Removing a rounded out allen head

[Walt]

Well I have rounded out the head on a Allen screw. No bite left and of course it's counter sunk and there is also a dose of Loc tite on the threads. It's small, 3mm Allen, head of screw is 6mm in diameter. It's in a scope mount on one side of the ring. Four Allen's total holding the ring in place. It's mounted on the rifle. Anybody have any tricks to get this out or is it just hacksaw time for the bracket?
W

[SDale]

Easily Done! Get a drill bit that fits inside the head and using plenty of oil, drill it through. Next (while the screw is still warm), use an E-Z Out (screw/bolt extractor) to extract the screw! TADAAAAA! All done!

If it's still tight and doesn't want to come loose, use a small pen torch to heat the piece up and soften the Loc-Tite.

E-Z Outs look similar to Taps, but have Looong helical left handed flutes that bite into the drilled out screw when "loosened" . They can be had from Sears, Home Depot, Lowes etc. for a small price.

[Machinist]

Walt:
There are four basic ways to remove that recalcitrant socket head cap screw (SHCS). However, I don't know what power tools you have available so I don't which of the 4 ways to suggest. Also, I assume you want to  avoid damaging the scope or mount so first dismount the scope from the rifle.
To save myself what could amount to an hour of typing I'll PM you.

Mike (Machinist)

[Crzyfrlss1]

I've been seeing this kind of problem pop up quite a bit lately.

Sounds like the problem stems from dissimilar metals (steel mated to aluminum).

The solution I think would be to apply a dab of never-seize to the threads of the allen bolts to help prevent this from happening in the first place.


As for removing the stripped bolt, I agree a drill and screw extractor is the way to go.
This is the kind I use for that purpose.

had the side of a cap head bolt snap off on a scope mount once, had to do the easy out job on it, and then had to try and find a similar bolt with the same diameter head size, but ended up having to enlarge all the holes for standard off the shelf replacements

word of warning most Allen head bolts are destroyed by cheap Allen keys, good quality Allen keys (often a hardened tip attached to a softer handle) will take daily hard use for years without the corners of the head rounding, if you notice the corners being rounded on either the key or bolt bin it, if you cannot bin it, shock the bolts using a suitable hammer and punch (of course impact driver where possible) then grind the Allen key down past the wear and keep the grind as sharp and square as possible, a little super glue in the socket around the Allen key and allowed to set can help take up some of the wear on the head or socket

if like on a typical set of rings there are 4 bolts and there is one that will not budge, quite often the last one tighten down the other 3 (but not fully) and try again

if you can use an impact driver without the danger of hurting the part, i sometimes sacrifice a Phillips head bit, place just the bit over the offending bolt and give it a few taps of the hammer, this will shock the bolt and cut a cross in the head of the bolt, then fit the Phillips head in the impact driver, pre load the impact driver a bit this way you can make sure it will turn the correct direction when hit and reduce how much the head turns and so damage your new cross marking less

dot punching the head of the bolt just in from the flats can help if it is not fully rounded

a good set of Allen keys will save so much grief, no matter where i find them in work, i take them and throw them in the bin, one set can cause so much hassle, oh and as for finding imperial keys where there are no imperial bolts, don't get me started

hope someone finds something useful in that

fin

[Machinist]

This problem popping up lately may be due to some misguided advice regarding the use of "Loctite" on scope clamp screws.
The design of the clamp allowing some built in "spring" makes it act much like a lock washer under the head of the screw - No Loctite Needed.

An ol' boy once said: Loctite has its place - but not every place.

[fnash]

I was going to say you don't need Loctite on the clamp screws. When the clamps are set around to scope tube they fit so snug that even when loosening the screws at times you still can't turn the scope. Have to open the clamp by prying with a flat screwdriver. Therefore in the first place the screws really do not need to be wrenched down. Just hand tight as much as the wrench will allow without putting leverage on it with a small pipe or something like that.... but as said cheap wrenches are killers too..... FN

[Walt]

Well I talked with Mike and I would like to thank him and all the rest that have chimed in. Like I said my problem is on the small side with not much room to work and my machine tool department is a bench top drill press, lacking to say the least. Anyway I am going with Mike's idea to JB weld a Allen wrench into the stripped out head and there you go. Again thank's for all the suggestions.
W

[paul]

Sometimes this will work,on any screw or socket head,unless you rounded it out beyond help. Take your bit or allen key and dip end in 0000valve grinding compound,the compound will grip with its fine gritty substance and will remove srew or capscrew unless it was  over enlarged.

Always try to use left handed drill bits, the heat will soften loctite and sometimes will unsrew the screw or caphead  right on out.

[howie1a]

How about heating a allen wrench and putting the hot allen wrench maybe that will be enough to soften the locktite , one other thing I would try before going way out is to take a old allen wrench the next size bigger and taper the sides so you have to tap it in to the socket kind of like a allen eazy out.