Need help with T/C lock

[necchi]

Ok, what we gotta do is get some terminology and trigger function understanding going on.
your TC Double Set Double Throw trigger has two triggers right,,(?)
Each trigger has a "cam" that will push against the locks "sear arm" to disengage the sear from the "tumbler".

The rear trigger cam is supposed to only work when the rear trigger has been pulled back and it's cam "set" into a notch in the front trigger.

Your right,, when "set" the rear cam is fully down and won't interfere with the sear arm.

Two things can happen that will result in the rear cam interfering like you have going on.

1. The trigger plate itself can be too deep in the stock,, this is common with many older CVA/Traditions rifles,, the wood get's dry and people over tighten the screws compressing it and sooner than latter the triggers just get too deep, The fix for this is to shim or bed the trigger inlet to get the trigger plate back in proper position.
2. Usually with the TC triggers the rear leaf spring is pressing too hard on the rear trigger forcing the rear cam too high,, all that needs to be done is to adjust the screw for the leaf spring to bring it down. With the lock out you can look at the cams through the hole in the lock mortise and see where the cams position are in relation to where the sear arm will go.

 

[Mike Boettcher]

Ok, what we gotta do is get some terminology and trigger function understanding going on.
your TC Double Set Double Throw trigger has two triggers right,,(?)
Each trigger has a "cam" that will push against the locks "sear arm" to disengage the sear from the "tumbler".

The rear trigger cam is supposed to only work when the rear trigger has been pulled back and it's cam "set" into a notch in the front trigger.

Your right,, when "set" the rear cam is fully down and won't interfere with the sear arm.

Two things can happen that will result in the rear cam interfering like you have going on.

1. The trigger plate itself can be too deep in the stock,, this is common with many older CVA/Traditions rifles,, the wood get's dry and people over tighten the screws compressing it and sooner than latter the triggers just get too deep, The fix for this is to shim or bed the trigger inlet to get the trigger plate back in proper position.
2. Usually with the TC triggers the rear leaf spring is pressing too hard on the rear trigger forcing the rear cam too high,, all that needs to be done is to adjust the screw for the leaf spring to bring it down. With the lock out you can look at the cams through the hole in the lock mortise and see where the cams position are in relation to where the sear arm will go.

I'm with you on this now...excellent post...this is what I needed to know. I'll look at both options for a fix. Thx!

 

[Mike Boettcher]

Ok, what we gotta do is get some terminology and trigger function understanding going on.
your TC Double Set Double Throw trigger has two triggers right,,(?)
Each trigger has a "cam" that will push against the locks "sear arm" to disengage the sear from the "tumbler".

The rear trigger cam is supposed to only work when the rear trigger has been pulled back and it's cam "set" into a notch in the front trigger.

Your right,, when "set" the rear cam is fully down and won't interfere with the sear arm.

Two things can happen that will result in the rear cam interfering like you have going on.

1. The trigger plate itself can be too deep in the stock,, this is common with many older CVA/Traditions rifles,, the wood get's dry and people over tighten the screws compressing it and sooner than latter the triggers just get too deep, The fix for this is to shim or bed the trigger inlet to get the trigger plate back in proper position.
2. Usually with the TC triggers the rear leaf spring is pressing too hard on the rear trigger forcing the rear cam too high,, all that needs to be done is to adjust the screw for the leaf spring to bring it down. With the lock out you can look at the cams through the hole in the lock mortise and see where the cams position are in relation to where the sear arm will go.

I choose option #2 and bingo!!! Much more simple than trying to shim the entire trigger plate. Thanks for the tips. Only difference is that the screw that adjusts the tension on my rear leaf spring has a allen head...no big deal.

necchi, you be the man.

I'm grateful that you are willing share your knowledge and for educating me on how all these things work together.

 

[necchi]

:wink:

 

[don hepler]

When I have a problem, I try to determine if it's a lock problem or trigger problem. First if the lock functions properly out of the gun, and it is not contacting any wood when it is installed, then it must be a trigger problem. When the hammer is cocked, the sear bar moves ever so slightly downward, just before the hammer falls into the full cock notch. If the trigger bar is too close to the sear bar, then the hammer will not cock properly. One way to check, is to shim the trigger group down, and test it. I have a couple of rifles that have shim in them. To function correctly, there must be a slight gap between the trigger arm and sear arm. When you set the rear trigger, you are actually cocking the front trigger, and when you pull the front trigger, it springs up and slaps the sear bar.

