Official Luthiers Forum!

I've noticed that many different binding jigs seem all to have the exact same white plastic donut as the bearing surface/offset from the base. It can't be coincidence that everybody is custom milling some UHMW plastic to near identical dimensions. Is this a commercially available part being repurposed from something? Anyone know how one would get a donut like this without having turn it on a lathe?

Thanks!

Don't quote me but I thought John Hall mentioned here a few years ago that he sold them, though I don't see them on his site. Maybe drop him an email or call. http://www.bluescreekguitars.com/

I got one from a friend. I think he might have gotten it from John Hall. ...before getting that one, I cut out a piece from a cutting board we were throwing out. I drilled a hole through it attached a screw with a nut, put it on my drill press and with a lathe tool shaped it into a donut. I worked fine...

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Steve Sollod (pronounced sorta like "Solid")
www.swiftcreekguitars.com

I did the same as Steve. Worked well.

Alex

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"Indecision is the key to flexibility" .... Bumper sticker

I bought mine from John Hall last year. Had to drill mounting holes to fit my Rigid mini router. Works like a charm!!!
I think I paid twenty bucks plus shipping.


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I did the same and works great. Bob

What if you don't have a lathe tool

I solved the problem with some door hardware. But this thread interests me because I think the plastic donuts are probably better though this works well enough for now.

If John intends to carry them again, I won't step on his business - but I have access to a CNC lathe and if making a small batch of them would be useful I'm happy to look into it.

I turned mine on my wood lathe. That UHMW type material turns pretty easily.

Here's an old thread.

viewtopic.php?f=10101&t=40575&hilit=donut

Kevin Looker

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I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

I made one once by screwing a flat disc to a block of wood and rotating it at an angle against my stationary disk sander.

That sounds like a good idea and doable for me since I have those machines.

So... What is the proper shape? I image a very short flat spot right around the bit would be a good idea?

I think most have a flat about 1/4" wide. The one below is from high quality Masonite (oxymoron?) and has a 5/16" flat.
A little wax lets it slide like UHMW plastic. One potential benefit of Masonite is it can be glued down instead of needing screws.
diameter and taper just need to provide enough room to set on the body a comfortable distance away from a spinning bit.

In the spirit of DIY donuts, I made the one on my binding jig from a cube cut from a scrap piece of fir 4x4. I clamped a pivot post to the fence on my band saw in line with the leading edge of the blade and positioned the fence so that the distance from the pivot to the blade was 6 inches. I then cut the 4x4 block by sweeping it (with an appropriate sized spacer block between it and the pivot) in an arc through the blade. I then rolled the block 90 degrees and swept it through the blade again. That produced a surface with two 6" radii at 90 degrees to each other on the one face. I made it into a smoothly curved 6" radius dome all the way around on the belt sander, cut the dome off the block, drilled a hole on the drill press, and double stick taped it to the carrier plate on the binding jig.

I arrived at the 6" radius using the thickness I wanted for the donut and its width in the sagitta of an arc equation and solving for the radius. It works just fine on the jig.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

I used my Wells/Karol jig to cut it out of acetal (delrin).

http://www.ebay.com/itm/UHMW-Plastic-Ro ... xywXFSbpCf

Mike Franks