Help - My amateur smithing has gone horribly wrong...

[Dorrin79]

So, to make a long story short, I ordered a new extractor spring for my FM Hi-Power that was having FTE problems.

I used a pick to "properly" clean the extractor channel, and hammered it all back together.

In the course of this, I ruined the Sear Lever Retention Pin (which you have to remove to get at the extractor)

So, I ordered a new one.

It came in over the weekend and I used it to put the gun back together last night.

I was a happy camper until I tried dry-firing it - the trigger pull, previously a crisp 5 lbs, had gone up to more like 15 lbs



I think I figured out the problem - the new Sear lever retention pin is oversized, and is binding the sear lever too tightly and preventing it from swinging freely (with the old pin, the sear lever moved back and forth with no binding.

So - how do I fix this? Can I sand down the hole through the sear lever to allow it to swing freely - and if so, how do I do that?

Thanks!

 

[Old Fuff]

I doubt that the pin is too big, it's more likely that the sear bar is binding on something in the slide. The original bar was fitted at the factory, not just "dropped in." I would remove the new sear bar and then slide the pin back into the sear bar's hole and see if it binds. Then I would compare the new bar against the old one and see if any metal was removed from the first one, and if so make a similar modification to the new one.

Last but not least, it might be advisable to spend the money on a good gunsmith, but if you continue yourself I'd want to be sure I had the correct punch(s) to remove the rollpins in the slide. Without them you may end up seriously hurting the slide's finish.

Doing you own work is O.K. ... but only if you know what you're doing.

 

[Dorrin79]

Old Fuff -

Thanks for the reply.

The sear bar is the original one, and without the pin, it drops properly into its slot in the action, with freedom of movement.

The (new) pin, on the other hand, doesn't want to fit into the hole in the sear bar. It does if driven with a mallet, but then the bar won't pivot without a lot of force.

Is there any danger in using a file to widen the hole in the sear bar enough to let it freely rotate around the pin?

edited to add - it's a split pin, whereas the original was a solid. I think that may have something to do with the problem...

 

[Old Fuff]

The "split pin" you refer to is called a "roll pin," and is formed out of sheet metal. In any case trying to open up the pin hole in the sear bar with a file could, and probably would result in an out-of-round hole that could cause more problems. If the hole is to be enlarged it should be done with a drill in a drill press. Another possibility would be to make a new solid pin. Such a pin could be made from the shank end of the proper sized drill. Unless you have access to, and experience with, a drill press or milling machine you probably need to see a gunsmith. Either of the above solutions shouldn't be expensive.

One other possibility. If you polish the "split" part of the roll pin with a piece of #400 emery paper (obtainable in the paint section of an automobile parts store or most hardware stores) you may remove a burr and the problem will be solved.

 

[Ironbarr]

Are you sure that the new pin is sized properly? People who package things do make errors. Call your supplier.

 

[ksnecktieman]

replacing a solid pin with a split pin????? I think I want to call "wrong part" on this one. A split pin is designed to hold things that do not move. A solid pin is always? used for a pivot.

 

[duckfoot]

ksnecktieman

A split pin is designed to hold things that do not move. A solid pin is always? used for a pivot.

I had better get the roll pin out of my trigger guard on my AR-15. I believe that the dynamic stress placed on that pin might determine weather a solid pin, roll pin, or split/cotter pin should be used. A pin that gets hammered on, while the pistol cycles should be beefier than a pin that hold a latch lever in place.

 

[ksnecktieman]

duckfoot,,,, I bow to your superior inteliigence,,, I only fix cars for a living,,, BUT if he removed a solid pin,,, and installed a split pin he has modified it,,, they are not interchangeable parts. They were not designed for the same purpose,,, split pin is a retaining device, and a solid pin is a pivot, flexible connection?

remove my previous post if it is idiotic please,,, all I have on my side is logic

 

[ksnecktieman]

dorrin,,,,,,,, the first rule of shade tree repairs,,,,,,,, modify the cheap stuff. do not change the hole, you have the same hole you started with,,, modify the pin,,, do not destroy anything that DID work,,,,,,, grind that pin down to a toothpik, before you ruin any other parts

 

[duckfoot]

ksnecktieman

split pin is a retaining device, and a solid pin is a pivot, flexible connection?

