Truing up a sanding disc?

[skou]

Me too! I think a hook/loop disc would vary more than 5-10 thousands.

JPG, you're right. When I had my first ER, back in the '80s, I ordered a hook-n-loop disc set. Disc changes were really fast. Finish edges were really nice feeling.

HOWEVER!

those nice-feeling edges were NOT sharp and square. The velcro has some give to it, and would round over the very edge of a joint, where the hooks and loops were compressed as the disc spun. Aluminum (my Model 10 stuff) or steel (your Mark-X stuff) won't compress, and will leave a sharp corner.

With the Model 10, I have the ability to offset the ripfence. Up to 10 degrees or so. By feeding in a workpiece backwards, so the front half (the falling half) of the disc is touching the workpiece, a pretty good joint is doable. Not so with the velcro rig.

But, if I had the need to make some wooden toys for my extended family, and wanted to smooth the sharp corners, velcro pads would be the way to go. (Which is why I bought a 15 dollar Skil brand {rebuilt} 5 inch 8 hole random orbital sander.) That thing also works great smoothing out new Lodge cookware, but the filter won't fit inside a 12 inch skillet. So, the dust gets blown in my face.

steve

[BuckeyeDennis]

Funny you should mention that, Alan. (Sorry, I'm listening to "It's 5 o:clock somewhere.") I just happen to have all the pieces!

However, if doing it this way, wouldn't I want the headstocks on different axes? (That is the plural of axis, not a big hatchet.) that would male more of a random sand on the sanded disc?

Oh, and doing it this way, I don't need to order a tailstock arbor.

Dennis, THANKS!!

steve

Agreed, an axial offset between the discs would give better results. But at the time, I didn't see an easy way to do that and still maintain angular alignment between the headstocks.

But now that you mention it, I suppose that you could mount the second headstock on only one of the way tubes, giving you angular alignment with a good axial offset. Then rig up some sort of anti-rotation link to the otherwise empty headstock bore.

[skou]

The easy way is to just pick up another SS that has a disc with it.

THANKS for the "good" idea!

I just found a decent looking ER, on a wooden base, for $150. Has the disc, and looks to be in good shape. It also has the rare B SPT adapter. (SCORE!!)

Seriously, I've got an addiction here. Can't pass up a good deal.

(And, I was only joking Pieceseeker.):D

steve

[keakap]

"A 64th is only .0156, if you need or want your wood working that close you bett..."

make a wood cylinder (barrel) ~14" D, 20 'staves', 24" length; should be doable on a woodworking machine of any worth, THAT is accurate enough. But make the edge cuts off just one 64th of an inch- that's 40 edges times that 'only .0156' and you have a total error of 5/8.
Anyone want to guess how well that bugger will hold water?

I dunno; if it will or CAN do it, why not expect the machine to do it? Sometimes, anaway.

[keakap]

I've got an aluminum (ER) disc that is not quite flat. Is there an easy way to true it up? ...

I've got some PSA 2 inch rolls of sandpaper, in 60, 80 and 120. I've also got 3, 11 inch aluminum sanding blocks ( Great Planes brand) that are made to hold this paper. steve

I once got fed up with the sanding marks on a workpiece due to the sanding disk being wobbly (having observed that the only working surface of the 12" diameter disc was about 1/2" at the 'high spot' very much like the Conical Disc, so it was akin to using a jointer knife that had one nick in it). The fix was as you suggested.
Cleaned the offensive disc to the N'th. Mounted it, with the table slid up to within 1/8", and sanded it flat, very slowly and gradually, using somethng with 120 sandpaper on it attached to the miter gauge. Used a combination of arbor positioning and miter gauge sliding to get whole disc done.
And it didn't take much since only the bad area came off.

Funny, I do remember thinking it wasn't going to work, so I wasn't particularly careful (other than slow), and later thought that might be why it worked so well and quickly.

Now I occasionally use that disc for alignment checks and such.