Machining & Metalwork

Machining and metalwork calculators

These machining tools give you a fast, free sanity check right at the machine, calculated instantly from proven formulas — no spreadsheet, no login, nothing to install. Whether you are a hobbyist or a shop machinist, they are the numbers you look up every day, in one place.

Which one do you need?

The four RPM calculators — Drilling, Tapping, Milling and Turning — all work from cutting speed and diameter, and each already knows a sensible cutting speed for eight common materials, so you choose the material instead of looking a number up. Milling adds feed per tooth and a ball-nose or tapered cutter option; Turning adds feed per revolution. Band saw speed calculator and Circular saw RPM calculator do the same for sawing. Bending force calculator gives the tonnage a press brake needs from material, thickness and die opening. Tap drill size chart gives the hole to drill before you tap, metric and imperial. Metal weight calculator turns a shape and a material into kilograms and a price. ISO tolerance & fit calculator gives the actual limits behind designations like H7/g6.

Common questions

Where do these numbers come from?

The formulas and the material table come from a workshop calculator its author used on real machines for years, not from a competitor’s website. The ISO fit figures are the published ISO 286-2 values, embedded as measured tables rather than approximated from a formula, because a tolerance rounded to the wrong micron is worse than no tolerance at all.

Metric or imperial?

Both — one button switches every field and every label. The arithmetic always runs in metric underneath, and the unit choice only changes what you see and type, so the result cannot drift depending on which system you happened to pick.

Can I run these numbers straight on the machine?

Treat them as a starting point. They are calculated correctly, but no calculator knows your machine’s rigidity, your tool’s condition or how the workpiece is clamped. Start with a light test pass and work up to the sweet spot. Every one of these pages carries the same safety note for exactly that reason.

Do the coating options make a real difference?

Yes, and the calculators reflect it. A coated tool takes roughly a third more cutting speed, and for milling the feed per tooth rises with it, since spindle and feed move together. For turning we raise the speed by a third but the feed by only fifteen per cent — the conservative middle of the range manufacturers publish. Start there and work up rather than jumping straight to the maximum.