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Posted: 8/4/2022 8:19:47 AM EDT
So bad luck struck yesterday when attempting to drill a detent hole in one of my lowers. I attempted to drill it out but stopped as I figured I would do more damage. Anyone have any ideas as to what I should/can do now?

William in Cocoa
Link Posted: 8/4/2022 9:01:35 AM EDT
[#1]
I've never had to do anything like this before so I'm just going on experience from other things.

Put a drop of the thinnest oil you can find in the hole then blow it deeper with compressed air.

Then use a rubber mallet and tap the receiver on the sides a couple times to hopefully loosen up the broken bit and finally tap the reciever down on a piece of wood covered with cloth to try to make the drill bit fall out.

Good Luck
Link Posted: 8/9/2022 10:53:31 AM EDT
[#2]
Detent hole in an Colt Sporter lower?
Link Posted: 8/9/2022 7:30:31 PM EDT
[#3]
Maybe something like this to reverse it a bit to loosen it
You might have to modify it because the drill bit only has two flutes.
Link Posted: 8/10/2022 8:20:33 PM EDT
[#4]
ive been reserving comment to keep from appearing like an ass......but.....I would assume 80% lower you are making?. .
Could you drill the shit out of it then sleeve it securing the sleeve with epoxy, or tap it then thread a sleeve?

Or maybe a much shorter spring?????

I'm intetested to hear how you fixed this this. Sounds like something I could find myself facing one day as I seem to handle drill bits as consumables like dirty diapers.... I destroy them.
Link Posted: 8/12/2022 9:08:17 PM EDT
[#5]
How much bit is exposed?

Enough to nibble down the edge of a steel washer and tack weld them together?
Link Posted: 8/13/2022 11:54:47 AM EDT
[#6]
Sorry everyone I didn’t realize there were so many replies. The lower is an older Colt 6721, I attempted to drill out the bit and after about 10 seconds I realized that wasn’t working so I stopped any further attempts. I tried heating the lower and tapping it with a mallet, and banging it onto a wood block, but nothing has worked. I don’t have an air compressor, nor do I think that’d work because I attempted drilling the bit out with a smaller bit. As is it just has the screw on take sown pin so I can at least still shoot it. I’m located in Cocoa so I can travel a bit if someone has any ideas they’d like to try.

William
Link Posted: 8/13/2022 9:18:59 PM EDT
[#7]
Well shit that sounds 10 times worst than I though with a real lower. I thought about the heat but dismissed it based on size and materials. Im stumped. What about drilling a divot into the bit and trying a screw extractor by hand with pressure and maybe some PB penetrating oil.
Link Posted: 8/13/2022 9:24:42 PM EDT
[#8]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Sorry everyone I didn’t realize there were so many replies. The lower is an older Colt 6721, I attempted to drill out the bit and after about 10 seconds I realized that wasn’t working so I stopped any further attempts. I tried heating the lower and tapping it with a mallet, and banging it onto a wood block, but nothing has worked. I don’t have an air compressor, nor do I think that’d work because I attempted drilling the bit out with a smaller bit. As is it just has the screw on take sown pin so I can at least still shoot it. I’m located in Cocoa so I can travel a bit if someone has any ideas they’d like to try.

William
View Quote

Do you have a strong magnet handy?
Link Posted: 8/14/2022 9:48:26 AM EDT
[#9]
I do not, any idea where to get one? I used to know a guy that had some crazy powerful ones but lost touch with him.
Link Posted: 8/14/2022 10:02:58 AM EDT
[#10]
Link Posted: 8/14/2022 2:59:47 PM EDT
[#11]
So, you confirmed what I though you were doing.  

If I were in your boat, I'd see myself with a few options:

1. EDM to remove broken bit.

2. Put original pivot pin back in.

3. Drill oversize and press in a bushing.

Without pics I cannot see how bad your situation is, but since the bit is so much harder than the surrounding material, I don't see much success in drilling or breaking it out without blowing the hole.  How deep were you able to drill before the bit broke?
Link Posted: 8/14/2022 7:11:23 PM EDT
[#12]
Unfortunately I was literally about to pull it out and call it done when it broke?? I wouldn’t have any idea how to EDM anything, I know what that stands for but have no access to one. I’m going to try the penetrating oil and magnet, along with some heat and hope for the best unless something better comes along.

William
Link Posted: 8/14/2022 8:06:10 PM EDT
[#13]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Unfortunately I was literally about to pull it out and call it done when it broke?? I wouldn’t have any idea how to EDM anything, I know what that stands for but have no access to one. I’m going to try the penetrating oil and magnet, along with some heat and hope for the best unless something better comes along.

William
View Quote


Try putting it in the freezer overnite?
Link Posted: 8/14/2022 11:18:48 PM EDT
[#14]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Unfortunately I was literally about to pull it out and call it done when it broke?? I wouldn’t have any idea how to EDM anything, I know what that stands for but have no access to one. I’m going to try the penetrating oil and magnet, along with some heat and hope for the best unless something better comes along.

William
View Quote

A little vibration or tapping in conjunction with the magnet may give you a fighting chance at it. Let us know how it goes.
Link Posted: 8/15/2022 10:17:48 PM EDT
[#15]
How to remove a broken tap / drill bit the easy way



Removing Broken Tap by Oxidizing in Aluminum Sulfate Solution

Link Posted: 8/16/2022 5:20:31 PM EDT
[#16]
Link Posted: 8/16/2022 5:22:49 PM EDT
[#17]
I wonder what that’d do to the black anodizing though ??
Link Posted: 8/16/2022 7:45:48 PM EDT
[#18]
Had same thing happen, tap broke off in the detent hole (was trying to thread it to give some tension adjustment to the detent itself).

For $20 you can get a KNS push-pin cotter pin/clevis pin type thing, works great.

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