Can I / should I drill out a stuck pin?

[Morglan]

I'd like to replace the bent lanyard loop on my Sistema (I want to keep the MSH because I love the checkering), but the pin holding it in will not budge.

Can, or should I drill out the pin? Any advice?

Thanks!

 

[Onmilo]

You could try soaking the mainspring assembly in Kroil oil for a couple of days and then heating the area around the pin to way too hot to hold with a propane or MAPP gas torch allow it to cool a bit, and then try smacking the pin out.

If that doesn't work you could try drilling the pin out but you would need, at minimum, a high speed steel bit and a fast running drill press.

A hand drill and a WalMart drill bit will cause you nothing but pain, anguish,suffering, and you may be inclined to cuss a bit if you try going that route. HTH

 

[Spartacus451]

How exactly are you trying to remove the pin? Have you lowered the hammer? It makes pushing the pin out easier. I can think of no ordinary circumstances where drilling might be necessary.

 

[Morglan]

How exactly are you trying to remove the pin? Have you lowered the hammer? It makes pushing the pin out easier. I can think of no ordinary circumstances where drilling might be necessary.

No--the mainspring housing is off the frame. There's a tiny pin that passes across the base of the housing, passing through each "prong" of the lanyard loop to hold it in place.

I have a replacement lanyard loop (not the entire MSH--just a new loop), since I really wish to keep the original MSH, my goal is to simply replace the bent loop with the new one.

Onmilo--your suggestion has promise. I may just try that. The only problem I can forsee is transitioning from a position where I can hold the heat on the MSH to a position where I can try to drive out that pin.

 

[Jim K]

Drill only as a last resort as drills have a tendency to wander.

Those pins are a drive fit, but of course can be rusted in. Try the soaking and heat first. If that doesn't work, clamp the MSH firmly in a brass or copper jaw vise, use a starter punch (very short end so it won't bend) set up carefully and WHACK IT. Either direction.

If you have to drill, use a center punch carefully, then use a starter drill (again, a very stiff drill with the drill bit itself very short).

Jim

 

[Morglan]

Either direction.

Thanks for that info Jim--I was wondering if it mattered which way I went.

I'll try soaking it overnight tonight, and then firing up the torch tomorrow.

 

[mrmeval]

Is that a pressed in pin? If so you might need an arbor press to remove it.

 

[Morglan]

How can I tell if it's a pressed pin? (Did they press pins in 1954?)

 

[Onmilo]

Being a Systema it is probably pressed in but who knows for sure?
I have a Systema pistol and several mainspring housings, the pin is not cup pointed like most Colt and I will bet money the steel isn't quite up to the Colt standards either.
I have removed quite a few lanyard rings for just the reason you wish to and have not yet had to resort to an arbor press to get a pin out.

Jim Keenans starter punch suggestion is a good one.
You can secure the heated housing in a good quality vise between two vise jaw pads made of 1/16" thick brass sheet to prevent the jaws from marring the housing.
Use a welders glove or good pliers to hold the heated part while securing it in the vise
As for drilling, I use half length jobber drills for this kind of work and trying to center punch a 1/16" or 3/32" pin is well,,,trying.
Use a drill press and high speed steel bits. You will need at least 600 RPM on the spindle. 800 rpm would be better if you can get it.
Secure the part well in the drill press vise and make darn sure the pin is 90 degrees to the drill bit, use a bench level.
Peck feed the drill bit into the pin/hole, drill a little bit at a time and withdraw the bit and clean by hitting the rotating bit with an acid brush dipped in drill oil, this will keep pin chips from building up in the new hole and then cutting the hole out of round or oversize.

More advise for the vise and punch method.
You support the area to be punched above and resting on a pin hole of a bench block that has a wood block underneath to bring it to the height plane of the part.

The securing pins vary in diameter from 1/16" to 3/32" in diameter.
If you redrill the hole you can go up to 5/32" in pin and hole diameter but it will really hog out the lanyard pin slots.
Green #609 Loctite retaining compound placed on the lanyard ring posts and on the new pin will ensure the lanyard will not jiggle and the new pin will not drift out if you get sloppy. HTH

 

[Morglan]

The securing pins vary in diameter from 1/16" to 3/32" in diameter.
If you redrill the hole you can go up to 5/32" in pin and hole diameter but it will really hog out the lanyard pin slots.

I bought a Smith & Alexander replacement loop from Brownell's. It comes w/ a 3/32 roll pin to hold the loop in place, and calls for a #40 drill bit to make the hole. (Since the pin hole will already be there in the MSH, I'll simply need to drill through it to make the holes in the loop.) Since I could not find a #40 bit locally, I'm going to use a 3/32 bit, which is only .0042 of an inch smaller than the #40 bit (really shouldn't make a difference.)

I am going to have to rig something up to hold the MSH in place while I try to pound out the old bit. I made a starting punch out of an old 1/16 punch that I had bent. Should work well.

 

[Morglan]

Well I finally got the pin out--didn't need to heat it after all, just soaked it in some Penetrating Blast for a while, then it pounded right out.

Got the new lanyard loop in there (used the locktight too), and drilled through the pin hole into the legs of the loop.

I could not get the original pin to go back into the hole. Wouldn't even start.

I drilled out the entire hole with a 3/32 bit intending to use the new pin supplied with the new loop, but ended up using the old pin and locktight.

I don't anticipate any trouble with it, and am very happy with the way it came out.

Thanks for the help!