T/C Trigger Lightening

[TrophyGuy]

Anybody have any luck tuning a T/C lock down to a reasonable non-set trigger pull. Mine works fine in set trigger mode, but pulls a number beyond the scale of my pull gauge. Feels like 20 lbs. I've polished the sear spring hole to stop most of the coil crunching. I would like to stone the sear surfaces but don't want to break through the case hardening, if there is any. I know this is a comparatively cheap lock, but this last bit of tuning looks doable. Any experience or advice?

 

[EC121]

How close is the front trigger pivot to the sear bar? Might be a front trigger pivot geometry problem, but more than likely it is the angle of the full cock notch. To check it take the mainspring out and hold the lock nose down at full cock. Then slowly push the sear bar. The hammer shouldn't move backwards or forwards. It should just disengage and drop of its own weight. If it moves backwards before dropping, the full cock notch angle is wrong and holding the sear nose in.

 

[TrophyGuy]

EC 121, you are correct, but the front trigger pivot is fixed into the geometry of the lock. Can't change that, but you are correct about the full cock notch angle. It is like any properly designed sear, a slight negative angle for safety, the cause of hammer movement. The problem is sear engagement length. It's almost 1/8 in., all of which must be scrubbed off when the trigger is pulled, making for a lot of creep and a bunch of pull weight. I can't see a ready way to lower engagement length except grinding away sear surface, a chancy thing to do. I'm trying to find a replacement sear spring to lower the sear pull weight. I could always chop off a coil turn but thought somebody here might have tried that.

 

[EC121]

With the proper angle you should only get creep not excess trigger pull weight. Sounds like you are pulling against the mainspring. Put a spring out of a ballpoint pen in it for troubleshooting.

 

[Kansas Jake]

Weird on the trigger pull. I don’t have a clue other than I have two TC Hawkens that were kit built and a Renegade factory build and all three have decent unset pull weights. I’ve never bothered to even test them.

 

[TDM]

Anybody have any luck tuning a T/C lock down to a reasonable non-set trigger pull. Mine works fine in set trigger mode, but pulls a number beyond the scale of my pull gauge. Feels like 20 lbs. I've polished the sear spring hole to stop most of the coil crunching. I would like to stone the sear surfaces but don't want to break through the case hardening, if there is any. I know this is a comparatively cheap lock, but this last bit of tuning looks doable. Any experience or advice?

I have a set trigger Renegade and a single trigger New Englander, luckily no problems with either. I’d follow the advice of EC121 and I’d disassemble and go over the tumbler, sear, and trigger arms with a fine stone. Your not likely to hurt anything with a good stone, only help.

 

[nit wit]

I put a Davis triggers in My Renegade. The front unset trigger works better than the T/C trigger.
Nit Wit

 

[Eric Krewson]

Have you looked at the top of the trigger bar, every TC I have had looked like a washboard. You can polish the trigger bar; I used a light touch with a fine needle file first followed by 220-400-crocus cloth and finally a buffing wheel and compound on a Dremel. For the sear bar I just used crocus cloth and the buffing wheel.

On one lock the unset trigger went from 8 or 9 pounds to 6 after the polishing, I was astounded on my latest TC trigger, it went to 3 1/2#. I have polished three locks triggers so far, all improved.

You can see the washboard effect on the part of the trigger I didn't polish. Of the three triggers that I polished this one was the worst.

Here is my second trigger before a polish, these pictures are clearer;

After polishing;

The sear before polishing;

After polishing;

 

[TDM]

That’s the ticket!

 

[ohio ramrod]

The contact angle of the tumbler where it meets the sear is critical. If the angle measured from the tumbler is less than 90 degrees you have to fight the main spring, if it is greater than 90 degrees the tumbler will"push off" and not hold. Almost all factory locks have an angle less than 90 degrees for safety. A simple way to check to see if you are fighting the main spring is to place a small piece of wood where the flint goes, Cock the rifle and turn it on it's side so you can clearly see the cock and slowly pull the trigger, if the cock moves back before releasing you are fighting the main spring. Careful honing of the tumbler notch will fix the problem. Just remember that "putting back on " stones are hard to find.

 

[LRB]

Lighten your sear spring. Cut a loop or so off, a little at a time cut and try. Assuming you polished the rest of the moving surfaces. Also, make a block for the depth of your sear engagement. You can make the block by using a low temp solder and attach a thin piece of steel on the face of the tumbler at the notch, then file it back to get the needed engagement for a positive engagement but no more than that. If too light file the block a bit more. The block can be brass, or even J&B WELD.