Machining Calculators & Engineering Tools
21 free calculators we built because we use them — tolerances and fits, threads, feeds and speeds, materials, inspection. Every one computes from formulas shown on screen, works in both directions, and tells you honestly when a number is exact and when it is an estimate. Results are linkable, so you can send a colleague the exact answer.
Tolerances & fits
Getting the numbers on the drawing right — and knowing what they cost.
ISO 2768 General Tolerances
Permitted deviation for any dimension — or the reverse: does the general tolerance cover what you need?
ISO 286 Limits & Fits
H7/g6 to H7/p6: exact limits, clearance/interference range, fit diagram and a measured-parts checker.
Press Fit Force
Lamé equations: contact pressure, press force, hub hoop stress and the shrink-fit temperature.
Tolerance Stack-Up
Worst-case vs RSS side by side, per-feature contributions, and the per-feature budget for an assembly limit.
True Position (MMC)
TP from measured coordinates with bonus tolerance at MMC, drawn on the tolerance circle.
Materials & stock
Choosing the grade and knowing what it weighs — before the quote.
CNC Material Selector
Filter 50 grades we machine by strength, machinability and density; compare side by side; look up alternatives.
Metal Weight
Bar, plate, tube and hex weight across real grades — or how much material fits a weight budget.
Thermal Expansion
Growth with temperature, and how much temperature swing a tolerance can survive. Why 20 °C is the law.
Threads & fasteners
From tap drill to torque wrench.
Tap Drill & Engagement
Tapping drill and ISO 273 clearance holes M1.6–M30, thread engagement worked both ways, full chart.
Thread Dims & 3-Wire
Pitch/minor diameter and measurement over wires — plus measured-over-wires back to actual pitch Ø.
Bolt Torque & Preload
M3–M30 in 8.8/10.9/12.9 with adjustable K and utilisation — reproduces the published charts and shows why they disagree.
Cutting: speeds, power & time
The shop-floor numbers, checked against our actual machines.
Feeds & Speeds
RPM, feed, chip load and MRR with chip-thinning warning — checked against our real spindle list.
Cutting Power & Torque
kW from removal rate and kc, torque at RPM, and which of our spindles can carry the cut.
Machining Time
Cycle time with a visual cutting-vs-everything-else breakdown — and the feed needed for a target time.
Turned Finish (Ra)
Theoretical Ra from feed and nose radius — or the max feed for the Ra on the drawing.
Scallop & Stepover
Ball-nose cusp height from stepover and back, drawn to scale, with the cycle-time consequence.
Setup & inspection
On the surface plate and at the machine.
Bolt Circle (PCD)
X/Y coordinates for any hole pattern, drawn to scale — or PCD from the measured gap between holes.
Sine Bar
Gauge block stack for any angle and back, with the real resolution at your angle drawn on screen.
Taper
Angle, ratio and taper-per-foot from diameters; 7:24 and metric ratios; tailstock offset.
Surface Finish Converter
Ra ↔ RMS ↔ Rz ↔ N grades in any direction, with honest confidence labels per conversion.
Cost & DFM
What your part will cost — and why.
Send Your Drawing for a Same-Day Quote
Talk directly to the engineers who will machine your parts — no account managers, no trading-company markups. Complimentary DFM review with every enquiry.