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Looking for some suggestions on holding a fretboard blank. I want to be able to cut to size around the perimeter. radius them cut fret slots in one operation. I have a ATC so changing bits is no problem. I do too many to use double face tape so vacuum seems to be the only option. Any suggestions. TIA

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Beautiful and unusual tone woods at a reasonable price.
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The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

I've had good experiences with vacuum hold down and locator pins - one in each end of the fretboard blank.

With that scheme I've been able to radius, cut fret slots, inlays or position markers, and cut the taper down the sides, but I've been cutting the ends off by hand.

If your priority is to cut out the fretboard completely, including the ends, then perhaps tiny locator pins on the underside of the fretboard blank which don't go all the way through could work.

I assume you have tried the obvious: double stick tape? That is what I use for radiusing, cutting fret slot, inlay, and profile (in that order usually). I admit that I have never taken the blank off the table and then tried to index it back for a second round of cutting. Is that what you are trying to do?

I use vacuum as well and while I do have locating pins, I hardly ever use them as it takes too much time to cut them on the backs of the fretboards. Instead I use needle plates which keep them from squirming.

Full Disclosure - I also sell these needle plates on my website. I'm continually amazed because they are absolutely amazing to prevent vacuumed parts from squirming yet I've only sold a handful of them. I guess most people just don't understand

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Too time consumong when you have a lot to machine.

_________________
Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

Leo what are you using for vacuum pump. Would you have any pics of your setup?

_________________
Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

Our blanks are prepped with counter sunk holes on center at each end, boards are then fastened to the machine bed with aluminum or brass screws. Same holes are used to locate for contour and fret slot operations.

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Ken Cierp

http://www.kennethmichaelguitars.com/

Ken so you rough thickness the blanks before drilling the holes? Is your bed mdf? If so
won't the screw holes wear out and not hold after a while?

_________________
Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

I use a vacuum holddown with three 1/8" brass index pins that align the rough boards to the jig. The fingerboard blank is flattened on the back side, three index holes drilled about 1/8" deep. These same index holes are used for alignment to the neck later on, but at this point they lock the blank onto the clamp. Since I don't have a tool changer, I'll run several boards through a given operation, then set the next operation up and run them all again. The index pins keep everything in line over multiple operations. I surface/arch the boards, slot them, cut inlay pockets and cut to final profile on the same vacuum setup. I just use a small continuous running Gast pump for vacuum.

Dave

Bob -- the boards are surfaced one side. For many of our parts we use job specific pallets on top of the machine bed, the pallets are interchangeable for our three machines, the pallets have threaded inserts.

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Ken Cierp

http://www.kennethmichaelguitars.com/

Bob good ideas Ken and Dave. Dave I use the same setuo and software as you do. Right now I have been using VCarve Pro and Rhino. I do radius the fret slots so I would like to be able to drill for pin holes in one operation then cut outline, radius top, cut fret slots in Rhino. After I get done with this batch that has to go out the door on Mon. I will be back to pick your brain.

_________________
Beautiful and unusual tone woods at a reasonable price.
http://www.rctonewoods.com/RCT_Store
The Zootman
1109 Military Rd.
Kenmore, NY 14217
(716) 874-1498

I think the lightbulb just went on for me regarding your needle plates. I've seen you post about them before but for some reason the idea just didn't stick in my head.

Now that you've mentioned them in this context it sounds like I could be saving myself from having to drill indexing holes on the back of every fretboard, flip them over and pin them back into the vacuum jig, and cut the front. Could be a significant time saver.


Do you mind sharing any photos or just the number of needle plates you use for fretboard hold-down? Is a couple at each end enough?

I'm pretty sure I'm going to have to buy some from you.

I've never had to use more than two plates on any part I've cut, be it fretboards or whatever. For fretboards I use the .5mm plates.

Here's a shot of my fixture





If you need the alignment pins anyway it doesn't save time but if you don't, it's a no brainer.


Sent from my iPhone using Tapatalk

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

I used to use two shallow pin holes on the backs, with 1/8" pins in them, on the vacuum fixture. As an inlay guy, I had a lot of broken off carbide micro-mills, so I drilled a few deep holes in my fixture and used them as no-drill indexing pins.

The needle plates didn't exist for purchase back then. If I were doing it now, I'd just buy a couple of those for my fixture. They barely cost more than the little cutters I was breaking!

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Hey Andy, what do you call the material that your vacuum jig plate is made from?

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Allen R. McFarlen
Barron River Guitars & Ukuleles
Facebook
Cairns, Australia

That stuff is something called Tooling Board from General Plastics. A bunch of companies make it and the stuff is fantastic. I use the 40lb / ft^3 stuff. It's important to find a local supplier because shipping is usually pretty high.

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http://www.birkonium.com CNC Products for Luthiers
http://banduramaker.blogspot.com

Thanks. Living in the very north of Australia, nothing is local. So I'll have to look way down south in Brisbane perhaps.

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Allen R. McFarlen
Barron River Guitars & Ukuleles
Facebook
Cairns, Australia

Andy,
Can you make me one of these? for one single fingerboard only. Ship to TC MI.

I will email you.

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Ken

The fixture from my past life was much like Andy's pic, but held more boards.

It was made from phenolic, and the height was a bit higher than Andy's. Basically, they were suspended 3-4" above the phenolic bed so that the spiral bit could come in and cut the taper without wrecking the platform beneath.

They were held in place with vacuum and 1/8" index pins.

They were thicknessed on the wide belt first, which just makes sense to me.

I thought that using the CNC to cut the index holes might have been a bit of a time soak. I'd have thought that a jig with drill guide bushings and a drill press could get through a pile of boards faster than having to load the machine, run, and unload. But I guess it depends on machine speed.

I used the same fixture to drill the holes and to machine the boards, I just took the index pins out when I was cutting the backs of the boards. You can get cooking pretty fast when it takes five seconds to reload the vacuum fixture and two seconds to drill the holes. You can also hold necks on the exact same fixture plus possibly a support for the headstock.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Another thing to keep in mind is that if you use pins to hold your fretboards down to a vacuum fixture....those same holes can be drilled into your necks in order to register the fretboard to the neck while gluing.

Doing this registers the fretboard and fret slots to the neck cad model....which can't hurt the process of achieving good intonation any.

I'll snap some pictures of my method today.

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic