Infinite Engineering · Thread mill calculator

Thread mill calculator

Tapped holes for wire thread inserts (EG / STI to DIN 8140) and standard ISO metric threads (DIN 13 / ISO 965). Gives the drill, the CAM thread table values, what the posted code should show, and the cutter offset to set on the machine.

Your cutter and thread

Thread type

Insert thread required

Pitch (thread and cutter)

Thread mill tip diameter, measured

Over the tooth tips. Any full-profile 60° cutter of this pitch will do.

Tolerance class of the tapped hole

Machine takes cutter offset D as

Result

Recommended drill

–

Drilled bore
Thread major diameter
Cutter at full depth
Tool centre path

Row to add to the CAM thread table

In OneCNC: Thread Mill Options, then “more…”. Add a new row; leave the standard M rows untouched.

What the posted code should show

Cutter offset D on the machine

DIN 8140-2 limits for this tapped hole

If you cannot add a row to the thread table

All insert threads, ready for the thread table

Major and minor are the values to type into the CAM row. Select a thread to load it above.

Thread	Major	Minor	Pitch	Drill	Bore max (5H)	Arc radius I

Standard ISO threads per DIN 13 / ISO 965-1: major = d, pitch diameter = d − 0.64952 P, minor = d − 1.08253 P, with 6H as the default class. Geometry per DIN 8140-2: the insert thread is the nominal thread enlarged by 1.299 × pitch, same 60° profile and pitch. Major = d + 1.29904 P, pitch diameter = d + 0.64952 P, minor = d + 0.21651 P. Minor tolerance is 5H from ISO 965-1; pitch diameter tolerance is calculated from the ISO 965-1 formula and may differ from the printed table by a few microns. Only an EG go/no-go gauge certifies the tapped hole to the standard, so check against the DIN sheet or your insert supplier's data where that matters.