Author Topic: Drum/ Thickness Sander  (Read 35387 times)

Offline Fergus OMore

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Re: Drum/ Thickness Sander
« Reply #25 on: January 17, 2015, 06:57:23 AM »
When all is said and done, the abrasive belts are required. They have to be costed, obtained and glued.

Not cheap.  :bang:

Regards

Norman

Offline Manxmodder

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Re: Drum/ Thickness Sander
« Reply #26 on: January 17, 2015, 11:19:11 AM »
Hi Simon, this is an interesting project you've started and I'll be watching how it develops as you progress.

I just did a bit of googling for info and found this link to various drum sanders. The Jet sander seems to use a conveyer belt system similar to your design and if you look at the specs you can gather some useful info about drum size and feeds etc......Link: http://www.rockler.com/jet-benchtop-sander-1hp

.....OZ.
Helixes aren't always downward spirals,sometimes they're screwed up

Offline Fergus OMore

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Re: Drum/ Thickness Sander
« Reply #27 on: January 17, 2015, 11:56:08 AM »
And the provision to 'crown' the rollers to keep the belt 'on track'?

Let's say that I am farting about with my bandsaw- and trying to replace a broken twin clarinet stand for my wife's A and Bflat clarinets.

Said I'd been there :poke:


Norman

Offline S. Heslop

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Re: Drum/ Thickness Sander
« Reply #28 on: January 21, 2015, 12:57:30 PM »


I've been a little apprehensive about the idea but gave it a go today. I'd done some tests on spare disks of MDF and didn't have any luck getting the diluted glue to penetrate to any depth, even trying to add a bit of vacuum with a vacuum cleaner. It might be a case of just getting it fairly close to final dimension and soaking it for a while to get just the surface hard. I'm still also unsure how the MDF will react to being soaked in water, as it'll probably take months to dry out fully (especially if the glue seals it), so the whole thing might warp after a while.

But with no other options i'm aware of, im still trying it. If it doesn't work out i'll just replace the MDF with plywood like I mentioned earlier.

Offline NormanV

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Re: Drum/ Thickness Sander
« Reply #29 on: January 21, 2015, 01:30:05 PM »
The trouble with PVA is that it dries rubbery and will clog up the abrasive paper that you use to smooth the roller. Varnish would do a better job of hardening the MDF roller in preparation for sanding.

Offline Fergus OMore

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Re: Drum/ Thickness Sander
« Reply #30 on: January 21, 2015, 01:37:57 PM »
Simon

If there is no metal insert and you have pva still wet, why not microwave it? After all, it is a way to season timber.

Regards

Norman

Offline S. Heslop

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Re: Drum/ Thickness Sander
« Reply #31 on: January 21, 2015, 02:12:55 PM »
The trouble with PVA is that it dries rubbery and will clog up the abrasive paper that you use to smooth the roller. Varnish would do a better job of hardening the MDF roller in preparation for sanding.

I did consider varnish, but I preferred the idea of splashing about PVA glue to anything solvent based.

I've been thinking about tool geometries a bit. In past experience, turning wood freehand with anything that has a fairly positive rake is a recipe for disaster, but it might have more success in cutting the MDF if I can keep it under control. The way it's set up at the moment, there should be alot of support to prevent the tool from digging in. The other option might be using some sort of router sled to route the thing round as it spins.

I think i've got too much time to think while waiting for this stuff. I'm also too scared about knocking the thing over and spilling it everywhere if I try get on with something else in the meantime.

If there is no metal insert and you have pva still wet, why not microwave it? After all, it is a way to season timber.

Unfortunately there is a metal insert, but that's an idea i'll probably keep in mind for the future.

Offline RussellT

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Re: Drum/ Thickness Sander
« Reply #32 on: January 21, 2015, 05:17:32 PM »
It sounds a lot of trouble.

I'd try sleeving it with PVC pipe or looking for a roller out of an old printer or typewriter.

You could also try polyester resin (fibreglass stuff) or car body filler to stabilise the surface.  It doesn't take long to set although a bit of extra hardener does no harm in the current weather.

Russell

Offline S. Heslop

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Re: Drum/ Thickness Sander
« Reply #33 on: January 21, 2015, 06:20:44 PM »
You could also try polyester resin (fibreglass stuff) or car body filler to stabilise the surface.  It doesn't take long to set although a bit of extra hardener does no harm in the current weather.

