Machining
Machinist calculator: speeds, fits and threads
Cutting speed and feed, ISO 286 fits, threads and tap drills, tightening torques, bolt circles, tapers, measuring over pins, hardness, surface finish and machining time: the machining calculations of Metalary.
This page gathers the 10 machining tools of Metalary and 3 reference charts. Each tool page shows a worked example with the default values and cites its sources; results are indicative.
Tools · Machining
Cutting speed and feedN, Vf, power and removal rate for turning, milling and drilling, with catalogue starting values.ISO 286 fitsHole and shaft limits, clearance or interference, any class a to zc up to 500 mm.Threads and tap drillsTap drill for cutting or forming taps, pitch and minor Ø, depth: M, UNC/UNF, G, Rp, Rc, NPT.Tightening torquesTorque and preload of a metric bolt by class and friction (VDI 2230), minimum preload by method.Bolt circleX/Y coordinates of n holes on a circle or arc, hole spacing, full-size marking template and DXF.TapersTaper ratio, angle, compound setting and tailstock offset; Morse, metric and chuck tapers.Measuring over pinsThree-wire measurement and best wire; over-pin measurement of a male or female dovetail.Hardness conversionHRC, HB, HV, HRB and tensile strength of steels, from ISO 18265.Turning surface finishTheoretical Ra and Rz from feed and nose radius, max feed for a target Ra, N classes.Machining timeCutting time for turning, facing at constant Vc, drilling and milling, per part and per batch.