Tuning set triggers

[B.Barker]

I made the set triggers on the rifle I'm building right now and I'm getting ready to "tune" them. This will work for factory ones also. I know the old timers here already know all this but thought some new builder may be interested. I like my rear trigger to have a tiny bit of wiggle room between it and my lock sear. That way it won't be floppen around when it'snot set. I drill my plate behind the rear trigger and tap it for a 6-32 screw. I also counter sink it so I can run the screw flush with the plate. I make my own screws since I have a lathe in my shop. Once you have everything tapped and made put the triggers in the stock. Run the screw in until the rear trigger it floppy then back it out until you get just the slightest amount of play. Once you get it there pull the cock back to half cock and full cock to make sure the sear engages fully. If the sear doesn't engage the notches on the tumbler then you can tune the lock so it will function. Or find the notch that pushes the sear the lowest point and tune the triggers to the sear setting. I hope I haven't confused you too much. Hopefully the photo's will help.

[B.Barker]

I forgot to add that once you know how long the screw needs to be you then trim it off. That way the head will be flush with the trigger plate. I'll try to take some more photo's as I do my tuning.

[stubshaft]

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[oldtravler61]

   Thanks Brian as I am making a set now. First time for everything.
 Oldtravler

[Cades Cove Fiddler]

  ... sure wish someone would make castings of your trigger set, Brian .... no one makes a trigger set with an authentic Tennessee profile,.....(J. Kibler does, but doesn't sell the triggers separate of his kit),.....

[P.W.Berkuta]

I will add this to the post and that is to Lock-Tite the screw in place once you get the correct position if not the screw can work itself loose and the spring will then apply pressure to the trigger bar and then the sear will not engage the tumbler's full cock notch.

[B.Barker]

Tried to make a video today. However my old brain forgot how my camera worked and I ended up with nothing. I may try again later or just take stills to load up.

[Craig Wilcox]

Really nifty work!  I will be doing my triggers shortly, and really appreciate your "How To".

I am fortunate that I have all sorts of screws from my former work on other-than Longrifles.  Have several sets from Brownell's, and the taps and dies for them.

I second the vote for Locktite!

[Joe Schell]

Very nice work, Brian. What steel do you use for the triggers ?

[B.Barker]

Joe, I use 1084 now since it has plenty of carbon for hardening. However I have used mild steel then case hardened them.

I guess I've been luck my rifle is about seven years old and no lock tite but everything is still tite. Could also be from rust finishing my parts and that may lock things in place. Lock tite isn't a bad idea though.

[Flint62Smoothie]

I will add this to the post and that is to Lock-Tite the screw in place ...

The only thing I can add is to use LOW strength loktite (usually ‘purple’) for the smaller sized screws, not their typical blue product. When I was gunsmithing, I saw more trigger assy screws buggered by loktite, as ‘Bubba’ didn’t apply heat before wrenching the snot out of the screw head ...

[Hank*in*WV]

I use clear nail polish instead of locktite. If it works on old Brit bike, it'll work on anything.

[Stoner creek]

I use clear nail polish instead of locktite. If it works on old Brit bike, it'll work on anything.

I just tried the nail polish trick. Great idea. Thanks Hank!
Unfortunately my bride didn’t have any clear  . Baer Killr now has some sexy pink glitter on her under side.

[B.Barker]

Shouldn't have been so sloppy.

[stubshaft]

Might be a fashion statement?

[B.Barker]

Tried to make a video because it would have showed the process better. However my SD card didn't have enough space and the video was grainy with my camera. So here are some stills of the inside of the lock and the line I marked on the plate for sear position. Also a photo of the triggers held up to the lock to show how they would line up in the stock. Also a photo showing how I measure the height of the screw so I can get the height right after seating the screw completely. 




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[David R. Pennington]

Thanks for posting. My first set of triggers were very similar to yours and I put the screw in as you show. I recently had an issue with mine. Worked fine for years.  Sear not engaging full cock fully. Not sure what changed, humidity? Wood moving? Going to have to revisit it.
If I use “store bought” triggers I usually end up reforging triggers to shape I want.

[Bob Roller]

IF I were to make that style of trigger again,I would make the adjustment screw with a ball head.
The loose fits can be solved by interference fit threads such as a 4x48 thread screwed into a 4x40 hole or threads with
two slightly different angles like a 60 degree US thread into a 55 degree Whitworth thread. I have use the 4x48/4x40
combo for years with no reported problems.
I have made the two bar triggers for decades and the last single release type I made was for a Canadian.

Bob Roller

[David Rase]

The loose fits can be solved by interference fit threads such as a 4x48 thread screwed into a 4x40 hole or threads with
two slightly different angles like a 60 degree US thread into a 55 degree Whitworth thread. I have use the 4x48/4x40
combo for years with no reported problems.

Bob Roller

Bob,
That is a great tidbit of information.  Thanks for sharing your knowledge.  I have done interference fits before by controlling the depth of a taper tape but have not used two different thread pitches.
David

[Bob Roller]

David,
I got that interference thread idea from an OLD article about Marc Birkit who designed
V8* aircraft engines in the early part of the last century.He also was instrumental in the
development of hydraulicly retracted landing gear.
Early overhead valve pushrod operated enginges had a problem with rocker arm screws backing
off and shutting the engine down in flight (a REAL day spoiler).He used two different threads
of 2 different angles slightly out of phase to prevent the back off problem. It worked fine and still
does.He later developed a BIG V12 car engine of over 600CID that out powered every car engine
of that day including the Model J Duesenberg.
Bob Roller

*V8's used in WW1 SPAD fighter planes.

[David R. Pennington]

Well I figured out the sear was touching the wood just a bit in the mortice. A little candle soot revealed the issue. Shaved out a little releif. Been really hot and humid lately. No problem with trigger tuning. While I had the lock out I went ahead and tuned up the lock a little and got everything working real slick. Tried it several cycles. Everything working great. I took out the wooden flint and put a good black English one in to get it ready for next match and cycled a couple times to adjust flint. Frizzen spring broke! Aarrghh! This lock has been constant problems. Thought I finally got it lined out. Well I guess I will make a frizzen spring now. I made a couple main springs for this lock before I finally got one to work right. The original was way too wimpy to get consistant sparks.

[Mikecooper]

I'm glad you posted this,  I have a double set trigger and didn't know why the screw was under the rear spring,  now I know. 

I have a question,  maybe someone will reply here or maybe I should start a new topic,  the rear set trigger bar seems to be too high in the unset position.  I can't cock the lock without first setting the trigger.   Are there any suggestions on how to lower the bar?   I could grind some off the top of the bar but afraid I may have to grind off too much of it. 

Problem solved,  remove the screw under the spring, file off some from the rear trigger surface where the tip of the spring makes contact,  rear trigger moves back and bar goes lower down and no reduction in spring pressure.