So apparently Stanley uses plastic gauges. How can I get this unthreaded from the manifold?
The screw in it surprisingly holds pressure… haven't filled it until it turns off so not sure if it can hold 150psi but it held about 60psi apparently fine.
seems like an accident waiting to happen though so I'd rather remove the broken threads and buy a new steel gauge.

Any ideas?

Get you a cheap set of EZ outs. Find the one that fits, tap it in then back it out.

If you heat a screwdriver you will loose the temper in the end and it will be useless afterwards

https://www.harborfreight.com/screw-extractor-and-left-hand-drill-bit-combo-set-10-piece-63987.html?ccdenc=eyJjb2RlIjoiNTY3NTIyMDQiLCJza3UiOiI2Mzk4NyIsImlzIjoiOS43NCJ9&utm_source=google&utm_medium=cpc&utm_campaign=12126402660&campaignid=12126402660&utm_content=150898465887&adsetid=150898465887&product=63987&store=3087&gad_source=1&gclid=CjwKCAiAnL-sBhBnEiwAJRGigr8rf4HNhSBgp4B50_kJk9pSuse1-1hyBeJ6odkTpBshEg_exDI3DRoCKGUQAvD_BwE

Those never worked great for me anytime i used them. Never end up biting like they advertised. As for losing its temper, you are not heating up the outer ring, just sinking the screwdriver into the plastic only. The plastic will eat the heat fast. You will not be heating the ring around it high enough even if you did quickly touch it to mess with its temper.

Edit: nvm reread post, your mean the screwdriver temper. Yeah, use a junker screwdriver like a 6pack one from harbor freight for a few bucks kind lol you are lucky if that cheap chinese steel was even tempered to begin with. They give these sets away for free all the time too.

EZ out might be your best bet. The plastic already has a hole to bite into, and it shouldn't be all that tight.

Who here has ever had success with an easy out?

My money is on screw driver idea.

I use them regularly with good results.

Trick is to know when/how to use them. Plastic inside metal is a perfect use. Should be zero corrosion.

Broken bolt is old cast iron, not the right application. In that case, heat and penetrating oil will be a better option.