Spur Gear Geometry Lab | Patrick Doring

Gear train

1–64 gears. Each added gear meshes with an earlier gear; all shafts are parallel in one plane.

Meshes with

Shared tooth system

Display units

Module and pressure angle are shared so the teeth mesh. Placement is the line-of-centres angle, measured clockwise from the right. Root radius = module × fillet factor.

CNC cutter & limits

Require CNC checks for SVG export

Actual tooth-root radius mm

Fit may increase root radius Fit may reduce tooth height

Find a proposed fit without changing cutter limits, tooth counts, bores or stock.

Motion & preview

Driver speed · RPM

Playback multiplier

Pitch circles Gear labels Shaft dimensions Cutter markers

Driver 0.0°

Driver phase · one revolution

Geometry & mesh checks

Unshifted external involutes with circular root fillets. Motion uses ideal tooth ratios; backlash is clearance, not a dynamic impact model. Each mesh is sampled over one complete tooth period.

Gear	Teeth	Pitch Ø	Outside Ø	Root Ø	Bore Ø	Stock	Speed / driver	Shaft X / Y

Mesh	Shaft spacing	Contact ratio

CNC profile checks

Gear	Root radius	Tip width	Tooth space	Bore wall	Cutter access

Sampled planar cutter checks use the actual exported profile and the endmill radius plus fitting allowance. They do not establish continuous toolpaths, holder clearance, workholding, strength, or feeds and speeds. Flute length 0 means unspecified. Stock thickness is a dimension for extrusion, not part of the 2D sketch.

SVGs contain the finished outline and optional bore, with no cutter compensation or preview overlays. Fusion uses insertion scale 1.0 (96 SVG units per inch). Gear geometry reference: KHK.