Double set triggers that only do single set

[scottmc]

I just finished inletting my triggers today and after grinding both down substantially so they dont impede the sear, it turns out that I can only cock to full cock with the trigger set first.  The tension of the set trigger spring I guess exceeds that of the sear spring so the sear won't engage if the triggers are not set first.  Is this common from time to time?

[RichG]

you still have interference. adjust set trigger to a shoot able let off.  Is the sear in the middle of the trigger levers? Make sure no wood is interfering with the sear spring. If the sear is resting on the set trigger bar and you've already ground down the lever, you might have to bend or grind the sear. Or if your OK with it, just set the trigger first.

[Mike Lyons]

Will it engage at half cock?  What’s it doing when you try to engage them without the triggers set?  Is it not catching?  I’m no expert but I couldn’t get the cock to engage half cock or full cock until I made clearance between the sear and trigger. I took a lot off the triggers to get them adjusted to work using inletting black to give me a reference.  Like I said,  let an expert chime in. 

[Stophel]

The area to look at is the front end of the spring where it bears on the rear trigger.   

[Ross Dillion]

Track of the Wolf has a good tutorial on set trigger installation. You shouldn’t have to bend your sear bar. The trigger bar should be under spring tension only through 2/3 of its movement. The last 1/3 is inertia. This is what trips the sear. You should have free play between trigger bar and sear bar while hammer is fully down/uncocked.

[scottmc]

The cock engages at halfcock but not at full.  I used a Cochran lock and the sear really drops from rest to full cock so I'm guessing that is the issue.  The tension that the set trigger spring exerts o. The set trigger makes it pop up too far.

[Bill Raby]

Maybe this will help. The trigger stuff starts about half way through.

[Ross Dillion]

Good advice to consult a building video. It’s tough to explain trigger installation.

[Dave Tercek]

Great information for builders. I myself am just casual shooter and hunter.
I'm still looking for an explanation as to the purpose of the set trigger. Why not just have a single trigger ? I have some modern hammer shotguns that work fine without set triggers. Is it to allow the front trigger to be set very light ? Safety issue ? Please pardon my ignorance, I have tried to find the reason on my own. I'm just not sure.
Thanks,  Dave

[B.Barker]

Set triggers can be "fixed" so they will let the rifle to be cocked without setting the triggers first. However your problem can be fixed by lock work. The sear doesn't set at the same place for each position of the tumbler. On a well tuned lock the sear will return to the same place at rest, half cock and full cock. From your explanation it sounds like you need to do some work on the tumbler notches or maybe just one notch. You must be careful doing the work and if your not sure get someone that knows how to do it. I "tune" my set triggers for the rifle I'm building. Jason Gatliff has a video of Frank House modifying and tuning Davis set triggers. It's worth getting if you plan on using set triggers on a lot of builds.

[Bill Raby]

Great information for builders. I myself am just casual shooter and hunter.
I'm still looking for an explanation as to the purpose of the set trigger. Why not just have a single trigger ? I have some modern hammer shotguns that work fine without set triggers. Is it to allow the front trigger to be set very light ? Safety issue ? Please pardon my ignorance, I have tried to find the reason on my own. I'm just not sure.
Thanks,  Dave

With the front trigger you have a normal trigger pull. With the trigger set, it reduces the trigger pull down to a couple of ounces. On a modern rifle with no set trigger everyone always wants a light trigger pull. Makes it great for all around shooting. On a rifle with set trigger I prefer to have the normal trigger pull a bit heavier than what you would have for a modern rifle. Makes it good for taking a quick shot or shooting with gloves, etc. I will set the trigger for a slow, well aimed shot or shooting from a rest. You get a super light trigger like the modern target rifles.

