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Edited 1 time(s). Last edit at 09/20/2016 04:29PM by John E Powell.

Idea 1:
A belt sander, a sliding table held at an appropriate angle to the bed of the belt sander, a disk to hold he foam and allow it to rotate. Advance the table until the foam touches. Rotate the disk.

Chris Richer
Iroquois ON

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Edited 1 time(s). Last edit at 09/20/2016 04:28PM by John E Powell.

Mount the foam disk on a threaded mandrel, backed by nut and washer. The washer needs to be the same diameter at the disk, if you can work with that. Put a smaller washer on the front and snug up with a nut. Mount the mandrel in the lathe and hold a sanding block against the outside face of the disk at the appropriate angle and distance. Sand until you have the thickness you desire.

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John,
I believe that I may have the solution.
Use a lathe.

First create a back plate so that it is exactly the same diameter as the foam disks with a backing rod in the center.

Basically, it would be easy to do this with a piece of wood, nylon or similar material. Use a drill press to drill a pilot hole through the pice of material that you use for the backing plate. Use a flat topped bolt and run the bolt through a countersunk hole in the center of the disk.

Place the disk in the head stock chuck and use grinders, sanders or shaping tools to insure that you have a perfectly flat surface. This one will be the same diameter as your EVA disks.

Then, make a 2nd one that is about a 1/4 inch or a 1/2 inch smaller than first disk. The idea is that you place the eva disk against the first disk in the head stock. Then, have the 2nd smaller disk in the chuck of a live head stock for your lathe.

Place the piece of foam on the first disk and then bring the 2nd disk up tight to the foam and tighten the tail stock. Tighten the tail stock to clamp the foam securely between the two disks.

Turn on the lathe to high speed and use a piece of solid backed sandpaper to feather down the edges of the foam. This of course would mean that all of the feathering would be done on one side of the foam only.

Then, for the next pieces, just loosen the tail stock clamp, insert the next piece, tighten the tail stock and carry on. Likely you could do this at a rate of 10-15 seconds per piece of foam.

In the past, I have used such forms and clamps to shape butt caps without leaving any marks on the butt cap itself. It is simple and it works well.



A simple way to do this would be to use a 2 inch faceplate for your lathe like this one.

[www.pennstateind.com]

Just use a piece of nylon and use screws through the face plate to attach the nylon to the faceplate.
Then, turn on the lathe, and trim the nylon to the finished 2 inch diameter that you need. Do, a final finish pass across the face of the nylon, and you will have your head stock face clamping surface.

This live tail stock could be used for the clamp, if you made a piece that was a bit larger than the 1 inch diameter of the end pice of the tail stock.
[www.pennstateind.com]

If a hole in the center of the disk is not a possibility, then clamp the foam between two surfaces. the upper surface would contain a hole smaller than the outside of a bearing and the then apply clamping pressure to the inside of the bearing. This will allow rotation, with out the hole.

Chris Richer
Iroquois ON

What Roger outlined above is essentially the same thing I had said in the post above his. It should be a simple means for achieving what you're after.

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Tom,
Sorry for double posting. You are right.

However, I have used that technique often to do some shaping of something that needs to have no holes in it.

Be safe

You might want to try making a flush backing plate as outlined
above but use adhesive backed male velcro on the plate. The foam should
act as female velcro and provide fast on and off - similar to a sanding
disk...

Two sided tape.

Curt