engraving a fixture.

May 05, 2006 4 Replies

Hello, I am new to the forums here.



Today a was asked to engrave some curves in a model. 3mm wide



what they want me to do is use a ball nose cutter, and cut on the line. no problem



the problem is I dont have a 3mm ball nose endmill. I have a .250in ball.



what would the formula be to set the depth to get a .118in wide cut.?



Courtesy of the Machinery's Handbook, 24th Edition, page 58.

h = r - 1/2 times the square root of (4r squared - c squared)

h is the depth you seek

r is, of course, the radius of the cutter

c is the chord length, .118 in your case.

Later,

Charlie

Without putting too fine a point on the obvious, just buy one.

your depth of cut is going to be much shallower than it should be. .058 vs .0148

Or how about a smaller ball and move it over. Take a center cut and then move half of the diameter difference to each side. It's really difficult to tell it's a bullnose instead of a half round

Will

the cut is just meant to be a visual check, go/no-go on the model, 3mm trim tolerance. depth is unimportant.

thanks to all for the help, jobs done now, and looks great.

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