Official Luthiers Forum!

I searched the OLF and lifted a whole bunch of ideas from the other jigs OLFers have built. Rod True was the most generous "donor". Sure works well.

So now mine is up for grabs for ideas too.



I put up a little tutorial here.

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now known around here as Pat Foster
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http://www.patfosterguitars.com

Nice tutorial Pat. Great timing too. I'm planning on making one next weekend. Couple of questions for you though. Is the nylock nut large enough to grip comfortably or would something larger work better? And, where did you get your acrylic from?

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Aoibeann

Todd,

Wow. I hadn't heard about acrylic exploding. True, Lexan or   another polycarbonate-based material machines much more nicely and is orders of magnitude stronger.

Lillian,

The adjuster should move freely when the lock screws are backed off, so the nut should be OK. This assumes that all the holes are drilled with some accuracy and are well-aligned.

I found some acrylic at a garage sale a few years ago and went with that. Kept the cost for this project under ten bucks. There's probably a lot of vendors who sell online. Good luck with your project!

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now known around here as Pat Foster
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http://www.patfosterguitars.com

Acrylic has one advantage over polycarbonate. It's stiffer. Poly "gives," which is probably one reason it doesn't break easily. You have to be a bit cautious when using it in building jigs. If it's weight-bearing or long-span, it needs to be reinforced.

I have read that acrylic can behave like that, but I have never had anything that drastic happen myself. I use the band saw, table saw, drill press, sanding belts and sanding disks and the worst I see happening is that the heat generated by sanding can melt the edges a little. You also have to be gentle when you drill or you can get bad blow outs; I think there are special drill bits for the material but ordinary bits work too, just drill from both sides. Look out for the spiral debris that develops when you drill; it gets hot, so wear goggles.

I have a lot of 15 mm acrylic scraps, and I have used these to make several jigs and fixtures (including a version of this circle cutting jig, posted earlier this year). I am reluctant to recommend using it because of the horror stories I hear even if they don’t match my experiences, but what I do like about it (besides the fact that I have a big pile that I got for free!) is that it is so perfectly stable, strong and clear.

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Rian Gitar og Mandolin

Arnt,

I must have had yours tucked away in the cobwebby corners of my mind too. Yours gets a nice small minimum radius and a wide range of adjustment.

I just realized that with both blocks readily adjustable, there's the added benefit of loosening set screws for both, doing a quick, rough adjustment, locking the unthreaded block and using the fine adjuster to dial it in. Mine's getting an upgrade!

BTW, I've added a precaution about acrylic on my web page.

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now known around here as Pat Foster
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http://www.patfosterguitars.com