Home Forums Hunting & Shooting Gunsmithing Screwed the pooch trying to unscrew...

Yep. I effed up. Model 100 Win scope mount screws. They were being ornery and not budging after 50 years. Shoulda heated them or Kroil or both. I was impatient and gave her the beans. Snapped the head off. The stud of the back screw is sheared off about a half mm above the receiver. Not enough purchase to get ahold of. Drilling and easy out might be an option, but I don't have a drill press and I'm not sure they make easy outs that small.

Anybody have a remedy? Thanks.

I had same thing happen, drill bit just smaller than screw size, carefully with drill bit moving very slow drill screw, takes a while with a lot of shavings but was the only way i could get it out, once you get to bottom of screw it relieves pressure and screw will turn out with just a bit of downward pressure and a twist of finger

if you have a buddy with a mill, EDM, or a Forester drill jig it's a easy fix, i removed hundreds of these, its a piece of cake

The thread probably runs into the action, small drill down the middle, soldering iron for a bit, then use a slightly bigger bit, it should bite and drive the screw into the bolt raceway

Rule #1: Don't make a bad situation worse.

Rule #2: Use the right tools for the job.

Find a 'smith or a real machinist with a mill and have them do it. That gets you around Rule #1 and takes care of Rule #2.

Rule #3: Pass your money over gladly. And appreciate how much he actually saved you in the long run.

Good shootin'. -Al

By your own admission you do not have a drill press so I am assuming you do not have a milling machine or the forester jig someone else mentioned. Take it to someone who does and knows what they are doing. IF you manage to drill it straight and true with a Dewalt or Black and Decker by hand and not damage the hole or threads, go buy a lottery ticket that day, cuz you are lucky.

For comparison:

-Average quill wander of a home or light shop drill press is around 1/16" (.065"). They can be as bad as .125" (1/8").

-External dimension of a 6-48 screw is .135"

So....a home/light shop drill press has an error (.065") of almost half the diameter of the fastener (.135") you want to remove!

Now add in the deflection of a drill bit...even a quality one. And what happens when a 135 degree drill bit point hits a screw head with half of the screw slot snapped off?

The spindle runout on a 'middle of the road' mill will be less than .0005 (5 ten thousandths or 1/2 of a thousandth)....often much less. Now put a correctly dimensioned, flat end mill in that with minimal deflection.

Not hard to connect those dots!

Good shootin' -Al

Take it to a real gunsmith.

I'd take it to a gunsmith and let him mess with it if you don't have the where with all to do it yourself. A carbide end mill ran fast, smaller than the screw will do it but you have to go slow and not push it.

Just for sake of discussion, here's one from a couple days ago. I did this one for a good pal several years ago. He wants to do his own maintaining on it and wanted advice on how much to 'torque' the action screws down. I showed him how to get the barrelled action in and out, seat the recoil lug and tighten the action screws on my pillar bedding job with an Allen wrench. Educated him on the fallacy of torquing action screws on a well done, stress free pillar bedding job. Or so I though. Bada bing, bada boom. Done, right?

He calls yesterday and said he bought a good torque wrench. Problem was that he bought a lbs/ft. one rather than an inch/lb. wrench. At 50 lbs./ft., the Allen recess in the front action screw decided it had enough and rolled over.

So there I am yesterday morning......

When 6-48 screw holes are no good, I drill and tap them for 8-40.

So far in 56 years of amateur gunsmithing, I have only had to do that once, on a stripped out Ruger 10/22 that was $30 at a pawn shop.

But I do know there are guys on Snipers Hide that build rifles starting out with 8-40 scope base screws.

Sage advice right there.

Not a gunsmith.

But in cases like this I use a drill close to the od
of the threaded part of the bolt.

The socket guides the drill.
When you get to the bottom of the head, it pops off.

No damage to threads or whatever it was holding.

I guess I should be thankful for the years spent in a machine/mechanic shop with my uncle. Then 25yrs in aviation R&D fixing other people's mistakes.

I removed a broken 10-32 tap out of a blind hole and then drilled and removed 3 broken corroded 10 -32 stainless screws this morning. I use a 600 or 900 rpm hand drill, some Boelube and a standard drill guide.

I should call my uncle and thank him.

Exactly this. Looks like Al did a little damage to the floor plate. Why the fu is he using such a big end mill? Should have taken it to a gunsmith..

The "damage" is part of modifying the floor plate to eliminate the small tapered seat screws. After enlarging the opening and making a flat seat, a button head screw is used. You get roughly 50% more contact and the flat-to-flat seats better than the tapered contact.

I Agree!

Same!

Glad to hear it was intentional.

Yeah...I probably should have noted that in the original post! -Al