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Neck carving - corner radius or ball mill?
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Author:  Anthony Lembo [ Mon Nov 16, 2009 12:58 pm ]
Post subject:  Neck carving - corner radius or ball mill?
Hi everyone.

Any pros or cons when using a ball mill or corner radius mill for FB side down neck shaft and heel carving? Any preferences?

I can accommodate a 5/8" mill shaft, so I'm not too concerned about length.

I seem to remember some discussion regarding zero speed at the center of a ball mill being an issue for arched plate carving more compression/burnishing than cutting - is this an issue on mahogany?

Thanks!

Anthony
Author:  Bob Garrish [ Mon Nov 16, 2009 4:35 pm ]
Post subject:  Re: Neck carving - corner radius or ball mill?
A bullnose can't cut a concave surface without leaving a flat on the bottom, but that's the only reason you strictly couldn't use one for certain surfaces. A bullnose of a certain diameter is going to have a sharper corner radius than a ball of the same diameter, which is a strike against, and that means more passes to get the same smoothness.

While there is a burnishing in the center of a cut with a ball, there's very little material thickness being compressed as the cutting edges ahead of the center already take most of the material off before the center reaches a given point.
Author:  Parser [ Mon Nov 16, 2009 9:10 pm ]
Post subject:  Re: Neck carving - corner radius or ball mill?
Ball mill are the tool of choice pretty much everywhere I have seen CNC neck carving.

As usual, I'm with Bob on this..!

Trev
Author:  Anthony Lembo [ Mon Nov 16, 2009 9:10 pm ]
Post subject:  Re: Neck carving - corner radius or ball mill?
That makes sense. Thanks for your help Bob and Trev!

Constantly second guessing,
Anthony
Author:  rlrhett [ Thu Nov 19, 2009 12:28 pm ]
Post subject:  Re: Neck carving - corner radius or ball mill?
I hate to sound ignorant, but what is the difference between bull nose and ball?

Thanks,
Author:  arie [ Thu Nov 19, 2009 2:28 pm ]
Post subject:  Re: Neck carving - corner radius or ball mill?
rlrhett,

Look at these:

http://www.mcmaster.com/#end-mills/=4ko7um
would be an example of a "ball" endmill.


http://www.mcmaster.com/#end-mills/=4ko8gq
would be an example of "bull" nosed endmill.

while these are geared mostly towards metal cutting the concept is the same.
Author:  arie [ Thu Nov 19, 2009 2:38 pm ]
Post subject:  Re: Neck carving - corner radius or ball mill?
ok, well those links don't seem to work well.

So a ball endmill or cutter has a ball on its end that when it's cutting will produce a half round channel equal to its diameter. ie: 1/2 diameter -1/2 round channel, and a bull nosed cutter or endmill has a specific radius to it's end that is less then full round. When cutting it will produce a square channel with filleted corners. The advantage is that the ball cutter will profile a complex surface with 180 degrees of tangency to that surface.

here's some pics:
http://images.google.com/imgres?imgurl= ... n%26sa%3DX

and...

http://www.made-in-china.com/image/2f0j ... M-010-.jpg

hope all this helped [:Y:]
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