I agree about the split pin being the wrong part for the job, I was putting a different spin on the point. No Flame intended, just, thinking out loud. I’m not a mech of any sort but, having worked on all manner of machines from computer mother boards to mounting a Cummings 600 in a 18 wheeler I tend to look at problems from the most basic viewpoint then get technical, because missed details are a Fother Mucker.

modify the cheap stuff.

Wisdom, if I have ever heard it, for a fixer of machines.

 

[Old Fuff]

In years past Browning/FN used a solid pin in this application. More recently they changed to a roll pin. For what reason I don’t know, but I suspect it might have been something too do with cost.

Anyway, it’s clear that this gun’s owner wants to fix it himself, and may or may not have the necessary knowledge, skill and tools too do it. So I laid out several options, leaving the choice to him. Unfortunately most of today’s manufacturers are driven by cost considerations regardless of how small they may be.

One other point comes to mind. When you order replacement parts for your gun, be sure to include a full description of the gun and include the serial number. That way there is less chance of a mix-up of the kind that’s apparently happened here.

 

[Dorrin79]

Old Fuff -

Agreed that I lack the parts and experience!

I may see about fashioning a new pin from a drill bit, as you suggested.

If that doesn't work, off to the gunsmith we go.

I know when I'm beaten...

Thanks for all the advice and replies. I'll let you know if I have any luck...

 

[Old Fuff]

When something like this comes up I try to be helpful, but at the same time I usually have no idea about what the person posting the question can reasonably be expected too do. Our members rank from excellent authorities on almost any firearms subject, to some I think aren't sure which end of the gun a bullet comes out of. So I try and make an educated guess about who and what I'm working with.

In my case, making a pin woud be quick and easy. In yours, it may not be. But while it may take several tries I think you'll get there. Meanwhile you are not doing anything that will hurt the pistol. So have at it. I wish you luck.

 

[Dave Sample]

Roll pins are IN! The drill bit trick is the answer if you can get a measurment off of the old pin. I like solid pins in guns. Numbered bits will tell you the diameter of the bit so you can clean up the hole with the bit and then cut off the sahnk for a pin! Good luck!

 

[Alex]

Before I got my metal lathe I did some good work by clamping a hand drill horizontally to my work bench, careful use of a file and frequent checks with a caliper allowed me to do some fairly accurate work making pins and shortening screws, it isn't ideal by any stretch of the imagination, but when you consider that some of the worlds finest shotguns and rifles were built without aide of powertools than if kind of puts things in perspective, being willing to tackle the task at hand is the most important part, fancy tools help but they do not replace the desire to create that must go hand in hand with the total process. Good luck and happy tinkering.

 

[Jim K]

That pin does not take a great deal of strain and a roll pin is entirely adequate to the job, as well as a lot cheaper. Making a solid pin would be OK, but not (IMHO) necessary.

I agree with working on the cheaper part. If that is a common size roll pin, you can buy them for a few cents at the hardware store, and I bet the sear lever costs more than that, if you can get it (it may be a restriced part).

So file down the roll pin. You don't need to file it down for the whole length, just where it goes through the sear bar. The pin squeezes down when driven in and when it gets to the right place, the small part will be in the hole of the sear lever. That way, you get the proper retention as well as proper clearance at the lever.

Jim

 

[Dorrin79]

the rest of the story

Spent a good 1/2 hour with some extra fine sandpaper, sanding the pin, Friday afternoon until the sear lever rotated freely about 1/2 way up the pin.

Reinstalled and (ta-da!) trigger pull was restored to it's old level.

Took the gun to the range Saturday and put 200 rounds of the previously FTE-prone WWB 9mm through it with no failures.

So all's well that ends well.

Thanks for the advice, all!

-Dorrin