Thread: home made drum sander

OK I have one which I built which is 120cm wide so I can tell you the issues you face as there's pitfalls you dont think of. First I bought a bright steel shaft about 20mm and two pillow bearings then off to the Reece and got a lump of PVC pipe. The size of the pipe matters the bigger the better but it costs more in paper so dont get carried away. Then I got my router and any bit of chipboard I could lay my hands on and, made a jig to cut slightly larger circles than the pipe and produced some of those, Bought a motor off Ebay (2HP) and got a V belt pulley just smaller than the pipe and fitted it to the shaft and a wooden disk. then fitted the rest of the disks. Fitted the bearings to a frame and started the motor, with the shaft spinning I then filed the disks to a nice snug fit in the pipe. Sandpaper, I thought would need to be securely glued, not so all it needs is well tagged at the ends. You can also join it if the paper can peel from a front sand and a backing paper but look at the way you wind it so that its getting tightened when the wood is pushed in and the drum is pulling, dont get the paper too wide 4cm is about correct. My idea was to have the roller coming through a slot cut in the old kitchen table so that the work travelled over the table. That doesnt work. Next I made a top under the roller and adjusted that up and down with four lengths of threaded rod. that works. Now I was doing redgum benchtops which are heavy My next issue was holding the wood whilst sanding. This I achieved with a sheet of yellow tongue as a very long table and then fitted casters to the underside of the bench. My next issue was whilst sanding the drum hit an harmonic and started to vibrate, almost shook my teeth out. What I had to do was strip the drum apart and cut more disks and glued them till I had a complete wooden roller then place the pipe on that. Oh the pipe idea is to be able to have another with a differend grade of paper etc. Also when you glue the sandpaper to the pipe, when changing parer it cleans off easy. My if I built it again would be, more power with perhaps a double belt pulley. I used weldbond to glue the paper, why, because it sets faster. good luck. Failings are if you get greedy it will mess up, I would turn the nuts on the threaded rod ¼ of a turn then pull the wood back and forth about 10 times when nearing a finish. Rob

Rob how do you stop the pipe spinning on the wooden drum?

Thanks rrobor.

I had thought of some of the issues you listed.

How fast does your drum spin?
How many poles is the motor?
At 1200mm in length, does the drum remain true when spinning or is there deflection?

What color are your socks and are you regretting replying yet??

Oh yeah, and what glenn k said as well.

I have tried adding some pics and "engineers" drawings of my conceptual go kart.

Pic 1 - artists conceptual image.
http://i787.photobucket.com/albums/y...ander/Pic1.jpg
Pic 2 - outlines basic design and location of drum and feed rollers.
http://i787.photobucket.com/albums/y...ander/Pic2.jpg
Pic 3 - outlines basic design of material bed and adjustment system there of.
http://i787.photobucket.com/albums/y...ander/Pic3.jpg
Pic 4 - paper fastening method, derived from "jet" and "store-shorthand" design.
http://i787.photobucket.com/albums/y...ander/Pic4.jpg
Pic 5 - Pic of feed roller design from here.
http://i787.photobucket.com/albums/y...ander/Pic5.jpg
http://www.mimf.com/library/tamayo_feeder_assembly.htm
Pic 6 - Pic of bed adjustment design from here.
http://i787.photobucket.com/albums/y...ander/Pic6.jpg
http://www.mimf.com/archives/thickness_sander2.htm

I was thinking I will fix swing up table tops to the in and out feed sides of the material bed so as to increase the support without increasing the storage area required for the machine.

The feed rollers seem simpler than a convey belt feed system to suit 1200 wide and I think it should minimise kick back.
If I can get them close enough to the drum, depending on their diameter, the minimum capacity of the machine should be close to that of the jet machine.

I am assuming at this stage, that the solid drum is the preferred method of choice.

Out of interest, an "improved version" perhaps of the shop notes sander is here http://www.woodworkstuff.net/EDTSander.html

Hmm... I seem to have used orange text twice??

This sander has been made with walnut for the drum discs to reduce the weight.

Thanks again for the input.

As a weekend hack, I'm dangerous enough with well designed and manufactured equipment... boy I can't wait to get my hands on this baby.

Um.. still waiting for pics to upload.

Cheers,
Rob.

To how to stop the pipe spinning, first the pipe is a push on fit. First time I forgot to anchor it and it wandered into the belt, It didnt really slip much though so all I did at one end was drill a hole and put a countersunk screw in at one end. As I made the centre larger than the pipe then used the drum like a lathe and used craftwood for the drum it worked out well balanced, I did though polish the PVC pipe as it was a bit thicker at one spot. As to colour of socks, now thats a silly question, what else could they be but True Blue, and held up with fence wire. Rob

Hi

In the school where I worked, they had a 900mm drum sander. This had Two drums with different grades of sandpaper the drums were aluminum approximately 150mm in diameter. The sandpaper was 150#mm wide.

