Official Luthiers Forum!

Hey guys,

I have another noobie question: how to mill pockets in radiused fretboards? When I hand rout I follow the radius with my little router base. Most of my inlay work is multi-piece so I assemble the parts to follow the radius of the board.

Do you guys rout your pockets flat and then radius after?

BTW my Xylotex did finally die with a pop and release of the magic smoke. I got swamped with other things but finally shelled out for a G540 just recently. It totally rocks! I love it!

I'm even still using the old 24V power supply. I'll get a 48V one at some point. My rapids are maxed out at 37.5 IPM because I'm still running 25khz on the laptop. But that's way faster than I had before and no stalling or bad noises.

And yes, Cyborg, thanks to the G540 I now have a breakout board.

...Athena

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If you don't have enough material to reach around the radius then you can mill the pockets at different depths for each piece. I've only had to do that once, though. In general the pockets are flat and the shell is leveled flush to the radius after installation.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Hmmmm. I've never done anything flat. Most of my materials are .060" down to .040". Wood isn't really a problem. Shell I'm concerned about because it gets translucent when it gets really thin. Metal can get super thin but I rarely buy it very thick. Precious metals I rarely buy larger than .040" (18 gauge).

I tried to draw it up in Illustrator. For a 10" radius board at the nut end I'd have around .026" left on the sides. At the large end I'd have... pretty much nothing.

I guess I'll be milling pockets at different depths.

Thanks,
...Athena

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Great site Athena - really nice work!

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http://www.PeakeGuitars.com

Thanks Trevor! You've done some lovely stuff yourself.

...Athena

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What about making a plug with a radiused top that you install at the bottom of the pocket?

Interesting idea. I guess that could be a fallback, particularly if I have a lot of little pieces.

I'm also wondering if a trunnion table would do the trick, provided I had CAM software to drive it. I have a Sherline rotary table and an extra motor for it. I'd like to set one up at some point in the future.

BTW Stunning instruments!

Thanks,
...Athena

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My method is an indexing vacuum fixture. I tilt it a predetermined number of degrees either direction when doing fboard inlay which helps ensure maximum remaining thickness of the pearl. It's made from 1"x3"x12 ga. (approx.) aluminum tubing about 20" length with the ends plugged. The plugs are each drilled to provide the center of rotation which happens to be at the center of the 1" tubing "thickness". The end trunnions are 1x3 solid alum stock.
I use the same fixture set in the flat position for machining the fret slots with circular tool paths using an endmill cutter. The fretboard perimeter is cut to size and taper as the last op.
Nelson

Athena I have a couple of questions for you.

1. What is the deep red material used in the cobra inlaid board on your site, assuming you can or will share that info?

2. Do you radius the bottom side of your inlays to fit the radiused bottom of the pocket if it is to be cut on a trunion table? I understand your need to keep the shell from getting thin on a flat bottom. If your are laying in small seperate pieces on a radius, seems like the multi step bottom would work as well.

Mike

Wow that sounds interesting. I'd love to see a photo of that, but I understand if you don't want to show it.

I'd love to have some vacuum fixtures. I have a little V-clamp I might play with.

Thanks,
...Athena

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Of course I'll share. I've gotten lots of good help here so I always want to give back.

It's dyed stabilized wood. Some is maple burl, some is box elder burl. I use it a lot. Everything on the cobra that's not shell, gold or silver is various colors of dyed stabilized wood. Sorry I don't have pics of the board completely levelled yet. I'm still waiting on the builder to glue it to the neck. The customer picked a new neck blank.

This is not pentacryl BTW. It's an acrylic-like solution forced into the wood under vacuum. Knife and pen makers have been using it for a long time. Most of what I use are knife scales/blocks and large pen or reel seat blanks. Bass builders have been using stabilized tops and fretboards too. I won't use light woods like maple on rosewood and ebony boards (no finish) - but I can use stabilized maple, box elder, holly, buckeye and other light woods as inlay materials without fearing they'll end up grey and ugly.

As an inlay material this has been kept a secret by some other builders - though the bass builders are quite open about it. I think more demand will only stimulate production. The prices have already increased, can't avoid that. I just want more options and more colors.


I follow the method outlined in Larry Robinson's videos (and years of e-mail pestering ). The individual pieces are flat. I keep the pieces small across the board and carefully glue them together on wax paper over the actual radiused fretboard. That gives the whole composite inlay a radius... of sorts. ;-> It's not perfect, but it works.

For CNC I will probably do multi-step pockets. I've only been cutting a few inlay parts and misc small wood items for my builder friend so far. I'm going to design a first test multi-piece test inlay and rout an actual test fretboard soon. I just have to decide what I want to do...LOL. The hardest part.

...Athena

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