That's a good idea.

I did think about sleeving it with PVC pipe but I couldn't find any in the dimensions required, which was a shame.

Offline SwarfnStuff

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Re: Drum/ Thickness Sander
« Reply #34 on: January 22, 2015, 12:35:23 AM »
"I did consider varnish, but I preferred the idea of splashing about PVA glue to anything solvent based."  Probably too late, but there is water based floor varnish that just may do the job. The solvent base I guess is good old fashioned water and it dries hard enough for floor treatment.
Good job so farm
John B
Converting good metal into swarf sometimes ending up with something useful. ;-)

Offline Fergus OMore

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Re: Drum/ Thickness Sander
« Reply #35 on: January 22, 2015, 03:46:36 AM »
.

I did think about sleeving it with PVC pipe but I couldn't find any in the dimensions required, which was a shame.

Oversize plastic gutter pipe can be cut and heat sealed with a soldering iron.

I'm thinking about a use for scrap plastic. Got a broken garden table to re-cycle :bang:

Norman

Offline S. Heslop

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Re: Drum/ Thickness Sander
« Reply #36 on: January 23, 2015, 05:50:11 AM »


All this waiting is killing me. I dried one of them out on a radiator and it cracked a bit, which I was actually happy to see since it was evidence it was actually drying and that a good amount of the stuff managed to soak in. It'd probably be prudent to let it stabilize for a while in the garage though, but i'm not sure how much longer I can stomach waiting.

Offline S. Heslop

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Re: Drum/ Thickness Sander
« Reply #37 on: January 23, 2015, 07:37:55 AM »
Well that's too bad, it didn't work. Nor did different tool geometries.

I guess my options are to find a piece of PVC pipe and see how easily that turns (I doubt it'd turn too easily), use a piece of PVC pipe and mould some sort of body filler/ epoxy thing (I also can't imagine body filler turning too pleasantly without chunks of it chipping out), or I could scrap the MDF and try again with plywood.

I think I might just go for plywood. I'm not so hot on the idea of using this MDF any more since, after being wetted and dried on a radiator, it probably won't stay the same shape unless I leave it for a month to stabilize. Plus I have the plywood on hand.

That said, there's probably a likelihood that i'll experience some chipping with the plywood too, what with turning it on the end grain. Although Matthias Wandel had success turning plywood for bandsaw wheels.

Offline Manxmodder

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Re: Drum/ Thickness Sander
« Reply #38 on: January 23, 2015, 03:06:12 PM »
The success of plywood will very much depend on the type and quality.

Birch ply would probably be a good bet,but it is not cheap. I would give serious consideration to the making a glued up roller blank from staves with grain longitudinaly as VT Steam has previously mentioned.....OZ.
Helixes aren't always downward spirals,sometimes they're screwed up

Offline vtsteam

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Re: Drum/ Thickness Sander
« Reply #39 on: January 23, 2015, 04:19:04 PM »
Just rip strips with the blade set to 45 degrees. Use real wood. BYU.
I love it when a Plan B comes together!
Steve
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Offline S. Heslop

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Re: Drum/ Thickness Sander
« Reply #40 on: January 26, 2015, 11:15:59 AM »
Let there be squares.





Had a bit of an accident trying to grind a tool to not tear out the wood as much.



Eventually got it round with only a few chipouts. These could be filled but i'm not sure if it'd affect things too much.

Now i've got to make the second roller, which i'll probably cut the corners off the squares before gluing it up so there's less to remove in turning.

Offline micktoon

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Re: Drum/ Thickness Sander
« Reply #41 on: January 26, 2015, 04:07:39 PM »
Hi Simon , looks like the plywood must have been quite decent stuff , the worse quality stuff seems to have so many voids in it these days I doubt of you could have turned it like that. It looks like it has turned out not bad at all so hopefully will do the job for you.
 I had been going to say for the car body filler idea , I think better then turning it would have been to have a sander passing back and forward as the cylinder you were working on rotated, this might still be an idea to finish off and crown the plywood version, I am thinking a hand held electric half sheet type flat base sander ?

 Good work .
  Cheers Mick.

