Extending the length of a sear arm without welding

[rich pierce]

Sets of lock castings bring all sorts of unexpected challenges because they copy originals, without considering whether the lock as it is cast will work well in a variety of situations. In this case, after assembling my new build I found the sear arm was short enough that it did not pass beyond the trigger plate. Not sure why I hadn’t noticed that. Seemed to work during the build but maybe just barely.

So I made a lap joint extension with a piece of 1080 steel, pinned with a 1/16” rivet, wrapped it tight with tie wire, and brazed it using propane torch and a brick cubby. I figured this might be suitable for a period repair. There was not enough extra material to draw it out, and welding something this tiny in a forge seems risky. I wait till the braze has run, then file and polish it. Then I re-harden and quench without worrying about the braze joint, as the hardening temp is less than braze flow heat. Then I temper to 450 in sand-filled can for an hour. You can see the rivet and braze joint after cleanup, hardening, and quench better.

 

[waarp8nt]

That looks great!

 

[PathfinderNC]

Your attention to detailed work is amazing.

 

[TDM]

Very nicely done @rich pierce

 

[rich pierce]

Thanks guys. The pin/rivet and tie wire is to keep the 2 pieces together and aligned. I find this one of the biggest challenges when not doing “modern” welding, where it seems one can tack the pieces together. My process requires a lot more cleanup. The funny thing is that the oxidized tie wire, not cleaned, brazes to everything just as well as the pieces I carefully clean.

 

[SDSmlf]

Sets of lock castings bring all sorts of unexpected challenges because they copy originals, without considering whether the lock as it is cast will work well in a variety of situations. In this case, after assembling my new build I found the sear arm was short enough that it did not pass beyond the trigger plate. Not sure why I hadn’t noticed that. Seemed to work during the build but maybe just barely.

So I made a lap joint extension with a piece of 1080 steel, pinned with a 1/16” rivet, wrapped it tight with tie wire, and brazed it using propane torch and a brick cubby. I figured this might be suitable for a period repair. There was not enough extra material to draw it out, and welding something this tiny in a forge seems risky. I wait till the braze has run, then file and polish it. Then I re-harden and quench without worrying about the braze joint, as the hardening temp is less than braze flow heat. Then I temper to 450 in sand-filled can for an hour. You can see the rivet and braze joint after cleanup, hardening, and quench better.

Definitely an outside the box creative repair. Good job.

 

[barracudadave67]

I just extended the sear on a lock. It was a double set trigger, and I Changed it to a single trigger. Doing so I tig welded an extension on. I have a nice trig pull now.
Rich, you did a nice job on the sear. I'm impresseded.

Dave

 

[rich pierce]

I just extended the sear on a lock. It was a double set trigger, and I Changed it to a single trigger. Doing so I tig welded an extension on. I have a nice trig pull now.
Rich, you did a nice job on the sear. I'm impresseded.

Dave

Thx. I’m often tempted to learn welding but am aware that like anything it takes training and time to become good at it. Focusing on period techniques at the moment.

 

[Rebel bull]

Thx. I’m often tempted to learn welding but am aware that like anything it takes training and time to become good at it. Focusing on period techniques at the moment.

it also is a diminishing skill (the less you do the less your skill stays good ) but have seen a sear extended with a roll pin taped on to it not only extends it but also fattens it up

 

[Flint62Smoothie]

I once heated up and press fit a short section of 1/8" metal tube onto the end of the existing sear arm to lengthen it.

Works like a charm ... I just won't take that lock out and show Mr. Pierce!

 

[tallPercshooter]

I lengthened a sear arm by filling a fired .22 case with JB Weld, pressing onto sear bar, wiped off excess, has worked fine for years. Will never be seen.

 

[LongWalker]

Years ago I did a silver-soldered half-lap extension of the sear arm on an old lock I was re-purposing. I think I like your approach better, Particularly when using some of the available sets of castings.