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Anyone in SOCAL with a CNC machine setup? I need to get a few specific radius boards cut but not in the mood to do it myself the hard way and lengthy way.

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Peter M.
Cornerstone Guitars
http://www.cornerstoneukes.com

Oh, I didn't mean fretboards.... just some radiused dishes and other radiused stuff..

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Peter M.
Cornerstone Guitars
http://www.cornerstoneukes.com

Hi Peter - you could try asking on the CNC part of the forums at sawmillcreek.org - there are lots of guys on there with CNC machines, and I'm sure there are several in SoCal.

Cheers,
Dave F.

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Cambrian Guitars

"There goes Mister Tic-Tac out the back with some bric-brac from the knick-knack rack"

That isn't a small job, unless they have run them before. CNC isn't automatic, every tool path has to be programed. You probably know that. CNC is fast for the second one...

I cut all my boards on a lathe, the only downside/upside is that I found it had to be birch plywood, or marine. That is more expensive than MDF, but better in every other way, as far as I can tell. You need a guy with a big lathe, but those are relatively common and I guess it increases your chances of finding someone. The lathe made very accurate boards. CNC can theoretically do stuff to very close dimensions, though I would be skeptical of that in all cases. Cutters affect amounts actually taken away, wood moves as it is cut, wood moves after it is cut. These things are not going to be to the thou. But a turned board will be light free against a measuring arc. And it takes very little time to do different sizes and shapes on a lathe. With one arc form I made dishes, suction fittings, guitar shaped forms, the works, no set-up or programing.

Tom, I don't think you have spent too much time around CNC by those comments. When I made dishes on my powered rim sander I had to make a new set of rails for each dish size. Now, with my CNC it takes me 2 minutes, yes, 2 minutes! To draw, build the tool path and save a new radius. My stepovers when milling are about .020" with a 1" ballnose cutter with a 1/2" shank mounted to a $3,000 spindle....no tool deflection in any of that! The disc (double laminated MDF) is vacuum clamped to the CNC table so it does not move throughout any of the machining process. So, all of your assertions are not founded in the actual process from my experience. Is CNC better than a lathe? I wouldn't say that it is or isn't. It all depends on how much time you have and how good you are on a lathe or any other method. There are lots of ways to skin this cat and if the end result is a the product you want then there is no BEST way. As for plywood versus MDF, I could and do either but prefer MDF for dishes, it machines well, is very stable once it is laminated and it's extra mass is a benefit for sanding dishes. Any manufactured board will have a hardened surfaces (mdf, plywood, plexiglass etc.) so if you remove just one of those surfaces you have added stress to the board and it will distort (speaking from years of experience with this stuff) so that is why I pre-laminate discs prior to milling them into dishes.

Shane

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Canada

Interesting discussion in that I machined radius dishes for flat-tops about 10 years ago on a CNC lathe. It was a large swing shopbuilt faceplate lathe combined with a little Maxnc mill mounted on a long slide with stepper motor then in turn mounted to the lathe. I even rough machined some of my early archtop plates on this setup but only to the extent of ball nose milling enough "splines" to define the length and width arches and then carved to those "splines" by hand. The spindle of the lathe was controlled with one of the tiny steppers thru a hi-reduction miniature gear box. A friend helped me out by writing an Autocad Lisp routine to convert rectangular coordinates to polar coordinates. Talk about doing things the hard way!
Nelson