Author Topic: How to make a trigger pull heavier?? (Read 3070 times)

Justin Urbantas · « **on:** July 21, 2019, 07:18:28 PM »

So, I have a lock that will trip if it is on full cock, and I open and close the frizzen 4 or 5 times in a row. Makes me nervous that a drop or big bump might set it off if it's cocked. How do you go about making the trigger pull a little heavier? I've never had to make a pull heavier before. Thanks guys.

G_T · « **Reply #1 on:** July 21, 2019, 07:43:10 PM »

Is the problem possibly the sear engagement is too small? If the trigger bar is very slightly too tall, then the sear cannot drop beyond a hair's engagement. That is one possible cause of what you are experiencing. If this is the case, almost no motion of the trigger is required to trip the lock. If there is a little free motion of the trigger before it touches the sear - even if only a very very tiny bit of motion - this is not the problem.

Your symptoms can also occur if wood in the stock is preventing the sear from traveling far enough for good engagement. The contact can be on the sear arm (sure there is some correct term for it but I don't know it) in the relief hole under the lock plate, OR it can be the bottom of the sear side of the sear hitting the inside of the lock mortice. That's an easy one to miss when inletting. One should soot the lock and cycle the lock a few times with it bolted on, to see if there is any contact anywhere you don't want contact. That is one place you absolutely do not want contact.

If the above are not the issue, then it is possible the working edge of the sear is stoned to the wrong angle, or is rounded either through not being of the right hardness or sloppy polishing. If the sear is pretty nicely shaped and smooth, then it could be the sear engagement face on the tumbler which has that issue.

Lastly, one of the simplest is having a sear spring which stops pushing the sear into engagement before full engagement has been achieved. A very slight bending of the sear spring fixes that.

It isn't the trigger spring which you should be worried about here. Tightening that spring will only mask your problem, IMHO.

Gerald

rich pierce · « **Reply #2 on:** July 21, 2019, 08:20:57 PM »

Great information above. Covers 95% of the possibilities. I’d see what force it takes to trip the sear outside the stock. That will differentiate between inletting-related issues and problems with the lock.

Bob Roller · « **Reply #3 on:** July 21, 2019, 08:36:47 PM »

I just finished a lock with a light trigger pull and made for use with set triggers.
It has a shallow full cock angled slightly back and a sear of the same angle to
engage it plus a strong sear spring.* This lock has the externals of the L&R Durs Egg,
and a short,fast stroke of the cock,edge of the flint just off the frizzen at half cock.
It and another one goes to Tenn.I plan to make 3 and the 3rd one will be for sale to
whoever wants it. I will post it when it's ready.
Bob Roller
* Also included is a sear screw of .109 going thru a reamed .1094 hole in the sear
which adds to the stability of this light trigger set up.
One thing more,a lot if not all of the production locks use sear springs that are
rolled sheet metal and I have seen more than one improperly installed
and too weak to begin with.

Justin Urbantas · « **Reply #4 on:** July 21, 2019, 10:34:24 PM »

The lock trips very lightly without being on the gun. My thought is the sear engagement. It is right from the factory, and hasn't been stoned to change anything. Maybe a stiffer sear spring?

David Rase · « **Reply #5 on:** July 21, 2019, 11:02:49 PM »

Quote from: Justin Urbantas on July 21, 2019, 10:34:24 PM

The lock trips very lightly without being on the gun. My thought is the sear engagement. It is right from the factory, and hasn't been stoned to change anything. Maybe a stiffer sear spring?

You need to rely on proper sear engagement over spring strength if you are concerned about safety. It is all a balancing game between mainspring, sear engagement and sear spring. Fortunately you are only working on one lock. I, on the other hand, am in the throws of tuning and balancing a set of double barrel Flintlock shotgun locks to operate in harmony. I expect to spend the better part of one day next week getting everything balanced.
David

WadePatton · « **Reply #6 on:** July 21, 2019, 11:07:40 PM »

The angle of the mating surfaces and the fullness of their engagement should be sufficient to prevent tripping regardless of spring pressure.

