Author Topic: TC lock tuning?  (Read 17274 times)

Offline Artificer

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Re: TC lock tuning?
« Reply #25 on: April 15, 2014, 03:14:33 PM »
I'm in Pa. The trigger pull is heavy but crisp. Weighed 8 lbs then after toiling it went to 6 lbs. The trigger modes freely with the lock out, it's seems like the weight. I feel is the sears lever return spring. Perhaps changing the pivot point as suggested will improve it.

Changing the sear spring (what you refer to as the "sears lever return spring") is not going to give you a significant reduction in trigger pull weight, because that is not the spring that puts the most force on the lock parts. 

The purpose of the sear spring is to ensure there is JUST enough tension on the sear to keep the sear nose properly engaged against the tumbler and so the sear nose won’t slip off the tumbler as the lock is cocked.  The TC sear spring tension probably has a LITTLE more spring tension than what it absolutely has to have to perform this function, but it is NOT going to be a whole lot stronger than it needs to be.  IOW, I extremely doubt that a lighter tension sear spring, that will still perform the basic and vital function of keeping the sear nose in proper engagement, is going to give you any more than ¼ to at most ½ pound reduction of the trigger pull. 

It has been suggested that you could get a replacement sear spring from Brownell’s.  While that information is basically correct and well intentioned, it is NOT as simple as calling Brownell’s and ordering a lighter power sear spring to fit your lock as from what I’ve been able to research, they don’t have a spring designed to do that.  What Brownells does sell are “coil spring packs or kits” where one may choose a longer spring of the same diameter (or only a couple thousandths of an inch smaller) than your sear spring and cut a shorter piece to use in your lock.  You need a precision dial caliper to measure the diameter of you coil spring and then purchase the “coil spring pack or kit” that has that diameter of coil spring in it. 
http://www.brownells.com/gunsmith-tools-supplies/small-hardware/bulk-spring-kits/index.htm

Sounds somewhat easy, eh?  Unfortunately, even that description does not tell you the whole story.  You may find the coil spring that is the right diameter to go in your lock is too light or too heavy for what you need.  You MAY have to buy more than one kit to get a spring that will work.  You MAY buy two or three kits and not get a spring you can use.  IF you want to try this route, then I suggest you get the diameter measurement of your sear spring and CALL Brownells and ask to speak to a Technician.  Tell him the diameter of your coil spring and what you want to use it for and hopefully they can suggest the correct spring pack.  This is what gunsmiths do when confronted with looking for springs where one is not specifically made and available for that purpose.

That is why I suggested that you try going to a hardware store to see if you can get a spring that will work before going through all that.  I can’t promise you will find one, but it is going to be less expensive and less time consuming if you do.  I have walked into Lowe’s, Home Depot and other Hardware stores MANY times over the years with my Precision Dial Calipers in hand to see if they have a spring I can try.  If that doesn’t work, perhaps you know a local Machinist who could get you a spring that may work after shortening it.  If that doesn’t work, then maybe you could take your calipers to a Parts Dealer at a Gun Show and check those springs. 

Or perhaps once you get the precision measurement from a Precision Caliper on the diameter and length of your sear spring, perhaps someone on the forum will have a spring that may work. 

Gus

Offline Artificer

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Re: TC lock tuning?
« Reply #26 on: April 15, 2014, 03:30:10 PM »
Badwolf,

Just had a different thought.  Dixie Gun Works sells replacement TC sear springs listed below:

http://www.dixiegunworks.com/product_info.php?cPath=22_567_608&products_id=12268

This spring most likely won't be any lighter than yours, BUT you may try asking them if they have a spring that will fit and work and will be lighter.  

However, I would still recommend calling the TC customer service and see what they will do before going through anything else. 
Gus
« Last Edit: April 15, 2014, 03:32:41 PM by Artificer »

Offline JBJ

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Re: TC lock tuning?
« Reply #27 on: April 15, 2014, 05:43:05 PM »
How about shortening the sear spring slightly, say 1/4 to 1/2 a coil? This should reduce the compression. If you go this route, as you shorten the spring in small increments go slow and test frequently.
J.B.

Offline LRB

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Re: TC lock tuning?
« Reply #28 on: April 15, 2014, 09:34:23 PM »
  As I recall, 2, and maybe 3 coils can removed in the sear spring, and I would, but those locks have many other problems that need attention also. I've done 6 or 7 of them and they vary in their problems. Often the bridles bind the tumbler and sears if the screws are tightened down as they should be. The contact of sear nose and tumbler notch is usually rough, and often off true. Everything that moves needs polishing. To be at it's best the tumbler needs a sear engagement regulation plate installed as Articifer described earlier. If the sear spring is cut too short, it can be stretched back out, although it would be best to replace it with a weaker spring.  I don't believe T-C ever intended those locks to be used with a plain single trigger. They started that in their later years in order to turn out cheaper versions of their product, and as I see it, no longer cared if they worked well.

chubby

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Re: TC lock tuning?
« Reply #29 on: April 16, 2014, 02:57:20 AM »
LRB, if you go to the vertual museum & library and look up Rifles of unknown makers-(brass)- look up JW???-100822-1, you will see what i mean, Chubby!

Offline LRB

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Re: TC lock tuning?
« Reply #30 on: April 16, 2014, 01:31:45 PM »
  Thanks Chubby. As I said, I've never seen that done before. Very interesting. Thanks again.

Offline Artificer

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Re: TC lock tuning?
« Reply #31 on: April 16, 2014, 01:34:36 PM »
LRB, if you go to the vertual museum & library and look up Rifles of unknown makers-(brass)- look up JW???-100822-1, you will see what i mean, Chubby!

That is downright intriguing!  Took me a few minutes to realize why the end of the screw inside the lock was pointed.  Then I realized as it was screwed in or out moving the area it contacted the sear up or down, it would change position of how far down the sear would be allowed to go into the full cock notch.  As the screw is unscrewed, the rear of the sear goes down further as the point goes towards the outside of the lock.  The farther towards the outside of the lock the point is moved, the further down the rear of the sear, and the more engagement of the sear face up the full cock notch and the heavier the trigger pull would be.  That point makes it adjustable for sear engagement and thus trigger pull weight!  Brilliantly Simple!!

Thanks for pointing this out, Chubby.
Gus



  

Online Bob Roller

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Re: TC lock tuning?
« Reply #32 on: April 16, 2014, 02:55:31 PM »
My friend,the late Bill Cooper had a TC New Englander that had a clunker lock and he asked me if I could do anything to help it.I suggested removing the mechanism and the internal obstructions on the back of the lock plate and make a traditional mechanism with "V" springs. I did this for him and replaced the ugly hammer with one designed by Bill Large in 1972 and it made a big difference in that gun. If you ever encounter a TC New Englander with a fast,positive action lock,it just might be Bill Cooper's old deer rifle. His son took it and a fine Sharps Borchardt to a pawn shop and neither has been seen since.

Bob Roller

Offline Artificer

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Re: TC lock tuning?
« Reply #33 on: April 16, 2014, 06:15:42 PM »
Bob,

That is such a shame the son did not appreciate his father's guns.  Here's hoping they went to someone who truly appreciated them. 
Gus