12-05-2025, 05:44 PM
(11-05-2025, 12:08 AM)falcott Wrote: Do helicoils work for threads already tapped out to 5/16"? I've never used helicoils before.
For example, would these work?
https://nzsafetyblackwoods.co.nz/product...-20-457154
Sorry not to come back sooner, I have been away.
In theory, the answer should be no. However, over the last 30 years, I have probably fitted at least 100 1/4 bsw helicoils straight into 5/16 bsw sump holes.
To be absolutely certain that this is the case - I just went out into the workshop and fitted one into a bell housing stud hole of a crankcase I am working on. I can confirm the 1/4 bsw helicoil wound nicely into it and the 1/4 bsw sump bolt them wound into the newly fitted helicoil, as it should, using my finger and thumb.
I use 1/2 depth helicoils in this application.
If you wish to try this yourself, V-Coil thread inserts are reasonably priced, here at least.