Can you get some good-quality pics of the sear engagement?

Justin Urbantas · « **Reply #7 on:** July 22, 2019, 12:43:52 AM »

Well, I came up with an easy fix. I was lucky enough to find a replacement sear in my parts bins. It is much better now. Puts my mind at ease.
For future, is this how you would fix the sear/tumbler engagement?

My thought was to deepen/make a sharper angle on the shelf where the sear nose sits.

David Rase · « **Reply #8 on:** July 22, 2019, 01:35:27 AM »

Here is a photo from a presentation given by Keith Casteel years ago at Dixon's gunmakers fair on lock tuning. This particular flip chart page shows the sear engagement.

rich pierce · « **Reply #9 on:** July 22, 2019, 02:15:21 AM »

Justin, in your drawings with that shape of tumbler notch it would me impossible to trip the trigger. The angle of the full cock notch must be on a radius. A straight line from center of tumbler axle to the edge of the tumbler.

Justin Urbantas · « **Reply #10 on:** July 22, 2019, 02:54:12 AM »

Yeah, I am not good at drawing. (Makes engraving tricky) Thanks Dave, those drawings help. The idea of making a trigger pull lighter seem easy, basically remove metal. Making it heavier without adding metal sounded trickier

Bob Roller · « **Reply #11 on:** July 22, 2019, 03:34:12 AM »

Quote from: Justin Urbantas on July 22, 2019, 02:54:12 AM

Yeah, I am not good at drawing. (Makes engraving tricky) Thanks Dave, those drawings help. The idea of making a trigger pull lighter seem easy, basically remove metal. Making it heavier without adding metal sounded trickier

Contacting the maker of the lock might help.Tinkering with a tumbler if the function
is not fully understood can be a disaster.
If this lock is one of mine I want it back and I will fix it.
Bob Roller

Justin Urbantas · « **Reply #12 on:** July 22, 2019, 06:44:02 AM »

Quote from: Bob Roller on July 22, 2019, 03:34:12 AM

Quote from: Justin Urbantas on July 22, 2019, 02:54:12 AM
Yeah, I am not good at drawing. (Makes engraving tricky) Thanks Dave, those drawings help. The idea of making a trigger pull lighter seem easy, basically remove metal. Making it heavier without adding metal sounded trickier

Contacting the maker of the lock might help.Tinkering with a tumbler if the function
is not fully understood can be a disaster.
If this lock is one of mine I want it back and I will fix it.
Bob Roller

Don't worry Bob. It's not one of yours

D. Taylor Sapergia · « **Reply #13 on:** July 22, 2019, 07:10:00 PM »

Several of the muzzleloading gun builder's books have chapters on sear/tumbler relationship. That would be a good place to start before you set file and saw to your parts. You must understand what and how those relationships function. Your drawing shows me you do not.

The angle of the tip of the sear and the face of the full cock notch have to be stoned to be the same. And that angle is a line drawn through those two surfaces AND THE CENTRE OF THE TUMBLER AXLE. Having achieved that, the amount of engagement (how much steel presses on steel) will determine how heavy or light is the pressure required to trip the sear. The sear spring simply makes the sear ride along the tumbler, and snaps it into the two notches. It doesn't hold the sear in the full cock notch, or prevent it from slipping out. Those mechanics are a function of the angles on the nose of the sear, and the full cock notch of the tumbler.

thecapgunkid · « **Reply #14 on:** July 22, 2019, 08:15:46 PM »

Almost too much great advice here. There is such a thing as too much.

When I had this problem, i had all I could do to work with patience, slowly, on one thing at a time.

I checked the end of the sear against the wood first, because that required the least amount of change if it was the culprit. Some black on the end proved this not to be the problem and I decided NOT to cut the stock in half. I checked the edge of the sear spring against the wood next. There was no tell tale black. I decided NOT to put the rifle through the windshield of my car.