Offline S. Heslop

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Re: Drum/ Thickness Sander
« Reply #42 on: January 26, 2015, 05:04:04 PM »
I did sand it a bit, and tried sand it more at the edges than the middle to maybe give it a bit of a crown. But it didn't produce anything measurable and I thought i'd try leaving the crown for now and seeing how it tracks on its own. The portable belt sander I have doesn't seem to have any crown at all, but does have a flange that keeps the belt from slipping off.

Yeah i'm really surprised by the quality of the plywood too. There's a few ugly bits where the edges of plies meet and overlap. Of all the squares I cut I only had to reject 3 for voids/ layers coming loose. It wasn't expensive plywood too, just WBP from Doves in Newburn.

Also I just glued up the next roller. When trying to shake glue out the bottle I managed to get it all over my Fanciest Shirt. Hopefully it washes of or i'll have no shirts left without holes or glue on them.

Offline S. Heslop

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Re: Drum/ Thickness Sander
« Reply #43 on: January 28, 2015, 06:41:46 PM »
Finished the second roller. Now i'm just waiting on the belt and some bearings to get delivered.

Something i've left late to really consider is the motor i'm gonna use. There's a second hand shop nearby with a whole shelf full of motors that look perfect for the job, but the guy is unfortunately refusing to sell them individually since they come as a set for a jacuzzi. If I had the money i'd probably buy the lot.

A while back a guy going by malbenbut gave me a motor for free. I'd been saving it for a bandsaw i'm hoping to build after this sander is complete, but if I can't find a more suitable motor before then I'll just use it with this.



Another reason i've been avoiding using it is because it's so big I figured it wouldn't fit, but I decided to measure it up anyways and it just barely fits...



Of course I could always move stuff around to accommodate it better since I haven't started building the body yet. But i'd rather at least avoid making the thing any taller.

Offline greenie

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Re: Drum/ Thickness Sander
« Reply #44 on: January 28, 2015, 09:47:16 PM »
Have you worked out what the "surface speed" for the sanding roller will be, too slow and it will take forever to remove anything, then if it's too fast it will burn the finish on the timber ?

Offline S. Heslop

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Re: Drum/ Thickness Sander
« Reply #45 on: January 29, 2015, 09:30:07 AM »
Haven't worked out any surface speed, but i've found commercial sanders quoted at running 1400rpm with the same sized drum as i'm going for.

Offline S. Heslop

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Re: Drum/ Thickness Sander
« Reply #46 on: January 30, 2015, 10:19:49 AM »


The stuff arrived today, surprisingly early. I got the belt cut, terribly though. I feel a bit silly because it's only about 10mm wider than the table, and I should've built the table to match the belt.  But I was planning on using some 'real' conveyor belt material at first, but couldn't find any for sale or any information on how to splice it (other than product pitches).

Anyways, as predicted, there's problems with it tracking. I spent a while tweaking it without any luck. With so much to adjust I'm not really too concerned about it tracking in both forwards and reverse though.

I suppose i'll try crowning the drive roller more heavily to begin with.

In all honesty I was sort of hoping to have a lazy day today, but the stuff arriving has made me feel like I need to do at least some work on it.

Online DMIOM

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Re: Drum/ Thickness Sander
« Reply #47 on: January 30, 2015, 10:40:56 AM »
It might be worth considering lining the two vertical sides where the edge of the belt will touch/drag with Formica or similar?

Offline Fergus OMore

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Re: Drum/ Thickness Sander
« Reply #48 on: January 30, 2015, 11:01:08 AM »
Simon
             Probably your supplier at a reasonably  approachable price is Wickes. I bought a long roll- about 12 metres long but only 10cm wide. It's about 12 a roll. How to join it is any bodies guess. All that I can tell you is that I bought stuff for an old Picador but it was only about 3" wide. The firm was Davis Abrasives then in Byker and is now in Cramlington. The joints were diagonally cut and scarfed and glued.

Maybe this helps. Let me know

Norman

Offline S. Heslop

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Re: Drum/ Thickness Sander
« Reply #49 on: January 30, 2015, 11:56:32 AM »
It might be worth considering lining the two vertical sides where the edge of the belt will touch/drag with Formica or similar?

Yeah I was considering something like that if I couldn't get the belt to track at all. The cutouts to let the drum reach the table though would be a problem since the belt looks like its trying to ride up over there, since the seam on the straight side isn't perfectly lined up.