OK, I'm getting desperate. I have an old M98 receiver I aquired years ago. It's somewhat ornate but not mint. It has claw mount bases and I'm finally getting around to doing something with it. Probelm is the screw holding the slider in the rear (grasping) base is buggered. I want to disasemble the base for bluing because of the moving parts and the spring. The top of the base is engraved so I prefer not to try deepening the slot. The screw is sub-4-40 size so too much torque is iffy as well. Already soaked with kroil, tried pressure while trying to turn, etc... Heat is out because of the spring. Any other suggestions before I resort to drilling it out and re-tapping?

Sometimes you can heat just the screw.
Touch a soldering iron tip to it or shield everything else from the torch.

If it is an Allen head screw, a tapered wrench can be ground and pounded into the hole.

No hole? you could drill one.

You can still heat area with or without the spring. You just don't want to over cook it. You want to apply just enough heat to the area to cause an involuntary use of the "F..." word when you touch it.

Also, if it is an allen head screw, you can usually increase the bite by using an appropriately sized torx bit.

I've found PB Blaster to be a real life saver on tough screws. Give it at least an hour to penetrate.

TIG a dot of 680 on top of the screw then repeat over and over until you build up 6 or 8 drops strait up.Then clamp vice grips on the weld and the screw will always come out.

If you can get an Easy-out that small you could try that. You'll mess up the screw but its not at drastic as drilling and re-tapping.

Best of luck.

quote:

Originally posted by ted thorn:
TIG a dot of 680 on top of the screw then repeat over and over until you build up 6 or 8 drops strait up.Then clamp vice grips on the weld and the screw will always come out.

+1. I have done the same many times. If there is any of the screw left, you could also tig or heli an old allen wrench's short side right to it. By the time you have kroiled it a few times, it should give just the right leverage.

I'd really like to see someone TIG the head of a 2-56 screw that is slightly recessed. Now, that's a welder!

quote:

Originally posted by Toomany Tools:
I'd really like to see someone TIG the head of a 2-56 screw that is slightly recessed. Now, that's a welder!

It's not for the odd welder only pro's.

Use sub 50 amp variable foot pedal and .031 rod. and also the most important part...25 years TIG welding and miles and miles of beads...one drop at a time.

quote:

Originally posted by Toomany Tools:
I'd really like to see someone TIG the head of a 2-56 screw that is slightly recessed. Now, that's a welder!

What you do is stick the tungsten too it.

quote:

Originally posted by ted thorn:

quote:

Originally posted by Toomany Tools:
I'd really like to see someone TIG the head of a 2-56 screw that is slightly recessed. Now, that's a welder!

It's not for the odd welder only pro's.

Use sub 50 amp variable foot pedal and .031 rod. and also the most important part...25 years TIG welding and miles and miles of beads...one drop at a time.

Of course to be of any substance, each drop has to land on an equally molten drop. Gotta be pretty quick!

I used to build railroad ore cars for Kennecott Copper Corp in a former life and I would send each new ore car out of the shop with a coke bottle welded to the side. The railroad inpectors knew who's car that was.

I think I have the same exact problem...

But mine is a set screw that was somewhat flanged where a peep sight would mount. The flanged part was set to far.

And they spunn it in too far to be retrieved... I still have a slot to work with but I killed evry small driver I had to get it out. Even after heating it.




same situation but in a different location at this moment I have only 1 secew holding that peep on.




cal30

quote:

Originally posted by cal30 1906:

at this moment I have only 1 secew holding that peep on. cal30

Well, that can't be very good.

Take it to a machine shop or a gunsmith and see if they can't drill it out for you. Should be a piece of cake!

quote:

What you do is stick the tungsten too it. Big Grin

Now there's a time-saver!

quote:

What you do is stick the tungsten too it. Big Grin

You've been watching me weld, haven't you.

To be honest, I don't think it's a bad idea

oupa

Take a good fitting screw driver insert, put it in the slot and tap it smartly with a small hammer. Then mount the receiver in a padded drill press vise, chuck up the screw driver insert, line the screw axis up with the spindle as accurately as possible, remove the V belt driving the drill press, bring the spindle down with firm pressure on the screw, turn the screw out by hand with the pulley on the drill press.

You may need an assistant or third hand for this. It has worked for me many times.

Thanks for the suggestions. To be perfectly honest the welding route is totally out. The screw is simply too small and the surrounding part(s) too close. Great idea for future reference but not an option on this one! Tried direct heat via a red-hot pin applied to the head but didn't help. The (slotted) screw is just too far gone, cammed very badly somewhere in this old receiver's history. It's recessed into an engraved surface and I'm pretty much resolved to simply drilling it out and re-tapping. Size is about #2 and maybe 3/16 inch long, metric I'd guess. Tried gingerly deepening the slot but there can't be much head there. If I'm going to drill I prefer a nice flat surface to start rather then trying to center the shaft of a #2 screw!!!


Craftsman, you were posting as I typed the above. Good idea!!! I will try it before going the more ham-handed drilling route. Thanks!

The only other thing that wasn't mentioned is to try a left handed drill bit. Use a screw machine length drill. SnapOn sells a set but I don't know if the set has one that small. Put it in a drill press and you can see it starting to back out and then let off on the pressure. If you can't get a snapon use Chicago-Latrobe style 157L.

Thanks for all the suggestions. It's out! Ended up drilling after all. Tried the SD bit in the press idea, good try but ultimately failed and pretty much cleared out the last remnant of the (head) slot. That's when I went the drill route.

As it turned out it was actually a pin!!! Had a screw-type head complete with slot but when I drove the last bit out the bottom there were no threads - and no, they were not sheared off. Must have been a press ift from the begining to be so tight. Can't understand why it didn't spin unless it was eccentric maybe??? Anyway, it's out and now I can do my work and figure out how I'm going to replace it when the time comes. Thanks again fellas!

Or, you can drive it out like a pin.

One in every crowd eh westpac?

Actually there was not enough room beneath the base to drive it out from there even if I'd known it was a pin. There is the possibility that the head or a shoulder just under the head (like on a Mauser ejector box screw) was threaded and was obliterated by the drilling. I'll never know now. Have to assue though that it was held fast by the engraving that was done over the head as part of the overall engraving, thus essentially sweging it into the surrounding metal. Again, I'll never know...

quote:

Originally posted by ted thorn:
TIG a dot of 680 on top of the screw ...

What is 680? Is that a low carbom rod or something? Are you talking about just fusing the rod to the head of the screw and then turning the rod?


I did not need to ask about Malm's method. I practice sticking tungsten all the time!

quote:

Originally posted by Marc_Stokeld:
I did not need to ask about Malm's method. I practice sticking tungsten all the time!

Actually there are times in gunsmithing when the skill and ability to, with acute precision, stick the tungsten is necessary. Like those times when you have a round object that has broken off in a round hole and simply won't fall out, such as the front leg of a 1911 ejector, or a jamed up bolt nose ejector. If you can stick your tungsten to the head of a pin, you will be good to go on those rare occasions when such a skill is needed. On those occasions, an Auto Darkening hood will come in handy.