Other Thread Forms
and Specifications

Shown below are some of the more regularly used thread forms which are gauged using our products, all available on short lead times. The tread proportions are shown for guidance and we should be consulted for detailed information.

Original Gauge and Calibration Solutions has a comprehensive library of thread gauge standards. We will be pleased to advise on the correct specification for your application.

Thread Gauges to Japanese (JIS) specification

The JIS system is rather different to BS and ANSI. Some of the main specifications are summarised here:

JIS-B-0251 Metric coarse pitch series
JIS-B-0252 Metric fine pitch series
JIS-B-0253 Pipe threads for pressure tight joints
JIS-B-0254 Pipe threads for non-pressure tight joints
JIS-B-0255 Unified threads fine pitch series

It should be noted that the gauging philosophy of BS, ANSI and JIS can be quite different so the required specification should always be clearly stated.

Multi-Start Gauges

Plug and ring gauges for testing multi-start threads, within the range of practicality, can be supplied.

Please submit details of your application to our technical department for evaluation.

Wire Insert Gauges

Screw plug gauges are available for testing pre-inserted tapped holes for helicoil inserts and wire inserts.

When ordering gauges for pre-insert threads, it is important to state the type of insert to be fitted i.e. Helicoil inserts to Armstrong data sheets, or wire inserts to British Standard specifications.

MJ thread: BS.A358:2000/ISO5855
Controlled root radius, for aerospace applications.
External threads are designated 4h/6h
Internal threads < Ø 5mm 4H/6H
> Ø 5mm 4H/5H

UNJ thread: BS.A346:2000
Controlled root radius, for aerospace applications.
External threads are designated 3A
Internal threads are designated 3B