To keep a TC rifle in working order, pull the barrel and remove the nipple, and give it a good cleaning and oiling. Also, remove the lock, and spray it clean and lightly reoil it. Make sure the inside of the cup part of the hammer is clean. Wipe off any excess oil, and reassemble it. Wax the stock and polish it. Don't over tighten the nipple or the lock plate screw. I have four digit TC's that look like they were made yesterday. I check the barrels, often when in storage. I have never had a TC rifle fail to fire, in a hunting situation.

 

[Mike Boettcher]

When I have a problem, I try to determine if it's a lock problem or trigger problem. First if the lock functions properly out of the gun, and it is not contacting any wood when it is installed, then it must be a trigger problem. When the hammer is cocked, the sear bar moves ever so slightly downward, just before the hammer falls into the full cock notch. If the trigger bar is too close to the sear bar, then the hammer will not cock properly. One way to check, is to shim the trigger group down, and test it. I have a couple of rifles that have shim in them. To function correctly, there must be a slight gap between the trigger arm and sear arm. When you set the rear trigger, you are actually cocking the front trigger, and when you pull the front trigger, it springs up and slaps the sear bar.

To keep a TC rifle in working order, pull the barrel and remove the nipple, and give it a good cleaning and oiling. Also, remove the lock, and spray it clean and lightly reoil it. Make sure the inside of the cup part of the hammer is clean. Wipe off any excess oil, and reassemble it. Wax the stock and polish it. Don't over tighten the nipple or the lock plate screw. I have four digit TC's that look like they were made yesterday. I check the barrels, often when in storage. I have never had a TC rifle fail to fire, in a hunting situation.

Any particular oil to be used on the lock after cleaning? I notice in mine when I had it apart that there appeared something almost like a light grease in the spring and some of the other parts.

What do you guys recommend for the lock?

 

[necchi]

Gun oil.
I use Hoppes 9 Lubricating oil.
The key is oil needs to be fresh. Any oil will get old, gummy and loose viscosity with time, usually within a few months.
It pay's to clean and oil locks an triggers on a regular basis.

 

[homebrew .357]

Front trigger slaps sear arm, :hmm: , me thinks when you cock the back trigger it`s this one that springs up and knocks sear arm. It catches in the front triggers notch and is released by it, eg set trigger. Just my nz 2 cents, Cheers Homebrew.357.

 

[don hepler]

Parts that pivot and move with little resistance, only need light oil. I use Remington, but there are many others. On the other hand, parts that are under pressure, need light grease. I am talking about applying white lithium or other gun specific grease with a tooth pick, to the notches on the tumbler, and where the main spring contacts the tumbler, etc.

But, there again I shoot a lot, and that puts a lot of wear on my lock. Really you can get by with just spraying the lock with a light misting gun oil, of your choice, and wiping off the excess. Clean the lock first, with powder solvent, of your choice.

 

[don hepler]

Front trigger slaps sear arm, :hmm: , me thinks when you cock the back trigger it`s this one that springs up and knocks sear arm. It catches in the front triggers notch and is released by it, eg set trigger. Just my nz 2 cents, Cheers Homebrew.357.

That's correct, the trigger group and the lock group are separate of each other, and can be tested independently. In other words, if you were to have the lock out of the gun, and you cocked the hammer, you could fire it by pressing on the sear lever. (Be sure you safely catch the hammer) Also, if you had the trigger group out of the gun and you set the rear trigger (Cocking it) when you pull the front trigger, the trigger arm would be released, and fly upward. Put them together, in the gun, and the trigger arm flies up and strikes the sear bar. This does two things, one the positioning of the trigger bar in relation to the sear bar is a tiny bit less critical than in a modern firearm. Second, the spacing allows the sear bar to ride up into the full cock notch on the tumbler. Because of the positive engagement of the notches, it is critical for the sear arm to move down a few thousandths of an inch, allowing it to drop into the full engagement of the tumblers notch.