems to me that you'd lose a lot of the accuracy of the drum this way. I'm sure it dosen't matter if your bringing tops to the regular thicknesses, but with the thickness I'm trying to sand to, I think I may be better off fastening the sandpaper on another way. Any suggestions/comments would be greatly appreciated.

Thanks

Clint

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-Clint Beacock

Clint, I think you'll find answers to both questions in past discussions & archives. (Maybe search MIMF too.) From what I recall, 3 1/2" should be fine & don't use velcro, for the reason you state (but that advice is worth exactly what you paid for it, since I haven't built one a s yet.)

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Dave
Milton, ON

Clint…a 3 ½” drum will work nicely. There are some advantages to using a larger drum but at that rate I would build a belt sander with the 3 ½” drum.
Are you planning to build this machine out of steel or wood?
I am tiring to get a since of what your resources for machinery and materials are like.
In any event it sound like fun I’ll help you as much as I can.

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Rich S

"The inconvenience of poor quality will linger long after the thrill of a bargain has been forgotten"

Use the largest shaft and bearings you can get your hands on. I thought I'd be okay with 5/8. Wrong. Actually, I'd recommend keeping your eyes on Craig's List. I've seen several double drums and wide belts selling for ~1000, and picked up an almost new Delta for 300.

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Gabriel Regalbuto
Carlsbad, California
Freedom 35!

Thanks for the input, guys.

Rich, I'll be building out of steel. I'm a tool and die maker/machinist so I have easy access to anything I'll need, except for a 5" drum so far. Should I use the adhesive backed sandpaper?

Gabe. Thanks for the tip. I'll be using 1" Thompson shafting to drive it so that shouldn't be an issue. I'd love to just buy a sander, but I can't justify spending the money right now. I've gotten everything but the motor for free so far, and that was a pretty good deal.

Plus, I guess I kind of like building things myself. Just wish I had more time for it cause these things can really drag sometimes.

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-Clint Beacock

We might want to compare notes... I am going down a similar path.

Mike

Sounds like you've got the skills to get the job done right (I didn't). Don't mean to point you back to the buy vs. build direction again, but drums are available as replacement parts from Grizzly if you are so inclined.... That was my next move before I lucked out on the Craig's list score.

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Gabriel Regalbuto
Carlsbad, California
Freedom 35!

Hey, I am also a tool and die maker thinking about building a drum sander. You might try searching ebay for rollers. I have seen some interesting prospects in the business and industrial section.

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Jeremy Vonk

Here's my experience for what it's worth: I built a drum sander with a 6" drum that I made out of 25 stacked wood disks cut from 3/4" MDF. The hinged table under the drum is made from two 3/4" plywood pieces glued together topped with smooth wood flooring.

At first I used "regular" sandpaper that I held on to the drum with two-sided tape on the ends. Worked not too bad but I found the two hard surfaces, i.e. the drum and the table were a little unforgiving and tough on the wood - more so with the finer sand paper. A had a couple of pieces develop cracks on their ends from pushing them through the sander. Then I switched it over to a hook and loop system and I find it works better. Aside from the increased ease of changing over the sand paper, I think the hook and loop system provides a little cushioning that helps. This may not be as important if the design you have in mind includes a table with a little give to it. As for ability to take a little off at a time and sand thin, I have had no issues and can sand in a very controlled manner. In short, I have no hesitations in recommending the hook and loop approach for home made drum sanders.

Pat

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There are three kinds of people:

Those that make things happen,
those that watch things happen,
and those that wondered what happened.

Thanks for the advice, Pat.

I'd read that the 'cushion' provided by the hook and loop system was one of it's advantages. Since you built out of MDF, I've read that it's definitely the way to go, because the cushion results in a lot less heat build-up. The ease of replacing the paper would be another.

I really have zero experience with it so that's where my hesitation comes from. My machine design will likely include a couple of dial indicators at each end for micro adjustment, so end to end I'll be able to get dead on. What I'm worried about, is whether I'll be able to hold a flatness tolerance of about .005" with this system, since I'll basically be sanding my tops into veneers.