[Dave Tercek]

Bill, Thanks for the reply
That is the way my Thompson Center rifles works. The rifles I have now are different. The front trigger does not engage until the rear set trigger is pulled. It is always a two step procedure to fire the gun.
Dave

[Bob Roller]

I have wondered about set triggers myself and I have made a LOT of them.
To use them on a gun that has to have the trigger set before it can be cocked
is dangerous but probably,back in the "day" nobody worried or thought of safety.
Some of the REALLY high class European set triggers are works of mechanical art
and were made by watchmakers.Legend says some of them can be fired by the
weight of a shadow.The pistol shooters liked the ones that were made in Suhl in
Germany.They were called Suhlerstecher--Zoo lur stasher and when the finger
touched the trigger,the shot was fired and the trigger did not move,only the
release bar that strikes the sear moved.I made 6 of these for a man in Koln
40+ years ago for pistols.
   Getting back to the American long rifle and set triggers,I never did see a reason
for them on rifles that had no really good sights and the best shooting I ever did
with a muzzle loader was with a Whitworth with an Alex Henry barrel and a VERY
fine,tuned Brazier 4 pin lock and a single trigger.I shouldn't be too critical of the set
triggers because I make them almost every day and the sell easily here on an
affluent forum that does NOT gripe about the price.

Bob Roller

[scottmc]

I am only using set triggers on this rifle since it's a tennessee school rifle of my creation, mixing various attributes I like from various builders  from the days of yore.  Since you very rarely see one without set triggers, I figured I'd use them on this one.

Brian, thanks for the information on the lock tuning.  I didnt realize the tuning could effect how the sear moves.  It was tuned by Brad Emig when I got the lock but i may see if he can do anything with the sear movement.  If he can, it might work fine since it fully engages at halfcock without setting first.

I have not watched video yet but will today to see if I'm missing something.  I never thought installing them would be much of an issue but I learned different.  Single triggers are a piece of cake comparatively speaking.
Y ou can see in the picture how thin I have set trigger ground down.  I'm afraid to go any further at this point.  It's only 1/16th thick where the sear rests.

[D. Taylor Sapergia]

When a rifle is very thin vertically through the lock/triggers area, it is sometimes necessary to do some work on the triggers to let the hammer trigger relax a little more to clear the sear arm.  Look at it this way:  if you remove the mainspring from the triggers, the back trigger will relax and fall well clear of the sear, correct?  But you need the mainspring to make the back trigger kick up and trip the sear.  I test the action of the triggers by holding a screw driver lightly by the end of the handle over but not touching the hammer trigger.  When I fire the triggers, I watch to see how hard the hammer trigger strikes the screw driver.
So your task is to file/grind the engagement area of the mainspring and the hammer trigger.  Filing a tiny bit off the end of the contact area of the mainspring, for example, will allow the trigger to relax a little bit, and the bar of the trigger will drop down just a bit.  Filing a little more off will allow the trigger to relax still further, and eventually, it'll clear the sear arm, and you can cycle the lock without setting the triggers.  This can also be accomplished by installing an adjustment screw through the plate to lift the mainspring off the cocking trigger.  But there still needs to be significant pressure from the mainspring on that trigger, so it is a balancing act.  The mainspring, with good pressure on the trigger, will allow that trigger to have a very short time when the mainspring is actually pressing on it, and the rest of the time, the trigger is just floating, and resting clear of the sear arm.
You can alternatively, grind some of the trigger's seat away to allow the mainspring to clear the trigger.  The mainspring, in a nice set of triggers, comes to rest against the trigger plate, and allows the trigger to rest clear of the sear arm.  If the hammer or rear trigger is under full tension from the mainspring and there is no floating of the trigger, it will interfere with the sear, and you have the issue you're dealing with.  I've never had to remove that much metal from the hammer trigger...I adjust the contact of the spring and trigger.
I hope I've explained it adequately.

[Scota4570]

I am dealing with this issue on my current build.  On mine the rear trigger mainspring is holding it's lever up when at rest.  That is causing it to depress the sear on the lock.   I still have lots of slack on the front trigger.  I do not want to grind the set trigger  bar because it is thin already.  Bending the sear bar on the lock would work but it  would make the front trigger slack even more excessive.  What to do in my case?

Adding a set screw to limit the distance the set trigger spring pushes the sear will fix it.  Momentum is sufficient to trip the locks's sear.  By adding the screw shown in the picture I will get snappy action and not interfere with the lock function.  Yes I could back off the spring that powers the set trigger but the action of the set mechanism looses strength. 

