I picked up the "three pack of TS-45s for nearly no money" not long ago, and have had great pleasure in bringing the details of these low powered but accurate shooters up to a functional condition.

One of the aspects that needed significant attention was the heavy direct sear trigger. Inspection of the latch and sear on each of these rifles confirmed that the metal was not near hard enough. In all cases, a file would cut both components.

I purchased some "Cherry Red" hardening compound and processed each of the three rifles as I had them apart for various reasons. The first two are really working great, and I thought I might really harden up the last of the three.

Well, the original latch rod must have had a little carbon in the mix, maybe they stirred the pot with wooden sticks, because after doing the hardening process, a round of test firing was called short as the gun would not cock.

Disassembly showed the the nib had broken off the piston latch rod just where you would think it might. I never thought I would need to temper the Chinese steel. Underestimation!.

Well, I've been looking for just this excuse to make up a new piston assembly, but as I was picking through the stock box, an entirely different idea passed through my head. Fit a piece of HSS or Carbide at the latch sear interface!.

Since I didn't feel a first try prototype was worth the effort required to shape carbide, I grabbed a short bit of 3/8th square HSS. Squared it up on the surface grinder. Prepped the broken latch rod square with the same machine. Cobbled together a jig to hold everything in lignment while I brazed the two together. Viola! Two had become one...composite construction! Hybrid functionality!

When the parts cooled down (Slowly ;_) Final shaping of the latch end was done. First with files to remove the extra brazing rod, then with grind wheel followed by slip stones to shape up the new end.
(Hard as..ahh...err...High Speed Steel! )

It sure is easy to maintain a square sear face geometry this way!

After it's all back together, the trigger action is much improved again. Hard steel on hard steel is a good combination.

I'll need a few hundred shots fired before I claim the entire effort a success, but so far...It's GOOD!

Notes from the machine shop!

I was always tempted by these cheap package deals.


"i never was much for book learnin"

R9 pistons from scratch. The first latch rod I made was W1 (water hardening) rod and the first time I cocked the R10 the latch rod catch let go. I was still holding the muzzle when latch broke so no damage to the gun was done, but I did a bit of experimentation after that. I found that the root of the latch rod notch would crack when plunged into water during the hardening process. I did find that if I quenched the shaped latch rod in hot brine I could get hardening without cracking but I started looking for a better process.

Later O1 (oil hardening) tool steel was tried and for milling the root of the catch I used an end mill cutter with 1/32" radius corners so there wouldn't be a sharp fracture prone corner. Quenching O1 in old engine oil plus tempering to a straw color worked well for me. To test the latch rod prior to installing it into the piston shell I literally pounded the latch rod into a tight press fit hole in the piston end cap with a steel hammer. If the hook on the latch rod didn't break installing it into the end plug, it wasn't deformed by the hammer, and a file would skate on the surface with moderately light pressure I considered the hardening/tempering to be a success. Actually, I used my last home made R9 piston for several seasons then replaced it with a brand new factory piston that I bought for less than $40.

Here are a couple pics of made from scratch pistons..........

R9
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Various latch rod hood fabrications above a factory R9 latch rod. I ended up using the top rod configuration and the pic even shows the tempering color after the hardening.
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Homemade latch rod hook engagement in Rekord trigger.......
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Milling a cocking shoe slot in a R9 piston body with latch rod/end cap assembly shown in front of an old drill press vise. The latch rod shown in this pic is the one right above the factory latch rod in the "3 latch rods" pic. LOL, this was done on my ole HF mill/drill with the MT2 spindle.....
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Or even come close to cracking "

That was my suprise.

The HSS "fix" is fun, and something I've wanted to do...

Cheers

I'm thinking that it's probably made of plain ole cold rolled steel. If your latch rod is similar (don't know if it is), I wouldn't expect it to be hard enough to fracture.