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I've used fixtures like Dave's (screws and a carrier plate) for parts other than guitar necks, but it's a good way to do things. Like Rand says, using a three-sided fixture is a giant hassle and I only used one when I was doing high production acoustic necks. It's totally not worth it for electric necks, nor anything less than 'I'm gonna machine nothing but necks all day for a week'.

For blanks, I started with jointed one side, then a drilling jig, then a jointer jig indexing off the drilled holes to cut the headstock angle. Way under a minute per blank when batched.
Then on the CNC to face mill the 'back' side, then flipped to cut the truss rod slot. Face mill's faster than a planer or jointer, and never snipes. Both ops, total, are under 30 sec including swapping blanks.
Then heels were glued on and they went through the three operations on the fixture. I used a shaper cutter in the CNC to take off the stock the band saw would have.

If I were setting up for lower production, I'd joint the back of a blank, use the CNC to face the other side and cut the headstock angle/index holes/truss rod slot, then flip it, glue on the heel, and machine the whole thing face-down. Tuner holes and finish machining the headstock shape were done in a fixture that indexed off the rough shape of the headstock shape from the first round machining. That's what I did for electric necks (without heel gluing), and I was doing better than five necks per hour from rough blanks. That was with no special cutters, just balls and straights. You could beat that easily with fancy cutters.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

bump

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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

Bump for what? where's your necks Bob?

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Ken

Well I thought maybe turmite forgot about me so bump as a reminder

_________________
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

Bob, I got an email from Turmite and he is on the road and back soon, but has some church activities until Wednesday.

How much Z height does your machine have? (edit i re-read it and see it is 8 inches)
Are you going to machine the whole neck or just the underside?
Do you have a vise for holding the blank while you machine the fingerboard side and angle?
If not you can use conventional tools to do this operation to your blank and use a table saw or router to rout the truss slot. And then make a holding jig like shown earlier in the thread. You will just need the toolpaths for the back of the neck then.
How good are you with Rhino? If this is new to you then you can start by loading your neck into Rhino and learning to spin it around in perspective view and zoom in and out. Work on moving the neck around in the different views. Learn to go from each view back to the four standard views.
After this you can try to rotate the neck. Make sure your units are set in properties to inches or if you are using mm set it that way.

I am far from a teacher but you can start by making a template of your neck.
1. Open file in Rhino
2. Change properties to have your units set in inches.
3. Look at the neck in your 4 views and make sure it is oriented "correctly", by this I mean not sloped, slanted in space. It should sit parallel with your grid in the side view. If not fix it.
4. maximize the side view.
5. now you can route this shape from some MDF or plywood.
6. move your neck so it is near the X-Y-Z Zero.
7. maybe rotate the neck so it is longer in the Y (learn to do this operation of rotating 90 or 180 degrees etc...
8. Perform the madcam toolpath using profiling.
9. Once you have the Gcode. load it into your router software and practice cutting this profile.
You can use this profile to draw on your blank and to make the headstock ramp jig.

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Ken

Thanks Ken I am going to try and run that profile. The neck looks fine in every view.

_________________
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

Hi Bob and Ken.......nope, haven't forgot. Just got in this afternoon after a 7 day 6 state venture to move a 3 bed household from Wisconsin to Mississippi for the sister of the lady I am dating. It has been a long arduous ordeal and very tiring for a 62 yr old spring chicken! Tired to the bone is what I am. Hopefully later today as in the afternoon I can take a breath and begin the process.

Mike

Turmite ... Thank you so much for the time and patience you took to help me with my project. A few more glitches that I am working out. Couldn,t have done it without your generous help.

_________________
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

Mike if you read this I need to talk agin. Cant find your number
got it

_________________
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

Bob, did you get your neck going? I haven't been on the board much lately, so I didn't see your post until this evening. I use the latest versions of MadCAM and Rhino and am milling my acoustic necks on a K2. Took quite a bit of trial and error to get the process working, but the necks coming off the machine are quite nice.

I found holding the stock down to be one of the more challenging aspects of milling a neck. I initially tried to hold the neck blank down with vacuum, but after having it pop off several times, I gave up and made a jig so I could screw the neck down. I have a routine that mills the truss rod slot and then drills two locating holes and 5 screw holes. The neck blank is then aligned and attached to a spoilboard with the six screws and the spoil board is located on another permanently mounted spoilboard on my table using locating pins and clamps. With the fixture saved in Mach 3, The most critical part of the process is getting the blank aligned for the truss rod and mounting holes.

I initially tried milling with a 5/8" tool, but found my collet simply would not grip it tight enough. So I dropped down to 1/2". I use a 2 flute carbide square end mill to rough then clean up with a 2 flute carbide ball mill. I have an 8" riser on my machine, so with 6" cutters, I can reach around the heel to mill. 6" cutters can be tough to find, and they are pricey. They are also a bit scary, having so much carbide dangling from the collet. I take lighter passes to avoid breaking the bits.

Below are a few pictures that will give you some idea of my process:

Truss rod slot and mounting holes milled. The screw holes at the outer ends are in waste areas, and the one in the center is for a small #6 wood screw that reaches into the neck just outside of the truss rod:
Locating the neck on the spoil board:
Screwing the neck to the spoil board:
Mounting the spoil board to the table. The board on my table is permanently mounted and is where I locate all sorts of other spoil board for clamping, e.g., bridges, braces, fingerboards. When I first got the machine, I had a spoil board on the entire table, but quickly realized I need to use the t-slots for other tasks, so I went with a dedicated spoil board on a smaller area:
Roughing out the neck with a 1/2" end mill:
Cleaning up with the 1/2" ball mill:
I could walk through my process in designing a neck in Rhino, but Trev already has a good toot out there. I can help answer more specific questions.

Ken

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http://www.casperguitar.com

Looks like you're getting good results, Ken, so congratulations! The only direct suggestion I can make to help you would be that you can get long cutters with shorter flute lengths; my favourite solid cutter was a 3-flute (though they come in 2 and 4), reduced neck 1/2" end mill with 1" of flutes and an overall length of 6". The difference in stiffness VS a full-flute cutter is absolutely night and day.

On the topic of getting long cutters at a decent price, the best prices on good cutters I've found are from USA Carbide or Ridiculous Carbide. The USA Carbide general purpose stuff I got many years ago was razor sharp, and you get similarly sharp cutters if you order cutters for aluminum from Ridiculous.

_________________
Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services