10-01-2013, 08:57 AM
In the formula Tom has given as "4 x cutting speed / cutter diameter" is for converting inch cutter diameter into feet. The constant derived by:
(Cutter diameter x pi)/12 (12 inches per foot)
It actually generates a constant of 3.819718634, so many people round up to 4. I use 3.82.
For metric cutting speeds and cutters, the cutters are usually given in millimeters and the cutting speeds given in meters per minute.
I wish I had time to figure out the simple formula for metric, but I'm sure it's out there.
(Cutter diameter x pi)/12 (12 inches per foot)
It actually generates a constant of 3.819718634, so many people round up to 4. I use 3.82.
For metric cutting speeds and cutters, the cutters are usually given in millimeters and the cutting speeds given in meters per minute.
I wish I had time to figure out the simple formula for metric, but I'm sure it's out there.