Sometimes I think that I have to learn to tone down my expectations for tolerances when working with wood, but wanting everything near perfect gets kind of engrained in you in my line of work.

I appreciate all the advice I've gotten, and continue to get on this forum. It really is a great resource.

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-Clint Beacock

Clint…I have a mission (idea) for you if you chose to accept it.
I have been contemplating building a surface sander that functions much in the same manner as most drum sanders with the exception of the conveyer table. Instead of a wide belt to feed the wood under the drum, I would replace it with a vacuum table that would slide back and forth on linear rails.
The sanding drum would have a positive stop set for the final thickness and springs that would allow the drum to rise up as the wood is passed under the drum. With each pass the drum will remove material until it hits the stops.
Another feature to add would be to blow high pressure air along the drum to clear the sandpaper of dust.

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Rich S

"The inconvenience of poor quality will linger long after the thrill of a bargain has been forgotten"

Why so big a drum?

Mike

The larger the drum, the better the dissipation of heat along with an increased length of sanding surface but with a larger drum you will also increase the surface feet per minute. In order to slow things down you will need to have a gear reduction which will negate any chance of a direct drive. The increased complication of a belt drive may or may not be worth the effort.

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Rich S

"The inconvenience of poor quality will linger long after the thrill of a bargain has been forgotten"

Hey Guys,
My experience has been similar to Pat's. I built my sander over 10 years ago mostly from salvaged materials. It has a 16" diameter stacked MDF disk drum driven by a 5 HP motor I rescued from an air compressor. The platen is 2 pieces of 3/4" MDF covered with stainless steel and rides on a welded steel frame that is adjusted via the chain loop crank. A gearmotor powers the infeed and outfeed rollers that are nothing more than 1" shafting that I had knurled at the machine shop. I initially wrapped the abrasive directly on the drum untill I tried the hook and loop. The hook and loop works better for me. It has served me well. It sands within .005" across the 16" width everytime. I wish I would have made it wider though.

Kent

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Kent Schoonover

WWW.schoonoverresophonicguitars.com

Kent…that’s one cool machine you built.
I love the raised letter “Sandie” on the frame and it is appropriately named. Did you use a welder to do it?
Do the drive rollers leave knurl marks on soft woods?
How thin can it go?

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Rich S

"The inconvenience of poor quality will linger long after the thrill of a bargain has been forgotten"

Thanks Rich,
I did all the welding with my mig. Yes, the name is welded bead. The outfeed roller does leave a faint cross hatch pattern on spruce and cedar, but it is no worse than 80 grit sanding marks. I wish I could tell you the size of the knurling. I am sure if you went too course it could be a problem. My machinist buddy recommended the size I went with.

Kent

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Kent Schoonover

WWW.schoonoverresophonicguitars.com

Clint et al,

I don't want to discourage anyone from building a Cadillac - if you have the tools and the talent go for it, but I can't help feeling that a Volkswagen will do the job just fine. Here are a few pictures of the sander I built:


This first one shows the drum with the disks as yet un-trued (which I did by running it against sandpaper on the table). The photo also shows the drum and motor pulleys and the big bolt I used to raise and lower the table.


This second image shows it assembled with the drum trued.


This third image shows it with the dust hood in place. My shop vac fits in the top. Not sure why I felt the need for a window but there you go.

I don't have any pictures showing the hook and loop modifications.

All in all, pretty simple and it does the job just fine. Normally what I do is make quarter turn adjustments while I'm thicknessing wood. At each adjustment I push the wood through 2 or three times. Naturally, with each push on one adjustment, less wood is being removed with that pass. I track my progress with calipers. You quickly get a feel for how things are progressing with the board you are sanding, the grit of paper you are using and the adjustments and passes per adjustment you are making. I don't think dial indicators on the machine itself are going to help you much with this. It's better to keep measuring the wood. Doing that, fine control is not difficult.

Pat

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There are three kinds of people:

Those that make things happen,
those that watch things happen,
and those that wondered what happened.