The Happy Hammer was still on the table, tho... I cocked it one more time and became aware that the trigger position was changing, and there was no give in trigger movement when I absent mindedly cocked it.

So I complained to Anne...my wife...who has never fired a flintlock...

I dunno how she figured out that the trigger bar was too high. I went to Dixons and bought two triggers, because, at that time, I was more incompetent than I am now.

When I came back, and heard my Father laughing behind me, I knew I had to slow down and back off. As far as I know, dad remains deceased, but he shows up in my mind's eye every time I screw up with that @#$%& snicker.

He'd probably also there when I do something right, but it doesn't irritate me the way his snicker does.

The third trigger got the gun working well. I dunno how, but it did. My guess is that I found patience somewhere and only filed one or two strokes the three or four times I took it out. So I packed up the other two triggers with a side plate, some bolts and a patchbox spring and brought them as blanket prizes to one of my trail walks. Somebody took it in the second or third pick.

So, now, every time I work on a rifle, I check the trail walk and match schedule...

Moral of the story? If you hear some guy snickering behind you whilst you are having a problerm, send him to Newmanstown where he belongs, keep a good supply of blanket prizes because one man's discard is another man's treasure and listen to you wife when she talks.

Don't shoot yore eye out, kid
The Capgun Kid

Bob Roller · « **Reply #15 on:** July 22, 2019, 09:22:47 PM »

When making a lock,I do not work with prefabricated parts from a foundry.
I do the fabricating myself from 1144 "Stressproof"and 0-1. The 1144 is for the
tumbler and the 0-1 is for the sear and fly.When the tumbler is shaped to proper
profile I use Dykem blue and lay out the angle of the full cock position as defined
by Taylor and this is established by installing the tumbler,bridle and sear and
using the bridle as a stop for the travel of the tumbler I scribe a line for half cock
which I call the first position and then the line for the full cock position by using the
just mentioned bridle.I cut the full cock about .080 deep with a dedicated carbide
end mill that leaves a sharp corner for the sear to engage.The angle of the sear
has been previously established.The .080 depth gives room for the first position
and the depth of that position to hold the sear in position so it will stay there
and will hold against the thrust of the mainspring which I also make and preload.
Holding against the mainspring is the ONLY thing the first position does.It can be
destroyed by a hard pull on the trigger in a single trigger gun or the pounding
of a strong set trigger.I take whatever time is needed for this job and when I
am happy with it I also know the sear won't slip out of place.
I hope this helps because it's all I can contribute to this thread.
Bob Roller

Justin Urbantas · « **Reply #16 on:** July 22, 2019, 09:50:17 PM »

Wow guys, it never ceases to amaze me the depth of knowledge, and helpfulness of you guys on the forum. I'd be the first to admit that lock tuning is the weak part of my gun building skills. I tend to err on the side of safety. The precision of removing such a small amount of metal, but being so important is a bit daunting. The how- to gunbuilding book I have is the old blue spiral bound Dixon book. It doesn't get much into tuning. I really appreciate all the help.

guido · « **Reply #17 on:** July 22, 2019, 10:57:31 PM »

This might sound stupid, it's like an engine that stopped, someone says did you check the gas! Make sure the right screw is in sear spring.. Done that! fixed that.

shortbarrel · « **Reply #18 on:** July 23, 2019, 12:57:12 AM »

I hope you folks read Bob Rollers post above and understand it. He is true master lock maker. I have made and rebuilt many locks for southern SMR rifles. Never used any bought cast part.

helwood · « **Reply #19 on:** July 24, 2019, 01:05:22 AM »

Greetings
These is a sequence of photos of tumblers I made for an Over and Under FruWirth Jaeger I finished last year and totally understand Dave's fun of his Side by Side . The original plan was to use small Siler R&L locks but I couldn't get them to clock correctly so I just decided to start from scratch.

upload pic

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Author Topic: How to make a trigger pull heavier?? (Read 3070 times)