Glow plug thread info.

[Mike Winston]

Hopefully a simple question: what is the thread angle on the 1/4” x 32 a glow plug?
Cheers in advance.

Mike

 

[Woodster]

Looks like a 55 degree thread after a quick Google
https://www.motalia.com/Html/Charts/me_chart.html

 

[Mike Winston]

Cheers Woodster, that’s a help, thanks.

 

[Jasonb]

No it is 60 degrees. The thread used is 1/4 x 32 UNEF not model Engineers series.

 

[Mike Winston]

Thanks Jason. I’m new to this IC building so I’ll probably have more questions as time goes on - grateful for your advice.

 

[tornitore45]

Just because is a "Model" plug does not mean it uses a model thread.
It never even crossed my mind that it could be other than a unified thread.
I tapped a couple dozen 60* and all they fit right.

 

[bluejets]

News to me as well as I have used standard 1/4 32 me in the past without any issue.

Confirmed in this video on a recoil kit.
If one looks at the lower part of the kit case one can see the reference to UNEF 1/4 32