Home / Metal cutting
Three operations, one idea
The surface finish is specified on the drawing before any process exists. So the calculation starts there, and feed comes out of it rather than going into it. Each operation has a calculator to use and a reference to read.
Turning
The operation where the finish model rests on real geometry — a nose radius from the ISO 1832 steps, no assumptions. Also where the tool life economics live: two runs at different speeds give you the Taylor exponent for your own machine, and from it the economic and maximum-production speeds.
Milling
Feed per tooth back-solved from the ISO 1302 finish grade, then chip thickness through the real engagement arc rather than a flat approximation. The corner radius is an honest placeholder here — face mill inserts carry a wiper chamfer, not a true radius, and the page says so.
Drilling
The operation with the fewest levers and the least forgiveness. Two lips split the feed, the point angle thins what remains, and cutting speed falls to zero at the chisel edge. No surface finish model, deliberately — hole finish comes from margin condition, runout and chip evacuation, not from feed and a corner radius. Through or blind changes the problem more than any parameter does.
Tool materials and geometry
Carbide and HSS speed ranges across all five ISO 513 groups, and why edge geometry — not the grade — decides chip formation, evacuation, cutting forces, vibration and finish. Plus the Taylor exponent ranges used to sanity-check a tool life test rather than substitute for one.
What the calculators do differently
Three things, and they are the same three on every operation.
Finish drives feed
Not the other way round. Pick the ISO 1302 grade the drawing specifies and the feed is derived from it. Every other calculator asks for a feed and stays silent about the surface you end up with.
The setup is scored
Piece, mount and tool robustness, machine rigidity, interrupted cutting, skin and material condition. They decide which finish grade is realistic and then scale the cutting speed. Catalog values assume conditions your shop does not have.
Limits are stated
Where a derived feed drives the chip under the rubbing floor, or exceeds the nose radius, the tool says so. Where a model is a placeholder, the page says that too rather than reporting a confident number.