Thread Repair Tools

Internal Thread Chasers

Start with the thread inside the hole and the room you have to reach it. A compact chaser and a double-ended chaser can serve different access needs even where their stated sizes overlap.

What to check before ordering

Compare the tool maker’s application, thread size and pitch with the equipment documentation. Read the working end and drive interface as separate dimensions. Lisle lists its limited-access and double-ended spark plug chasers under different model numbers. Check the exact model before comparing their reach.

Fit inside the opening

Compare the working thread with the equipment specification. An M18×1.5 sensor chaser and a limited-access M14×1.25 plug chaser serve different openings.

Tool clearance

Note the socket drive and body profile separately. The space for a socket or extension can decide between two compatible chasers.

Compare documented examples

Manufacturer references

Frequently asked questions

Does a double-ended chaser have two supported pitches?

Check the designation of each end in the exact product documentation. The overall tool length or socket size does not describe the threads.

What dimension should I look at for a recessed opening?

Compare the clearance around the opening and the maker’s tool dimensions. Thread fit and access are separate requirements.

Buying guides