Stripped screw removal

SuperCub

SuperCub

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I recently bought a BRNO with a Leupold in a set of Talley mounts on it. I went to swap out the scope for another and found the allen type screws on the mounts to be EXCEDINGLY TIGHT :rolleyes:

I was able to get all screws loose except the last one, which of course, stripped at the head. :mad:

Question ...... Is it possible to have this screw removed without drilling and re-tapping? I would like to replace all the screws with the factory originals.


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Get yourself an "easy-out" from crappy tire. It is made to remove stripped screws. Spray threads with WD-40 and let work for several hours. Screw should come out without a problem.
 
If it comes to it, the screw head can be drilled away. Not the screw, just the head. The base can then be popped off, and the stump of the screw turned out.
In an extreme situation, the screw can be drilled out, without damaging the receiver threads. This does take careful work.
Another option is to cut away the base, although that is getting desperate.
Is it a blind or through hole?
 
tiriaq is right on the money. You don't say, but are there any traces of thread fastener on the screws you've removed? After removeing the head of the screw with a drill and takeing off the base, take a nail and file the end flat, and while holding it wit a pair of pliers to the top of the screw, apply some flame with a butane torch until the end of the nail touching the screw turns red. Ther will be enough heat transferred to the screw to soften the fastening compound and the stub will turn out easily with the already heated plyers. bearhunter
 
tiriaq said:
If it comes to it, the screw head can be drilled away. Not the screw, just the head. The base can then be popped off, and the stump of the screw turned out.
In an extreme situation, the screw can be drilled out, without damaging the receiver threads. This does take careful work.
Another option is to cut away the base, although that is getting desperate.
Is it a blind or through hole?
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I don't want to cut the base off the scope. Those puppys are expensive and it is working just fine as is. I got a quote of $169 for new ones. :eek:

It is a blind hole.

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Does the base dovetail onto the receiver? Does the screw thread into the receiver, or does it it jam against the receiver. I've never seen a Talley/Brno base. If the base dovetails on, and then the screw threads into the receiver, that will complicate things.
Usually, with a conventional base, once the screw is decapitated, the base will pop off, and the stump can be turned out, with application of heat, as bearhunter has suggested, if necessary. Removing the head releases torque.
 
If it is just the hex where you put the allen key in that is stripped, try using a flat punch to tap the metal back down and reform the hex. You shock the screw at the same time.

One of those hand impact drivers work really well here in getting the screw to let loose. You put the driver in the screw head, torque it in the direction you want to go and hit it with a hammer. It pushes down and turns. One of two things will happen, either the screw comes out :D or the head snaps off. :(

Bearhunter has a great idea with the transfer of heat onto the screw. That will help greatly with removing it.

I'm not a big fan of the grind and drill methods. Only when there is nothing left of the head to work with will I try to seperate the head from the shank.

Good luck.
 
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tiriaq said:
Does the base dovetail onto the receiver? Does the screw thread into the receiver, or does it it jam against the receiver. I've never seen a Talley/Brno base.
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The levers tighten a clamp into a dovetail in the reciever. The top of the reciever is sort of like a dbl flattop w/dovetail, the rear ring having a recoil lug. There are three screws on each ring, one on top and two behind the levers. The screws just goes from one side of the split ring to the other, holding the scope.

Failing the "easy out" suggestion, I'm pretty sure that your suggestion would work to remove the screw head. With the other two screws removed, it should pop off.

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CT, Sears etc sell a tool which is not an old school 'Easy Out', but a newer type. A traditional easy out requires partial drilling, and has helical threads.

It looks like a screwdriver bit, and usually comes in a pack of 2, giving you 4 sizes total.

When you press the bit into the screw head and turn counter-clockwise, 2 cutting edges bite the metal and remove the screw.

If it's that tight, I'd give it a shot of penetrating oil first, and maybe a couple of taps with a mallet. If that doesn't work, it's drillin' time...
 
if there's any thread left above the sirface, we used to dremel a slot in the core and use a blade screw driver to get it out- other than that, drill press and smaller size drill and drill and tap
 
It sounds like youhave the warne rings and that one of the screw hex heads is damaged, failing all of the above, if you can get at the reverse side of the ring ( I am assuming that this is not a screw that enters into the receiver ) take a smaller hard bit and try to drill out the screw from the reverse side. If you haver lubed it, heated it etc, and work very carefully with a press or mill, you will find that once the bit grabs a bit into the screw shank -- it will back out from the "front" . You can do the same with a left hand bit from the top side, but I find that the pressure you apply with the drill works best from the back side. I have saved more then a few bases / rings this way. But youhave to get at it fromthe bottom of the screw.
 
farshot said:
It sounds like you have the warne rings
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I think you are right about the rings being from Warne. They are an older style with one screw on the top instead onf the current 2 screw set-up.