I like your design... it is very close to the one I am building. I will be using a hinge mechanism that puts the weight of the motor on the belt. Have you thought about that?

Is the shaft keyed? What diameter shaft? How did you lock the disks in place? I was thinking of using mini-hubs for sprockets (go-kart).

I think I will true the cylinder on a lathe also. Heard bad stories of paper gapping because one end was smaller than the other. The shaft I am using is 24" long, 5/8" or 3/4". Keyed.

Also, I have heard people complain about "valleys" because there is no autmated belt feeder...

Mike

Wow. A lot more response to this thread than I was expecting. It's always helpful to get, and see, other peoples ideas and machines they've built.

Rich, I hadn't given much thought as to incorporating a power feed, but funnily enough, I was planning on building a vaccum plate of sorts into it, although more of a downdraft table for dust control and keeping the part flat. Your idea is interesting, but I think it might be difficult to find a spring pressure that'll be aggresive enought to take the wood down, and light enough to allow easy lifting as you pass the piece through it. I think light springs would allow too much vibration.

I'm thinking of having the drum held up by spring pressure for the fine adjustments, but I'm planning on using a couple of nitrogen gas springs at about 200 lbs pressure each.

Your idea has got my wheels turning, though.

Thanks for the input.

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-Clint Beacock

Mike,

The motor does indeed sit on a hinged board so that its weight provides the tension in the belt. The shaft is 3/4" pipe from Canadian Tire. It is not keyed. I did worry about how I was going to lock the disks in place but it turned out that I had to hammer the pipe pretty hard to get them on and it didn't take me long to realize that there was no way that they were moving once glued together to become the drum. Truing the drum on a lathe will reduce the amount of sanding against the table you will have to do but I don't think that step can be replaced. Nothing like truing it up in-situ.

It is true that if I let a piece of wood sit under the drum it will create a valley. Good to push at a steady speed. I never considered this as a tool to get my final surface. I consider it a tool to thickness to very close to final and I finish off either with my random orbital sander or by hand.

Pat

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There are three kinds of people:

Those that make things happen,
those that watch things happen,
and those that wondered what happened.

Well, some of you might be interested in this. The valley problem concerns me. I think Pat has an excellent design... I had not considered that the combined frictional effect will hold it into place, still, I am going to use two locking collars with through bolt holes to screw into the end of the cylinder (mcmaster). I will also use a solid steel rod from mcmaster. (hey, I am a mechanical engineer). I really like the idea of the large drum size. This will help with cooling and increase time between paper changes (hook and loop). BTW, anybody got a good source for the hooked part with adhesive? I have not found that yet.

I found an excellent (cheap!) source for 1.5 inch diameter rubber rods (3/8" aluminium rod with rubber roller, 19" long. I am going to combine that (two of them) with a sprocket and chain plus a high torque, low rpm motor (think rotiserie) to create a constant feed conveyor. I will post parts if anyone is interested. Plus, I am using a press screw from mcmaster for the height adjustment.

Pat, please post dimensions of your base.

Thanks,

Mike

Mike,

The dimensions of my table under the drum are 20" wide by 24" deep. I hope that is enough to give you the idea of size.

My source for the hook part of the hook and loop - as well as the sandpaper is use is here:

http://www.stockroomsupply.com/Hook_and ... ersion.php

Click on the information for hook and loop conversion rolls at the bottom of the above page.

Pat

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There are three kinds of people:

Those that make things happen,
those that watch things happen,
and those that wondered what happened.

OK. But I have studied their design. The "flat master". Do not like it, but maybe their hook & loop is usefull.

Mike

I don't know about the Flat Master, but their V Drum Sanders are great. I have seen them work, and they work great. No adjustments, no heat, no dust, no static, no burning if you stop the wood, no gunk in the sandpaper, and the finish is smooth as a baby's behind. They are not, however, thickness sanders. But neither are the drum sanders everyone is using for thickness sanders, in reality. Other tools are really designed for thicknessing.

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Waddy

Photobucket Build Album Library

Sound Clips of most of my guitars

WaddyT

Besides hand tools, what are you refering to?

Mike