[scottmc]

Taylor, I understand fully what u are saying and it makes perfect sense.  It is exactly what is occurring with my situation.  I will try what u recommended and see how it goes.  Worst case is I screw up the trigger spring and have to get another and try again.  Thanks for your insight on this!!!

[Stophel]

Holy cow, you have ground off way too much of that trigger.

Where the spring bears on the rear trigger is where it needs to be cut down, so that when, at rest, the trigger bar isn't stickin' so high up.

[scottmc]

Stophel, I agree☹.  But believe it or not, I needed to lower it this much just give enough clearance for the triggers to be set in and clear the sear (without the trigger spring installed).  Do you think it will not hold up over time?  Perhaps I should have planned the layout better when we were designing the blank.

[Bob Roller]

I am dealing with this issue on my current build.  On mine the rear trigger mainspring is holding it's lever up when at rest.  That is causing it to depress the sear on the lock.   I still have lots of slack on the front trigger.  I do not want to grind the set trigger  bar because it is thin already.  Bending the sear bar on the lock would work but it  would make the front trigger slack even more excessive.  What to do in my case?

Adding a set screw to limit the distance the set trigger spring pushes the sear will fix it.  Momentum is sufficient to trip the locks's sear.  By adding the screw shown in the picture I will get snappy action and not interfere with the lock function.  Yes I could back off the spring that powers the set trigger but the action of the set mechanism looses strength. 

I would make a new mainspring for that poorly designed trigger system.
A lock with an operating "fly' should have a set trigger that when released will
strike the sear and then drop back down.This is another case of mismatched parts
and a problem caused by them.A two lever trigger should not hold the sear up
after the gun is fired and neither should the "must be set"types,single release.
Taylor's recent post on the pistol grip Hawken shows a well thought out/laid out
project that turned out extremely well.

Bob Roller

[Stophel]

Stophel, I agree☹.  But believe it or not, I needed to lower it this much just give enough clearance for the triggers to be set in and clear the sear (without the trigger spring installed).  Do you think it will not hold up over time?  Perhaps I should have planned the layout better when we were designing the blank.

It's so thin, it's scary.

If it were me, I'd get another rear trigger, fit it in place, and work down the bearing surface on the rear of the trigger, where the spring goes (and perhaps the tip of the spring too, depending upon how everything sits and works together in the plate).  You'll remove probably half as much material, or even less, than you had to remove from the sear bar.  This will swing that set trigger way down where it should be.  It can go down quite a bit, so long as it's not beginning to engage the front trigger.  Of course, it would need to then be hardened and tempered.   I'd bet that this would be sufficient to clear your sear without having to grind the sear bar down to nothin'.   

[Ross Dillion]

Have to agree with Mr Roller on this. I don’t know what’s going on with that mainspring but these triggers are gonna be near impossible to properly install with that spring. 

[greybeard]

Stophel, I agree☹.  But believe it or not, I needed to lower it this much just give enough clearance for the triggers to be set in and clear the sear (without the trigger spring installed).  Do you think it will not hold up over time?  Perhaps I should have planned the layout better when we were designing the blank.

Do at stofell says.   Bob

If it were me, I'd get another rear trigger, fit it in place, and work down the bearing surface on the rear of the trigger, where the spring goes (and perhaps the tip of the spring too, depending upon how everything sits and works together in the plate).  You'll remove probably half as much material, or even less, than you had to remove from the sear bar.  This will swing that set trigger way down where it should be.  It can go down quite a bit, so long as it's not beginning to engage the front trigger.  Of course, it would need to then be hardened and tempered.   I'd bet that this would be sufficient to clear your sear without having to grind the sear bar down to nothin'.   

[scottmc]

I surprisingly corrected the problem yesterday after talking with Brad Emig on the phone.  Was going to grind a little at a time off the shoe of the spring but checked the screw on the spring and it was cranked down tight.  I turned it out a half revolution at a time and after one full turn, it lessened the tension enough that the sear engages the full cock notch without issue.  I Cycled it many times with no problem.  Moved on to trigger guard installation and will complete that today.  Thanks for all of your insights and suggestions as it helped me to narrow down the culprit.