C96 Stock repair ?
 

Hello all, I was wondering if anyone can suggest a way I can remove a broken screw from a C96 stock. It's the long retaining screw that holds the mounting bracket. The screw seems too small to drill and get a good enough bite on to extract. If it wasn't original I'd just drill it out and retap but the stock is orig and in great condition besides that screw. Has anyone ever run into this situation ? I clipped a sarco picture to show the screw I'm talking about.
Thanks Rick

Take a steel awl and heat it to the white-hot level then apply it to the tip of the screw and hold it there until it begins to cool. The heat will be transferred down the shaft of the screw causing it to swell. As the screw cools it will retract thus breaking the bind. It always works for me.

That sounds good but the head of the screw is snapped off. Only have access to the thread end, and very little access. I could heat that but then no way to turn it.

Does the picture have anything to do with the question?

Other than it is a stock iron with screw?

Is the Iron still in place on the stock, with the screw in place- except head is broken off?

Then only chance is to drill the threaded end with a carbide drill, using a millng machine and remove the just out to the threads, then tap the screw body out the other way.

Clean out the threads or re tap to the original size.

A tricky and delicate procedure, IMO.

+ 1 :thumbup:

Yes that was just a ref pic. It's still attached. Guess I'm off to the depot for a couple of bits. Thanks for the suggestion.

Be sure to start your drilling "dead center" or the result will not be good!

The ends of most of those screws are domed, and thus the bit will "skitter" around, you need a sharp and inflexible bit to get on dead center.

Thanks Don, I'll let you know how it goes.

To avoid the bit running around on the domed end of the screw, use a center drill first, as they are made for this type of job, and won't flex at all. Then, once you have a small start in the screw, you can go after it with a standard high speed bit. Just make sure it is NEW, and this is its first cut. Take short cuts, with a drop of oil, and blow out the hole frequently. Go slow, no need to hurry the job.

Or you can use a Dremel and a small diamond burr to make a divot. This gives you a second chance to get it on center, as you can simply grind it the direction needed to get it dead on.

Even with a center drill, it will be difficult to get the initial divot/hole centered. This is due to the thread and hole exhibiting an 'off-center' appearance. Looking at it as it is installed, the thread shows the apex on one side of the hole/screw and the root on the opposite side.

If the screw is 'finished' flush with the stock iron then there won't be any dome.

A tricky issue even for an experienced machinist. :(

I'd give it to Gerry Tomek! :D

The trouble is cost. If don't count cost, drill a bigger hole on iron to take those screw off. Fill the hole by TIG, machining the weld into shape, recreate the hole and screw threads on the iron. Reapply fire blue on it, it will look brand new.

But what's the cost of doing this way.. the result value definitely won't cover that cost. So, no. If this damaged screw was just not pretty, I would say just leave it alone.

Besides all this,what I usually do in this situation, (not my first rodeo), is chuck up a carbide dental burr in the dremel, spin it as fast as it will go, and "paint" a new slot in the exposed end of the screw, then just use a flat bladed screwdriver to spin it out. Usually by doing this, it releases any existing crush, or tension on the threads, and the screw spins right out. I get broken scope mount screws in the shop pretty regularly. I'm sure this is bigger than the 6x48 mount screws I usually deal with, and therefore, probably easier to take care of. But, as I tell my customers, "minor miracles on a daily basis".

I think I would soak it in oil for a while, dry it off, heat it up a bit to help loosen the rust then grab the shaft of the screw with a pair of vise grips and wiggle the screw back and forth until it breaks free then unscrew it. If the vise grips bung up the shaft too much to get it out of the frame, cut the shaft and remove from inside the frame. Nothing like a BFFI (brute force and flipping ignorance) approach to a problem, eh what? :)

Unless the head was broken off while trying to remove it, and the shaft is still inside the wooden stock... :rolleyes:

delimma
 

Reluctant to drill it out and lose my threads. The head of the screw is missing, just a hole. If it was an aftermarket stock I wouldn't hesitate

Sorry, I misunderstood...stupid mistake, I should have known it was still on the stock. Drilling is probably the only option and an experienced machinist/gunsmith is a good recommendation.

