Thread: home made drum sander

I've been watching this thread, hoping someone would cover the one thing that has prevented me from building my own...

How do you plan to attach the paper?

For me, gluing is not an option. I've thought about slotting each end of the drum for the paper to "tuck into" after being spiral wound, with some form of cam assembly to lock the paper ends in place, but I haven't managed to come up with anything within my meagre build abilities.

The best I've come up with is a pocket screw angled in from each side of the drum, but then you need clearance to get a screwdriver onto the screw for adjustment.

Anyone have any thoughts?

Originally Posted by Skew ChiDAMN!!

I've been watching this thread, hoping someone would cover the one thing that has prevented me from building my own...

How do you plan to attach the paper?

For me, gluing is not an option. I've thought about slotting each end of the drum for the paper to "tuck into" after being spiral wound, with some form of cam assembly to lock the paper ends in place, but I haven't managed to come up with anything within my meagre build abilities.

The best I've come up with is a pocket screw angled in from each side of the drum, but then you need clearance to get a screwdriver onto the screw for adjustment.

Anyone have any thoughts?

Check out the dodgy pics I posted in an earlier part of the thread.
There is a pic (hand drawn) of the end disc of the drum.
The disc has a segment in it and the segment is fixed with a screw through it.
The screw threads into a thread insert fixed into the body part of the disc.
The drum would have one of these end disc's at each end.
The paper is wound around the drum and fixed / sandwiched under the segment.
The segment would need to sit under the profile of the drum once the paper is fixed in to prevent a knocking as the drum rotates.

At least this is how I understand the shop notes type of drum.

Cheers,
Rob.

Ahhh... gotcha.

I had a quick peek at those pix, but was looking at the one above the caption and was wondering "?" Somehow I missed the right one.

Mmm... I'm still not sure on that one. As you say, it has the potential to cause serious scratching if not snugged up tight. I think I'll keep looking for alternatives. (Not that I'll be holding my breath! )

Dont know why you dont want glue. If you use a plastic type drum getting old glue off is easy, also you only need to tack on the ends. I thought of routing out a half moon chanel and screwing in a piece of half dowel over the paper but the disadvantage of that is to balance. One grove must be exactly 90 deg from the grove at the other end and this may or may not work out as you wrap your 4" paper on the diagonal. I bought my paper on Ebay. 8" wide 50m for $50, sliced that in half to save waste and it works a dream. Glue I use is weldbond and the reason is purely set time, Aquadere takes too long.

Originally Posted by rrobor

Dont know why you dont want glue. If you use a plastic type drum getting old glue off is easy, also you only need to tack on the ends. I thought of routing out a half moon chanel and screwing in a piece of half dowel over the paper but the disadvantage of that is to balance. One grove must be exactly 90 deg from the grove at the other end and this may or may not work out as you wrap your 4" paper on the diagonal. I bought my paper on Ebay. 8" wide 50m for $50, sliced that in half to save waste and it works a dream. Glue I use is weldbond and the reason is purely set time, Aquadere takes too long.

Maybe I'd be sold with a pic or 2.

I don't really understand how changing the drum could be "simple"

I guess another alternative would be along the lines of the sleeveless drum sanding drums.
I think they use a similar fixing as you have described with the pin holding the paper in place.

Don't really know, but I think I will try the shop note style when I finally get roundtuit.

Where you make your mistake is in the belief that you can take your workpiece of this rather large machine and have a perfect finish, this is not the function of a large roller sander. Its function is if you have say a table top of 10 or so boards, it will not be flat, some are down, some on a slight angle etc. Put that through the sander and you can see the valleys so you sand till they are gone. Now my roller pulley to motor pully will be about a reduction of 5 so the drum is rotating at a few hundred RPM using 80 grit and the finish only needs a couple of passes with a finishing sander to have a U bute. So the simple answer to how do you replace the drum, it doesnt apply, I planned for it but I was wrong. My sander by the way is in storage, she is a bulky bitch so the roller and motor are off and the frame is used as a table

The reason I don't want to glue the paper is because the machine I want to build is a compromise.

I'd like to be able to sand 900mm width (ie. benchtops) but also be able to use it for bringing BS cut veneers down to final thickness. I'm not stupid enough to try feeding <5mm through a thicknesser. (Well... not to try again, anyway. )

This raises two points:

Firstly, I'm not confident in my abilities to build a drum that'll span over 900mm but won't have some deflection in the middle under load. That'd be fine for a benchtop but not for veneers.

So, my solution is to break up the drum into two shorter lengths (say 500mm) and put a pillow block in the middle. This'll mean the benchtops would need two passes through for each change in height, but I can live with that.

Secondly, I'll need to be able to change grits fairly simply to switch between the two uses. I guess that one drum could be glued, but the other...?


Perhaps I'm being unreasonable in my expectations. I don't think so, but I guess I'll find out one way or t'other once I actually pull my finger out. (I've been giving thought to this for several years now... )

Ok how about driving your unit at the centre, you could then use PVC pipe as a sheath on your drum and a simple pin type lock on the pipe to hold it. It would mean you would have to take the end bearing off to change rollers but that would only take 10 mins or so. For your job I do get a slight flutter in the wood rather like off an electric plane or thicknesser, I put that down to being fractionally out of balance. but it is not worse in the middle. If I was after perfection I would get an old truck driveshaft and get ends milled and cut for bearings then build the thing up with craftwood disks to the desired roller, bearing in the middle, na bit too hard.

Originally Posted by Skew ChiDAMN!!

So, my solution is to break up the drum into two shorter lengths (say 500mm) and put a pillow block in the middle.

Why not have two separate drums offset and overlapping? ie. two 600mm
drums with a 100mm overlap. One behind the other? Or is that too much engineering?

Originally Posted by mkb

Why not have two separate drums offset and overlapping? ie. two 600mm drums with a 100mm overlap. One behind the other? Or is that too much engineering?

The answer is in your question. (I used to hate it when my lecturer used to tell me that. )

I'm only a lowly woodworker, metal's most definitely not my thing. So simplicity will - hopefully - be my key to success.

FWIW, I'm planning mine to bolt onto my lathe bed, so I can direct couple the chuck to the end of the drum. The lathe is variable speed so I can drop the beast down to a suitaly low RPM without needing to worry about pulley sizes or belts.

If I was doing it again and wanted the perfect machine it would be one long drum. the centre of which would be a truck drive shaft which is steel pipe. That would be cut to length and milled and a dics and stub axil welded in each end (rather like a large thumb tacks) then when everything was spot on and balanced Id fit craftwood rings to bulk up the drum and finish it with PVC pipe. I dont get centre issues in my drum, what I do get which I think is my fault , a slight flutter due to being slightly out of balance, I made some of the rings out of chip board and got a bit ofrip out when lathing it round.

Go and have another look at this thread, OK, the drum is only 100mm wide, but by using a metal shaft, you could go to 1.5mts long shaft with NO deflection in the middle at all.

https://www.woodworkforums.com/f44/thickness-sander-97109

For the drum, instead of a hunk of steel, you just use slabs of chipboard glued onto the shaft, then get them turned to size.
For the paper, use this type of product, just roll it around the drum, to hold it down tight, either screw the ends down with small blocks of wood holding it, or glue the ends. Lots of different grits and widths of this stuff readily available, no need to be brand specific, it all works.

http://flexovitabrasives.com/index.h...ce189d1169fc0d

For the rise and fall table, make sure you can adjust it up and down on each side, so you can make the table dead true to the sanding drum.
A thin sheet of glass is about the best thing to add to the table top, as this eliminates any drag on the timber, from whatever material you use on the rise and fall table top.
The only drag you get, is pressure from the sanding drum pushing the material back at you.

regards radish

Sorry but what we are trying to do is sand benchtops and tabletops. I have a 2 horse motor geared down about 4 times and after an hour or so working I give it a rest. Sandpaper is rolled on in the diagional and is 4ins wide. I use wheels under the tabletop for ease of rolling it through and the table I have under the roller is a full sheet of yellow tongue. Trying to have some form of sheet going round the drum and being attached would not work as the balance would be too tough and glueing the paper in that way it needs to be a tight butt joint or it will bounce on the joint and destroy the paper and/or the workpeice.