Woodworkers - which sanding drum?

[mental4astro (Alexander)]

Hi all,

I'm looking for a sanding drum to carry out some timber shaping. What I want from the drum is to give me a square/parallel result.

I've come across two types. One is the solid rubber arbor using a sleeve, the other is the quick change drum that uses standard sandpaper.

Which would give me the better result? Any other alternatives?

Cheers,

Mental.

[Kunama]

What are you making Alex? I don't like using a round drum to try make straight, square and parallel products unless you have a jig to mount the tool (either drill or sander/grinder) and a guide rail to slide the timber against. That is the only way to really get straight and parallel pieces with drum kits.

A cheap Ozito belt sander from Bunnings would be a better bet.

[mental4astro (Alexander)]

I have a jig to mount a drill in to do the job with, no problem there. It's to make equal curved cuts in a rocket box for the alt bearing of a dob mount - the Teflon pads will sit in this cut so it needs to be accurate. This is not a job to just eyeball & wing freehand. A jigsaw won't do as the blade can sque while the curve is cut. A jigsaw can do the gross cut, but I only see a sanding drum being able to do the fine shaping. A hole saw won't do either.

[LewisM]

A BIG hole saw would do it

JIG it, and a drum sander should be fine.

[Babylon5 (Shane)]

I have a Shopbot CNC that can do precision cutting that might be able to solve your issue.

Regards,
Shane.

[mental4astro (Alexander)]

You are a lucky man, Shane. Shame we're some 700km apart.

No, a hole saw won't do. The cost of such a large saw is not a good investment. It wouldn't give me the size I actually require. A sanding drum would be more practical & can be used to trim different sizes.

Still, the question remains, is there a difference between the quick change and the sleeve drums?

[Babylon5 (Shane)]

I've used both types and the sleeveless has a bit more give due to the different material it uses. What you really need is something that attaches to both ends to alleviate the flexing that can occur when sanding.

Even though I'm 700km away I can still cut it for you, I'll do it for free if you just pick up the postage.

Shane.

[ZeroID (Brent)]

Router ? Set up the two sides as a platform with a central pivot arm ?
To be honest I gave up with trying to make accurate arcs, I just cut a 'V' and the bearing sits in it with the friction material at the two contact points.

[peterl]

Alexander.
How about one of these.
available from Hare and Forbes. Cost $200.00
available with different size drums and abrasive refills.
As Brent just posted you could mount a router or this on a stand with your work pivotting and have very accurate curves.
I used this method on the bearing curves when I made my 20 inch obsession clone and works well.
Just a suggestion, and you can use this for lots of other jobs later as well.

[GraemeT (Graeme)]

Alex, Are you cutting a concave curve or a convex curve? I was able to get VERY accurate convex runners for my EQ platform by bolting a pivot arm at the required radius above my belt sander and bolting the runners on an A frame, so that they swung over the belt. This gave a perfectly circular result. The same idea could be used with a convex cut with a drum sander with a radius smaller than that of the cut, but as big as you can get. You would need a solid rubber drum rather than a foam backing and a rigid mount for both the pivot and the drum.
Cheers.

[mental4astro (Alexander)]

Graeme & Brent, you reminded me of the little jig I made for my router. I made two, a larger one for large radii, and a smaller one. I'll chase it down and see if I can go as tight as I need.

All the same, I checked the Carbatec site and they have both, thanks for reminding me Peter. I'll drop by and check them out. One of my most favourite stores in the whole world, like Hare and Forbes.

[Babylon5 (Shane)]

If you do end up buying a spindle sander and want to know a method to create your own sanding sleeves for a lot cheaper than what it costs to buy them from Carbatec etc, just send me a PM.

Shane.