Speed & Feed

Standing at the machine working out spindle speed in your head? Speed & Feed turns cutting speed, tool diameter, flute count and chip load into the RPM and feed rate you actually key into the control — recalculated as you type.

HOW IT WORKS
Pick milling, drilling or turning. Choose a material and tool type to load a conservative starting point, or type your own cutting speed and chip load. Enter the tool diameter and flute count. Spindle RPM and feed rate update immediately, in metric or imperial.

WHAT YOU GET
- Spindle speed from surface cutting speed and tool diameter
- Feed rate in mm/min or inch/min, with the correct formula per operation
- Milling, drilling and turning, each handled differently rather than lumped together
- Material presets for aluminum, brass, mild steel, alloy steel, stainless, cast iron, titanium and plastic
- Carbide and HSS, with separate starting values for each
- Optional machine limits that flag a result your spindle or axes cannot reach
- Save up to 10 recent calculations and reload any of them
- Metric and imperial, switchable without losing your inputs
- Works without an internet connection for the calculation itself

TURNING IS NOT MILLING
Feed per tooth times flute count times RPM is a milling formula. On a lathe the tool is a single point and feed is per revolution, so multiplying by a flute count is simply wrong. This app switches the formula with the operation and changes the input label so you are entering the quantity that belongs to the cut.

WARNINGS, NOT SILENT CLAMPING
Enter your machine's maximum spindle speed and feed rate and the result is flagged when it goes past them. The true calculated number stays on screen. An app that quietly trims 15,000 RPM down to your 8,000 RPM limit hides the fact that your setup cannot run that tool at that cutting speed — which is exactly what you needed to know.

BUILT FOR
- Machinists setting up a job on a mill or lathe
- Hobby and benchtop CNC users working out where to start
- Shop apprentices and students learning how cutting speed, diameter and chip load pull against each other
- Anyone who wants a second opinion before committing to a first cut

HOW THE NUMBERS ARE CALCULATED
Spindle speed is RPM = 1000 × Vc / (π × D) in metric, and RPM = 12 × SFM / (π × D) in imperial. Milling and drilling feed is RPM × flutes × feed per tooth. Turning feed is RPM × feed per revolution, with no flute term. Unit conversion keeps the physical quantity intact when you switch between mm and inch.

NOTES ON SCOPE
The built-in material values are conservative starting points for getting a cut going, not optimized production parameters. Your tool manufacturer's published data for the specific cutter, and the rigidity and power of your own machine, come first. Depth of cut, width of cut, coolant, workholding and tool condition all change what is safe to run, and this app does not model them. Always confirm against the tool maker's recommendations before cutting.