Why stop at a 25mm shaft? Why not use a tube as the shaft in the drum and have a (25#mm) shaft running through that or possibly weld in "stub" shafts.This will keep down some of the weight and make the drum more rigid. I imagine in doing it this way you would need far fewer "disks".

Um.. ya lost me.

The discs when attached together make the drum.
Using less reduces the width of the drum.
I'm not seeing what you are seeing... I think.

Using a pipe for the shaft I understand and it would possibly be lighter than a solid shaft but I think it would need to be pretty thick walled for the span.

My concern with either a solid shaft or pipe is it sagging in the middle and being like a kangaroo bicycle when it is spinning.

I assume the discs when all glued together to form a drum prevent this sagging or flexing from happening. As long as the shaft is a snug fit through the centre of each disc.

Cheers,
Rob.

Yes you are correct, How I built it was the disks were drilled to be a tight fit, then I glued one side and built up the drum that way, the excess glue helping to hold the disk to the shaft as well as the pulley. Your disks have to be a bit big because the holes you drill for the shaft can be a bit out so you need to lathe the drum after completion. I did think of a pipe as a shaft as per a truck drive shaft but discounted that because I believe its more complex to build. Weight is not really an issue. My one will be about 50lbs, only issue I have is the belt squeals on startup.

Just a thought, maybe you should have two drums, seeming as you making your own, one after the other, the first rough sandpaper and the second fine sandpaper, just a thought...

Originally Posted by mickelmaster

Just a thought, maybe you should have two drums, seeming as you making your own, one after the other, the first rough sandpaper and the second fine sandpaper, just a thought...

"just a thought"

That's exactly why I asked, coz I was sick of seeing this damn thing in my dreams.

Originally labored over the though of building an open end thing like the jet sander coz I want to be able to sand wide items.
After CAD drawing etc, etc realised I may as well either part with the $$ and just buy one or build a new shed for my Frankenstein creation to go in.

The new design of 1200 wide can be built pretty narrow from front to back with fold up material beds... I'm hoping. So the real cost of space will be its width only... fingers xd.

I'm still in two minds with the whole changing from one drum to another.
I'm hoping the changing of grit is pretty quick and easy with the shop notes design.

... if any one out there has built a shop notes drum sander I would like to know their thoughts of the paper fastening system.

Changing drums with belts and shafts and spanners and bolts and all them thingies.
Sounds like more effort than it needs to be, especially as I am planning to have the drum hanging rather than sitting.
1200 wide at @ 25 kg could require some real patience, care, eye for detail... then we start venturing into uncharted waters.

As a wise man once said, " if ya can't fix it with a hamma..."

Also, I reckon if I manage to pull off 1 good drum in the project, I'm doing well.

Cheers for the replies.
Rob.

A whacking big drum sander as far as I am concerned gets the wood flat and reasonably well sanded, its then easy with a finishing sander to polish to the desired finish with a fine grit in a couple of passes. Remember the grit on a drum sander travelling at speed can be quite course and still give a near done finish. I was into these thought before I built it, after that, no its a coarse grit machine.

Hi there,

These beasties are common amongst luthiers. Try asking Tim Spittle at Australian Tonewoods, his is home made and not 1200 wide but Ive seen it in operation and it works well. http://www.australiantonewoods.com/atw/index.htm Im not sure if its the shop notes design.

There was also a thread on the ANZLF about this topic some time ago but I cant find it at the moment. i'll have a look when I have more time.

One point I forgot to mention, these machines tend to create a snipe at the start and finish of the work so when dressing the wood its best to allow extra length for a cut off later. On my benchtop end the snipe looks [ike an intentional feature.

Originally Posted by rrobor

One point I forgot to mention, these machines tend to create a snipe at the start and finish of the work so when dressing the wood its best to allow extra length for a cut off later. On my benchtop end the snipe looks [ike an intentional feature.

Yeah, I'm good at ending up with "intentional features"

I was thinking with my double feed rollers, I might reduce the snipe effect.

Originally Posted by Weekend hack

"I'm still in two minds with the whole changing from one drum to another.
I'm hoping the changing of grit is pretty quick and easy with the shop notes design.

... if any one out there has built a shop notes drum sander I would like to know their thoughts of the paper fastening system.

Changing drums with belts and shafts and spanners and bolts and all them thingies.
Sounds like more effort than it needs to be, especially as I am planning to have the drum hanging rather than sitting.
Rob.

I have built the shop notes version and unless you have two drums, two sets of pillow blocks or what ever sort of bearing you use, it would be way more trouble than its worth.

Mine has the belt held in place as per the Shop Notes design and it works perfectly. Once you get the hang of applying it to the drum its a matter of a minute or two to actually fit the length of paper.

One word of caution though, I flattened the thread on the arbour of my saw somehow, I suspect because the pulley got a little loose on the arbour. I am in the process of replacing the arbour and will adapt my sander to be powered by a motor from a GMC dust extractor assuming I can work out the logisitics.

Ray