Broken scope mount screw

jbear29 · May 13, 2019

I know this is the S&W forum but I am sure someone here can help my none the less.
My zero kept shifting on my Savage .223. I decided to take off the scope to see what was wrong and found both rear mount screws broken off. I got out one of the screws out but the other is flush with the rifle base. I know it has blue loctite but I can heat it to melt it away. What do I do to get the screw out??
I would normally think drill it and use an ez out screw extractor but the diameter of the screw is so small I don't think it will drill. I know someone has had this problem before. Please advise what I need to do to get the screw out without gun damage.

Thanks

Fishinfool · May 13, 2019

I am no gunsmith, but years ago, I was in a similar situation, and the gunsmith ended up drilling out the screw, and tapped the hole for a larger size screw. Blue LocTite does not need heat to loosen it like the Red formula does.

My real question is why both rear base screws broke. Where they over tightened?. My concern would be a possible misalignment between the mounting bases causing stress on the rear mounting screws. Just a thought anyway.

Larry

67tempest · May 13, 2019

The correct way to do this is to first set the rifle up in a mill. Index off the screw and machine the top off the broken screw flat using a properly sized center cutting end mill. Spot the hole and then drill out the screw using a left handed drill bit. More often than not the broken screw will unscrew itself using a left handed drill bit. You will regret it if you try to do it without a mill.

Skeetr57 · May 13, 2019

What I have one in the past is take the gun to a friend who is a professional welder and have him put a few drops of steel on top of the broken screw with his MIG welder, then use a pair of vise-grips to back the broken screw out. This same procedure is used to remove broken taps. With a sharp electrode and a steady hand, the bluing is not harmed.

WR Moore · May 13, 2019

jbear29 said:
but the other is flush with the rifle base. I know it has blue loctite but I can heat it to melt it away. What do I do to get the screw out??

What do you mean by "flush with the rifle base"? If the head broke off and there is a stub sticking up above the receiver you have multiple ways to proceed.

Heat applied to the screw stub will help with the Loc-Tite. Then vise grips applied to the stub may let you back the screw out.

If you have standard 6-48 mounting screws, you can in fact use an easy out. But, given the small diameter of the tool heat is indicated to help limit the torque needed to remove the screw given the thread locker.

The gent who suggests that use of a milling machine to cope with any drilling is correct. The machinist can align with the stub and either drill for the easy out or possibly drill the bulk of the screw out and just remove the remains with a tap. Or, go to an 8-40 screw for that hole.

On larger diameter fasteners I've welded headed bolts to stubs to remove them. The welding heat expands the stub and after, cooling they sometimes screwed out by hand.

steelslaver · May 13, 2019

Probably a size 6 screw. For a size 6 you use a #35 bit to drill for tapping. That is about 1/8". If the top is broke of smooth you might try using a real fine punch and holding it on one edge at a angle and tapping it with a small hammer so that the taps turn the screw a bit. Wouldn't hurt to have the barrel warmed up a bit. I have got lot of broke screws to turn out that way.

If that don't work do like 67 tempest suggested. I would be really amazed if some one could put just a spot on it even with a .023 mig. Maybe if you taped a small piece of mettal with a tiny hole in it centered over the screw you could tack the metal to the screw.

chief38 · May 13, 2019

Heat the stud up with a hairdryer then mask off the area with some card stock and tape so if you should slip you will minimize the chance of scratching the rifle. Use a LEFT HANDED Drill Bit and hope that pulls it out.

PS: I never use Locktite on firearms.

kenjen · May 13, 2019

A soldering iron will put heat where you need it to melt the loctite. And a rotory tool can cut a slot for a screw driver. Or center bunch and drill a hole and use a easyout

growr · May 13, 2019

Great suggestions by all...how did this finally turn out?

Randy

spdguns · May 13, 2019

I use a drill press with a cross-slide vise. Use a center drill to locate the center of the broken screw and start the hole. Then switch to the smallest left hand drill bit you can get away with. GO SLOW with penetrating oil. Then I use a pencil tip soldering iron to get the screw as hot as I can. I then gradually use larger left hand drill bits DRY until i can get a small screw extractor in it. Sometimes I get lucky and the screw backs out while drilling.

67tempest · May 14, 2019

steelslaver said:
If that don't work do like 67 tempest suggested. I would be really amazed if some one could put just a spot on it even with a .023 mig. Maybe if you taped a small piece of mettal with a tiny hole in it centered over the screw you could tack the metal to the screw.

I agree that it would seem impossible to use a MIG to weld to the top of so small a screw. Somebody really good with a TIG might be able to do it but if you screw up you will end up welding the screw to the top of the receiver.

s&wchad · May 14, 2019

I’ve had success cutting a slot in a broken screw with a tiny ball cutter and manually backing it out with a drill press.

After cutting the slot, secure the part in a machining vice and chuck an appropriate screw driver bit in the drill press. Lower the press head and align the bit with the slot. Use the feed lever to provide downward pressure and turn the chuck head by hand to back out the screw.

Broken scope mount screw

jbear29

Fishinfool

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67tempest

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Skeetr57

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WR Moore

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steelslaver

US Veteran

chief38

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kenjen

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growr

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spdguns

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67tempest

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s&wchad

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