I am going to wait till after hunting season before tackling this problem as the rifle is tuned and ready to go as is.


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if it's a blind tapped hole you may be bottomed out or you might be into incomplete threads and it is like a taper and galling occured. try getting the next key size up annd taper hex to tight fit, install in 1/4" drive socket and while applying steady down pressure and CCW torque give sharpe downward hammer blows. this duplicates the mpact driver concept most impact drivers require too many drive reducers to be effective and if your careful and get a good taper fit it may give you enough power to remove screw.
This problem can be avoided by placing the screw firmly in the base and counting the number of exposed threads then taking that screw and by counting the number of revolutions in or out of all holes is greater than the exposed # of threads. Generally this works if the mount and screws are quality products. Also buy name brand allen wrenches to start with and be sure the screw is not metric amd your using fractional with small hexs close is not good enough. Remember what you have tied up in the gun+ bases spend the few extra dollars for the tools, I actually find the screw drive style from bondus or allen better because of better feel than the L style any good machine tool supply co. can get you sets or individuals same thing for torx drivers...
 
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If you plan on drilling and using an extractor

Ian Robertson said:
Take it to a pro, it will cost less.
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I agree, unless you really know what you are doing.

I have removed too many broken extractors when customers decided to "do it themselves", the drill has wandered of the center of the screw into the surrounding metal and threads, then they try and use one of those cheap extractors only to have it break.

The job ends up costing three times what it would have cost if they had brought it in at first.

I would try the other options listed above before drilling.
 
First thing I would try is to see if I could jam a size larger allen or torx key into whats left of the hole , to get a grip on it. Between the inch and metric sizes, there are a lot that are close but too small or too big. Sometimes a gentle whack with a hammer, to get the driver to fit is in order. Of course, you want the work secured in a padded vise when you are doing this. You want to have a solid grip on the tool you are trying to drive in, too.

Is the hole a near match for an easy out? I have had best luck with the square shank ones, if just the tip is going to be used. The spiral ones need a hole that goes a fair way into the shank, and usually they are too large for the small screws.

Next is to use a dental burr in a Dremel type tool to carve the head out to be a slot head instead of a hex key socket. Take your time, and be careful, and you can usually crank the screw out with a decent screwdriver. You do want the driver to be as near the width of the head as possible, and as thick as the slot, if you can.

Failing that, the next step would carving or drilling the head off, trying not to drill any deeper than you must. Object is to leave as much stub as you can, if it is required to be able to grab with a small pair of pliers.

Usually, by this point, there is little tension left on the threaded shank that is left, and it will spin out OK.
If not, try carving a slot that you can stick a small flat screwdriver into (CTire has a miniature tool kit that works OK for this stuff. Goes on sale for about $10, has some watchmaker type screwdrivers and small pliers) and putting a little torque on it with a screwdriver.

Drilling down the shank of the thread is about the last option. It can be a right SOB to get the drill to start on center. Dental burrs again, or Dremel bits. Carbide is really nice to have. I like to spot the top of the shank with a ball ended burr, then start drilling with as small a drill as I think will suit. I have, on occasion, made my own easy outs, smaller than were available from the suppliers, by grinding the shanks of broken High Speed Steel cutting tools. Just a tapered square or rectangle cross section that can be tapped into the hole and twisted.

I deal with small, hard, broken screws in very expensive airplane parts almost daily. Escalation of force is key. Use the least that will get the job done. If you do not have the tools or confidence with them to do the job, stop early, and get thee to the pro.

If all else fails, you may have to resort to upsizing the hole, and tapping to a new size, or installing a helicoil, if you have the tools to do so (special tap, insertion tool), or you have a nice guy with a TIG welder fill the hole and you start over with some machining, polishing, and refinishing the mounts. (Uhhgggg!)

Cheers
Trev
 
Lee Valley sells a product called "screw grab" or something like that it is in a small plastic bottle and is a liquid with some grit (lapping compound?) in it.
It increases the friction between the screw head and the tool and I've found it works well for damaged heads or in situations where you think you might dammage the head.
I like the epoxy idea too.
Good luck!
 
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