I am attempting to remove the two pairs of OEM screws from each of the two scope base mount "filler plates" (on top rib) so as to first time mount Racknagel bases on a new Chapuis UGEX (9.3x74R). The screw head slots are each approximately 0.182 inches long by 0.025 inch blade thickness. I was using the hollow ground Wheeler engineering bit set and have a reasonably good blade fit (at least for the screw slot tops). However the existing screw slots were hourglass shaped when I got the rifle, warning signs suggesting that the screw heads were a bit soft when originally installed by the Chapuis technician. The screws are in there very tight somehow. I lightly hammer tapped (using plastic head) the wheeler bit snugly down into a screw head and found that the screw would not budge(turn) without risk of beginning to hour glass deform the slot on me. Does Chapuis glue them in or what? How do I get them out minimizing damage? Is a pinpoint blow torch required on the top-rib? Penetrating oil soak for two days? I would have thought that tapping the screw head would help break the thread binding... but no. Suggestions from those who have accomplished this task would be appreciated. I looked for a previous post on this subject unsuccessfully so sorry to bother you about this. Ken at KEBCO warned me the screws can be tough to remove. He was not kidding. You guys that got them out...how did you do it please? Thank you for any assistance.
PS: I was lottery drawn for a black bear hunt in October and was advised to get a scope on the rifle for good shot placement and quick follow-up shot. Planning to mount a Trijicon TR24-3 AccuPoint 1-4 x 24 Amber German #4 Crosshair if I can get the screws out.

Mine were pretty tight as well. I was able to remove them by hammering the screw driver into the screw slots. As you said, a bit of penetrating oil might help as well. Other than that, I don't know. That's what worked for me.

I mounted a Trijicon 1.25x4 on mine. Had one hell of a time getting the rifle to shoot to regulation with the scope mounted. It took 14 different loads before getting a combination that worked. Others here have had zero issue with their UGEX when mounting scopes so it will be a crap shoot at best. However, I do think it well worth the trouble once you get it figured out and you'll have no problems shooting past 100 yards with that set up. I took a Black Bear with mine in April at 116 yards using the 250gr CEB Non-Cons. Slammed him like he was run over by a freight train.

Good luck with it.

Mine were quite easy to remove, but Dale said earlier ones were tightened way too tight, so the factory must have started not making them so tight. Yes, they are soft screws which makes things worse. Oil won't help; they aren't rusted in place; and it's not the threads that are tight; a bit of heat might, but be VERY careful. Worst case, drill them out with a center drill. Sometimes a tight fitting screwdriver makes the heads expand. You can use a drill press and a high quality driver bit rather than a hand held screwdriver. good luck. I need a scope on mine to get my cheek up off the stock; I literally can't shoot it now due to the pain. Not recoil; upward smack of the comb due to the heel drop. As for a 9.3 on bear; I have killed one with a 9.3 double; dropped it in its tracks, which doesn't usually happen on bear. I gave it the other barrel just to make sure as I never fire only one shot from any DR. That evens out the bore wear and it is twice the fun.

Mine was one of the earlier ones that was a PITA to get them loose. I ruined several fitted Wheeler bits before I drilled the head off and then it was very easy to pull the blocks and with fingers remover the shanks of the screws.

You can try heating the screws with the tip of a soldering iron. That way is very difficult to damage anything.

quote:

dpcd
Oil won't help; they aren't rusted in place; and it's not the threads that are tight; a bit of heat might, but be VERY careful.

quote:

Originally posted by herrdoktor:
You can try heating the screws with the tip of a soldering iron. That way is very difficult to damage anything.

Gentlemen I think you have this backwards! Heating steel causes it to swell, cold cause it to shrink! Put the action in the dreezer for abot 20 minutes or obtain a small piece of dryice, and touch only the head of the screw for a minute,this will shrink the screw and it will turn out with a screw driver easily.

This a trick we used to keep the screws from backing out on magnum pistols. We tightened the screws as tight as we could, then put the pistol in the freezer for a few munites, and every screw would turn another half or full turn, and when the pistol returned to ambient temprature the screws were so tight they wouldn't back out under firing! To take them out you put them back in the freezer to shrink them again.

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Sorry if I'm stating the obvious BUT. Once you get the screws and fillers out, the bases for the rings may not fit into the recesses. I think they make the bases slightly large so they can be properly fitted.

Use a stone or a fine file to fit the scope base to the slot in rib. Don't modify the rifle.

I always used one of these for tough screws tap tap tap:
http://www.harborfreight.com/i...with-case-37530.html

My "dreezer" is way too small for my barrels to fit in to.

quote:

Gentlemen I think you have this backwards! Heating steel causes it to swell, cold cause it to shrink!

The idea of the heat is to get the loc-tite to release, as higher heat destroys it's holding power, and it DOES work. I've used a electric soldering gun to release loc-tite many times.

