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Joined:
Jan 2026
Posts:
1
EE: 0% (0)
NE, USA
Posted: 1/18/2026 1:17:25 PM EDT
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I installed a CMMG Zero-d gas block and lost the screw/detent/spring for the adjustments. Luckily, you can buy a replacement for dirt cheap. Unluckily, to re-install it, you have to remove the gas block. When I installed it, I used a dab of red loc-tite on the threads. After a bit of heating, the first screw came out without any issue. The second screw broke my bit off in the screw. Any advice for removing the screw? I tried supergluing the bit shank back on and pulling it out but that didn't work. The bit is also harder than the cobalt drill bits I have and my attempts to drill it are just skating off and damaging the screw. It broke off flush with the top of the screw, so I can't beat in a torx bit and try to remove the entire screw. At this point, I'm thinking my best option is grab a cut-off wheel and buy a replacement, but I'm looking for anything else to try first. |
Joined:
Nov 2022
Posts:
4069
EE: 100% (4)
SC, USA
| Nobody knows more about the thing than the company that makes it. Call them tomorrow and get their advice. They can probably point you to the exact tools and method of removal that you need. They know exactly what the bolts are made of, so they know how to remove them, and they can send you any additional products needed. |
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This won’t help you now, but you should never remove all tension from one screw prior to breaking the second one loose. The gas block is a stretched hoop. The screws pull the hoop out of round when tightened. The hoop is constantly trying to return to round, putting pressure on both screws. When you remove one screw, all that snap-back tension goes to screw number two, making it much more difficult to loosen than if some tension were still taken up by the other screw. Tony |
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Try freezing the barrel/GB overnight. Secure the barrel in a vise with the GB screws oriented at BDC, tap on the GB with a hammer. Many times the broken bit will drop out. Another option, in the event that that doesn't work, a carbide end mill will make short work of it if you have access to the tooling. As an extreme plan of action, a cut off wheel and a Dremel tool coupled with a steady hand will remove the GB. And, unfortunately, leave you ~$60 out of pocket. |
"All welchers should be removed from the EE".-Aimless
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Originally Posted By TonyRumore: This won’t help you now, but you should never remove all tension from one screw prior to breaking the second one loose. The gas block is a stretched hoop. The screws pull the hoop out of round when tightened. The hoop is constantly trying to return to round, putting pressure on both screws. When you remove one screw, all that snap-back tension goes to screw number two, making it much more difficult to loosen than if some tension were still taken up by the other screw. Tony This, 100%. ^^^^ |
"All welchers should be removed from the EE".-Aimless
Joined:
Jan 2026
Posts:
2
EE: 0% (0)
NE, USA
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Thanks for the advice. I tried freezing the upper overnight and hammering on it, but that didn't work. I had to stop by a new hardware store for work today and they had a Diablo multi-material carbide drill bit. Apparently its supposed to be used in hammer drills, but it worked fine in my cordless drill. With a bit of oil (but absolutely no chatter), it ate through the stuck bit and most of the screw. Now I just need to get an extractor the right size to get the screw out. |
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