Why grind a thread instead of cutting it?

Grinding works after hardening and reaches higher accuracy, so the thread stays exact on hard parts such as gauges and lead screws.

Can internal threads be ground?

Yes, on internal thread grinders, but only above a minimum size, usually around M10–M12 depending on the machine.

Is thread grinding expensive?

It costs more than cutting or rolling, so it is used only where accuracy or hardness demands it.

Thread grinding job work: accuracy, uses, process

Thread grinding forms a screw thread with a shaped grinding wheel instead of a cutting tool. It works on hardened steel and holds very fine accuracy on pitch, angle and form. It is used for thread gauges, taps, lead screws, ball screw parts, worms and precision studs that must stay accurate after hardening.

Quick facts

Works on: Hardened and soft steels, tool steels
Wheel type: Single-rib or multi-rib form wheel
Pitch accuracy: A few microns over a short length
Thread types: Metric, unified, trapezoidal, Acme, worms, special forms
Usually done: After hardening
Usually priced: Per piece, by size and length

When ground threads are needed

Thread plug and ring gauges
Taps and thread-rolling dies
Precision lead screws and ball screw shafts
Worms for quiet, accurate gearboxes
Hardened parts where cut threads would distort

Ground, cut or rolled threads?

	Ground	Cut (turned/milled)	Rolled
Accuracy	Highest	Good	Good
On hardened steel	Yes	Hard	No
Speed	Slow	Medium	Fastest
Typical use	Gauges, lead screws	General parts	Fasteners in volume

What to send

Drawing with thread form, pitch, class and length
Material and hardness
Datum centres or journals to grind from
Inspection needed (gauge, pitch report)
Quantity

Need thread grinding done?

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Related job work

Machines

Materials

Questions

Why grind a thread instead of cutting it?: Grinding works after hardening and reaches higher accuracy, so the thread stays exact on hard parts such as gauges and lead screws.
Can internal threads be ground?: Yes, on internal thread grinders, but only above a minimum size, usually around M10–M12 depending on the machine.
Is thread grinding expensive?: It costs more than cutting or rolling, so it is used only where accuracy or hardness demands it.

The figures on this page are typical values for guidance, written by Diemeco from standard engineering practice. They are not a specification: confirm grades and properties with the relevant standard or the supplier's mill test certificate, and tolerances with your workshop. Last checked 23 October 2026.