DM

They screws aren't loc tited in but if they were, yes, heat will turn loc tite to powder. . Don't forget that a little heat will also expand the rib block enough to help get the screw out, but he is right, the head will expand as well. I have removed many stuck screws and sometimes, especially with soft screws and narrow slots, drilling them out is the only way. Easier and you won't scratch your rifle with a slipped screwdriver either.

quote:

Originally posted by DM:

quote:

Gentlemen I think you have this backwards! Heating steel causes it to swell, cold cause it to shrink!

The idea of the heat is to get the loc-tite to release, as higher heat destroys it's holding power, and it DOES work. I've used a electric soldering gun to release loc-tite many times.

DM

If they are lock-tited you are right, but if they aren't, just tight, then cold is what you want.

quote:

Originally posted by dpcd:
They screws aren't loc tited in but if they were, yes, heat will turn loc tite to powder.
Don't forget that a little heat will also expand the rib block enough to help get the screw out, but he is right, the head will expand as well. .

You still have it backwards the word EXPAND means to get larger or swell. If the screw EXPANDS it will get tighter, and if both the screw and the block EXPAND or swell it will get even tighter still. When heated the steel EXPANDS NOT THE HOLES. When steel expands any hole drilled in them get smaller, and any heated screw in those holes get larger!

The use of an impact screwdriver is a little risky on a soldered rib, but on a small screw it might be all right. I have used impact screwdrivers for years on motorcycles in the pits while motocross racing and they seem like a very good idea at first blush, and you may get away with one, but I’ll just stick to the freezing of the screw on a soldered rib!

In any event it is your double rifle, and you may do as it suits you!

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I don't know how many frozen screws you have removed and won't guess. I know that heat works, (although I have not had to use it on double rifles) and your comments prove my premise; that the screws expand; yes, and they expand longitudinally too, thereby relieving the pressure on the underside of the head which is, after all, where they are tight. It isn't the head diameter interference that makes them stick in the hole. And heating a piece of steel as thin walled as a rib is, with a hole in it does not make the hole smaller. Actually, it doesn't matter how big the surrounding steel is; The hole will get bigger; that is how we shrink fit things. I know, it is counter intuitive but true. Be careful using heat on a DR, however.

Thank you gentlemen. I am attempting to obtain an impact screwdriver set from Sears ($25) or Harbor Freight ($7). The drill press idea has merit. However I already twisted/torque deformed the Wheeler flat head bit (about 20deg) by hand, so 1) I have to replace the bit, 2) I suspect the impact driver will simply torque twist deform it still further (causing it to "jump" out of the slot or deform the screw head/slot, or both, score the top rib and probably lacerate my radial artery...).
I might have more control with the drill press maintaining pressure downward against the screw head. I suspect heat to the screw top or rib will be required if only to somehow shock the thread system into submission. ...if not drilling the screw heads out (I dread trying that....what kind of bit do you use for that effort?. Sounds like a mill is required.). Might follow that with an ice cube since I have no dry ice. Proceeding cautiously.

Incidentally, (since we were mentioning screws glued in place) the adhesive product "Rocksett Engineering adhesive" (www.Flexbar.com) is a ceramic cement now in common usage for mounting muzzle brakes, screws, etc. since it resists vibration and temperature extremes (-180 thru +1100 deg C) unlike loc-tite which essentially fails with heat.

I emailed Chapuis via their website as follows:
Me: ".... The (4) existing screws which hold the two small top rib mount "covers" in place are much too tight to easily remove even with fitted screwdriver blades (Wheeler engineering gunsmith screwdriver set). This is despite soaking their heads in Kano Kroil penetrating oil for two days. There was no evidence of rust and I do not believe the screws are rusted in place. They are screwed in very tightly, though I cannot tell if it is the screw heads or the threads that are binding.
The screw heads are somewhat soft and subject to deformation as they were each slightly deformed the the factory screw driver blade during installation as observed when I originally purchased the rifle.

What is your recommended procedure for removing the existing screws please?
Were the screws glued in place? Do they require heat for removal? How and where should the heat be applied? Is an impact screwdriver tool required?

The Factory Reply:
"Hello Sir,
Regarding your problem of removing the top screws, there are 2 possibilities but first the screws aren't glued!!!
1 / You should use an impact tool and slightly tap on each side of the band and on each screw. Use a screw driver that is excatly the same thread of the screw.
2/ if this does not work you can heat very lighlty the top of the screw. do not over do it
as the band is welded with tin . and remove the screws.

Usually either way works
Hope this will help you
Regards
Xavier Cotaz Bertholet"

So: screws are not glued. (Good to know.) band = top-rib. Tap the top-rib(???) and the screw.
If that fails cook it...but not too much. Kind of matches up with previous suggestions. Now I just have to find "a screw driver that is exactly the same thread of the screw". What could go wrong... -RS

If your screw slots are already buggered up, just drill them out using a drill press or mill, and a center drill. That is a real short stiff drill with a fine point made so as not to walk and used to accurately start holes. Do not try this with a hand drill. That is the safest way in order not to damage your rib. Using a hand held screwdriver is a good way to slip and gouge something. You won't need the screws again anyway. I don't like the idea of impact drivers on DR ribs. Something was lost in translation with the "same thread" thing. They mean, as you know, the same size as the screw slot.

What has happened?

Regards