No worries, it's a learning experience. And can't think of a better excuse to pop for a better drill press.

screw slot
 

Looks like some of the screw is sticking out of the hole. How about soaking with kroil and them grind a screw driver slot with a steady hand and Dremel and smack it sharply to loosen and try to screw out.

This is not the original screw there. Looks the tip is hex shaped, installed by a special tool. But this must be there for a long time and match this stock's overall condition. A new replacement screw won't make it prettier for sure. Downgrading for fun, I guess?

If it was mine. I might say I am not too heavy into C96 apparatus.

a drill press is not a mill. I personally think the mill is the best machine for this attempt, just an old guy's opinion. The mill is lots more stable left/right sorta speak.

I would ponder the actual line of travel thru the stock of the screw , and try to get that line upright to the cutter. Not sure how to do that other than by careful eye, and then use an indicator to center the top of the screw proper the best I could.

I think I would use a carbide centerdrill to establish the divit for the drill to follow. The carbide and the attributes of a centerdrill(relative stiffness) will help get things started.

Screws are not too hard I do not think, so a HSS drill(135 degree) would be my choice, unless I had carbide drill on hand. Let there be gentle movements.

A little Kroil on the bottom existing screw/steel support would not hurt before using an easyout. I do not know if the screw is threaded on top and on bottom, but a little Kroil helps threaded objects come loose with judicious persuasion.

A bit touchy to set up, but is done everyday really.

Alvin,
that is not the "tip", but what is left after the head broke off.

If the screw was stuck bad enough to break off the head, you are going to have major problems getting it out, it is probably "rusted" and stuck in the wood.

Drill out the bottom, then drive out the old shaft bottom to top.

Or just leave it alone.

+1

And glue a screw head in the broken-off hole. :)

Broken head screw should NOT break on the tail end. Please note the both pictures shown in post #16 are screw's tail end, not head end.

Thanks Alvin, my photo abilities are in desperate need of improvement. I see an iphone in my future. Both pictures are of the tail end, just a black hole on the screw head side. I've thought about another option that may not be righteous to any future owner if I'm not around to explain. But since the stock is functional but only loose on the screw head side, I'm inclined to epoxy it, lop of a correct screw head and epoxy that into the hole. Out of sight, strong and functional and without the possibility of destroying the piece. The value of the stock is already compromised and in my eyes downgraded to "shooter" status now regardless of its pristine appearance. Any thoughts on which type epoxy would work best?

Well, that changes everything. :rolleyes:

How about sticking a rod down the 'black hole' and see how much of the screw is actually left? If that is the bottom of the screw, then you would only have to drill out about 3/16" of the screw x base diameter of the thread to break it loose and drive it out. Then you can separate the wood and pick out the pieces of thread and clean up the tapped hole.

It's actually gotten easier. :)

Thank you all for the advice. Finally got the SOB out and recut the thread (I think the same size). It did take two new carbide bits due to busting the first. Went with the dremel suggestion to dish out the center first, thanks Olle for suggesting. Now just to find the correct replacement screw without having to buy the whole mounting bracket.

For sure your description and pictures are at best "confusing".
If that is indeed the tail end in the picture, someone has already drilled and monkeyed with it!:eek:

Well, now-

how about pictures of both sides and "what ever" you got out of the stock?

Why would you re-cut the thread until you have the screw and know the diameter and thread pitch ?

Sharing info is good.:thumbup:

Well I don't know Don, just seem the right thing to do. The tap looked to fit and turned through with not much effort like it was following. If it's too small I'll make it bigger. Haven't been able to find just the screw w/o buying the complete hardware so worse case is I'll have to make one.

Good old ebay $10

ebay is full of goodies.

Didn't you mis-spell 'goodies'??? :)

Great deal, hope you got it.:thumbup:


Threads look a little coarse, but then there is no reference.

I've pre-drilled and pre-threaded before, and at least half the time I then wished I had waited!
Maybe you are luckier than I am.

Goodies. Fixed.

Looks being a replica. But it fits the role.

Don, just an update on those threads. My ebay screw arrived today, ended up being a 6-32.

Thanks for the info.

You can get an exact duplicate if you want one.
One of the forum members had some made- but they are not cheap.:eek: