CNC TRUECUT / FREE SHOP TOOLS

Calculate a cutting parameter, lay out a hole pattern or check geometry without hunting through a spreadsheet. Choose a tool below for an input form, transparent formulas and a worked example. Metric and Imperial units are supported.

• Milling speeds and feeds — RPM = 1000 × Vc / (π × D); feed = RPM × feed per tooth × teeth.
• Drilling RPM and feed — RPM = 1000 × Vc / (π × D); feed = RPM × feed per revolution.
• Lathe RPM and feed — RPM = 1000 × Vc / (π × D); feed = RPM × feed per revolution.
• Radial chip thinning — Below 50% radial engagement, factor = 1 / √(4r(1 − r)), where r = engagement / diameter.
• Material removal, power and torque — MRR = depth × width × feed; net kW = volume in mm³/min × kc / 60,000,000.

• Tapping feed and pitch — Lead = pitch × starts; synchronous feed = RPM × lead.
• Thread lead and feed — Lead = pitch × starts; feed per minute = RPM × lead.
• Cutting tap drill estimate — Approximate cutting-tap drill diameter = major diameter − pitch.

• Right triangle angles — θ = atan(opposite / adjacent); hypotenuse = √(adjacent² + opposite²).
• Angle and missing side — Opposite = adjacent × tan(θ); hypotenuse = adjacent / cos(θ).
• Taper half and included angle — Half-angle = atan((D − d) / (2L)); included angle = 2 × half-angle.
• Fillet tangent geometry — Tangent distance = R / tan(θ/2); centre distance along bisector = R / sin(θ/2).
• Radius, chord and arc — Arc length = Rθ in radians; chord = 2R sin(θ/2); sagitta = R(1 − cos(θ/2)).

• Bolt circle coordinates — Spacing = 360° / holes; X = centre X + R cos(θ); Y = centre Y + R sin(θ).
• Partial bolt circle coordinates — Spacing = sweep / (holes − 1); both arc endpoints are included.
• Linear hole pattern — Xᵢ = X₀ + i × spacing × cos(θ); Yᵢ = Y₀ + i × spacing × sin(θ).

• Countersink depth — Axial conical depth = (large diameter − pilot diameter) / (2 tan(included angle / 2)).
• Centre hole conical depth — Cone depth = (large diameter − pilot diameter) / (2 tan(included angle / 2)).
• Drill point height — Point height = diameter / (2 tan(included point angle / 2)).

• True position coordinate check — Diametrical position error = 2 × √(ΔX² + ΔY²).
• Hole and shaft limits — Minimum clearance = hole minimum − shaft maximum; maximum clearance = hole maximum − shaft minimum.

• Length conversion — 1 inch = 25.4 mm; 1 foot = 304.8 mm.
• Unit conversion calculator — Convert inches, millimetres, kilograms, pounds, temperature and pressure with clear formulas.
• Material weight calculator — Estimate pounds and kilograms for round bar, tube, rectangular stock and hex bar using material density and dimensions.
• Scientific shop calculator — Supports +, −, ×, ÷, powers, parentheses, pi, e, sin, cos, tan, asin, acos, atan, sqrt, abs, ln, log and exp.
• Lathe cycle time estimator — Rough runtime for stock and finished OD/ID, drilling, threads, grooves, setup and insert changes.

Our calculators use independently implemented formulas. Cutting speed, chip load, force coefficients and controlled limit sizes need an appropriate manufacturer or standards source. The reference library explains where to obtain those values.

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