CNC - angled cavities possible?

[Knarbens]

My goal is to build a guitar with help from a CNC maschine. It's a project of me and a good friend of mine. I got a few questions. First we wanted to go with a flat top style guitar, but later we decided to do an arched top as it's some more attractive. The flattop design we first came up with didn't have a neckangle as it was meant to be equipped with a strat style vintage tremolo.

Now, when we wanted the arched top I modeled the body and simply raised the pickupplane and gave it a little angle, so the construction would be the same in general but with an arched (angled) top instead.

Now I wonder if it's possible to cut the cavities like pictured below.
By hand it wouldn't be a problem, but with a CNC machine?
Help would be much appreciated ... more pics to come.

 

[dougk]

There's only two ways to do this and retain 90* walls:

Angle the entire body on a sloped spoiler board or with a 5axis CNC. I have the same problem when I route my pickup plane and pickups keeping the routings at a 90* to the pickup plane. I built a spoiler board:

You can see my angled spoiler board under the Korina.

 

[Knarbens]

Thank you Doug!
So you cut the body in several passes? That's one idea I expected, but thank you anyway for the pic.

 

[pinefd]

I use a similar kind of a setup as the spoiler board for my overarm router, but mine's "adjustable":

Frank

 

[ihavenofish]

my mill has a swiveling head. in this picture its cutting the headstock shape at a 6.8 degree angle. most routers wont have a swivel standard, but you can make one fairly easily with a few aluminium plates and a steel pin.

otherwise, you need the angled jigs as has been shown already.
both methods ahve plus and minus points about them.

 

[Metamatic]

I use a similar kind of a setup as the spoiler board for my overarm router, but mine's "adjustable":

Frank

Nice board solution and nice setup Frank.

 

[popp]

I use a similar kind of a setup as the spoiler board for my overarm router, but mine's "adjustable":

Frank

Everytime I see a picture like this I'm so jealous. Why aren't these pin router tables available in Germany / Europe? I could import one but it's a hell of a lot money... I could also get a 2 ton massive pin/copy router here... but this doesn't make any sense since my workspace is in the basement

 

[landsharkey]

Everytime I see a picture like this I'm so jealous. Why aren't these pin router tables available in Germany / Europe? I could import one but it's a hell of a lot money... I could also get a 2 ton massive pin/copy router here... but this doesn't make any sense since my workspace is in the basement

Have you looked for an old radial arm saw? With not too much effort you could mount a router -

 

[LG2]

You can also program the taper in the milling pocket to get the angle this way no carriage taper is necessary.

[ame="http://www.youtube.com/watch?v=IxovV5GQYPk"]pockets[/ame]

 

[pinefd]

Have you looked for an old radial arm saw? With not too much effort you could mount a router -

I'm thinking maybe even retrofit a drill press with a router, which would give you the ability to raise and lower the router as well.


Frank

 

[ihavenofish]

You can also program the taper in the milling pocket to get the angle this way no carriage taper is necessary.

pockets

it wont do an under cut though and would need a small ball nose bit and generally be inefficient. certainly workable though and possibly the only good option if your cnc doesnt have alot of height for an angled jig.

the one thing you learn when you get into cnc is that finding a way to hold down the work is 90% of the job.

 

[popp]

I'm thinking maybe even retrofit a drill press with a router, which would give you the ability to raise and lower the router as well.


Frank

Thank's,

yes, that's exactly what we do...
I've borrowed this pic from a German luthiers forum:

 

[landsharkey]

I'm thinking maybe even retrofit a drill press with a router, which would give you the ability to raise and lower the router as well.

Frank

Or even a scroll saw (if the arm was stiff enough) used with a plunge base router. Many of the old Craftsman radial saws were recalled and Emerson would give $100 if you sent them the motor. So, if you find one of those and you already have a router, it shouldn't cost anything to try.

 

[dougk]

You can also program the taper in the milling pocket to get the angle this way no carriage taper is necessary.

pockets

I do this for things like Firebirds and such but on my guitars that have the top milled on an angle (like the pickup plane) the subsequent routings will no longer be at 90* with that plane. I'm anal that way