[denvermatt]

EDIT: Never mind about this issue. Upon further investigation it looks like the chuck I'm using to center my table isn't true, and so therefore the table wasn't as centered as I thought it was. I'm pretty sure my original way of calculating the radius was the correct method.

I thought the answer to this was obvious, but for some reason it isn't working out.

I'm trying to cut a hole that is 0.865 inches in diameter.

I have a 0.75 inch endmill and a rotary table.

I thought the way to do this was to center the endmill over the center of where I want the hole to be, then move the table horizontally by 0.058 inches, and rotate around the axis.

I arrived at this number by subtracting the radius of the endmill from the radius of the hole or...

Offset = hole.radius - tool.radius

However, the diameter of the hole I'm getting with this method is approximately 0.807 inches in diameter (Too small). I've tried this several times, and have gotten the same result each time.

So, then I thought, ok, the difference between 0.807 and 0.865 is 0.58. So, maybe I should just double the radius difference and move the table over 0.116 inches.

Offset = 2 * (hole.radius - tool.radius)

When I do that my hole is 0.92. Too big!

I look at that number, and it is approximately 0.055 too big. So, that's pretty close to my 0.058 that I calculated for my radius difference. So, I thought, EUREKA! I need to half the radius, and add that to the radius, and that will give me my offset.

Offset = (0.5 * (hole.radius - tool.radius)) + (hole.radius - tool.radius)

When I do that my hole is 0.878. Too big again!

I'm completely stumped. Do any of you guys know how to calculate this?

[Fastest1]

NVM