Help with a single set trigger

[Cory Joe Stewart]

Hello everyone,

I have a question about single set triggers.  The images who my trigger in the closed position and the open position.  Where do I try and position the trigger set in relation to the sear bar?  Should it touch when open??




Coryjoe

[Dave B]

I have yet to use one of these types of triggers but I have several sets of originals and they have a dent in the release bar where they contact the sear of the lock. They are both slightly a head of the adjustment screw. Here is on of the triggers mentioned

[Bob Roller]

That is not a good quality trigger and it is not single set.The single set trigger
is only one trigger with a set/release mechanism which can be simple or of a
very sophisticated European type.That trigger shown in the picture has a terrible
over travel and if installed in a rifle,it would have to be carried with the trigger in the set position
or would require setting befor the lock could be cocked. If the lock you have has a half cock and
"fly"the rear trigger mainspring should be reduced in strength so it can flip up and fire the lock
and then drop down so the lock can be recocked without setting the trigger.

Bob Roller

[bgf]

That is not a good quality trigger and it is not single set.The single set trigger
is only one trigger with a set/release mechanism which can be simple or of a
very sophisticated European type.That trigger shown in the picture has a terrible
over travel and if installed in a rifle,it would have to be carried with the trigger in the set position
or would require setting befor the lock could be cocked. If the lock you have has a half cock and
"fly"the rear trigger mainspring should be reduced in strength so it can flip up and fire the lock
and then drop down so the lock can be recocked without setting the trigger.

Bob Roller

I think it is what is called a double set, single lever trigger.  I.e. it does not fire unset and requires setting the trigger before the lock is cocked (just as you say).  I believe the one advantage it does have is that the trigger spring exerts force on the sear during firing and so does not require a fly in the lock.  Probably made because it is a little simpler than a real double set double lever trigger or because some locks do/did not have fly.  I wouldn't prefer one for any case I can think of !

On the original question, I think they need to be positioned as DaveB says (adj. screw roughly under sear bar) and the trigger bar should exert a bit of pressure on the sear when trigger is unset.  

[Dr. Tim-Boone]

Double set, Single action trigger

Here is a single set, double action trigger, you push the trigger forward to set it. It will fire from either set or unset position;



I inlet the trigger and file the trigger bar so that it just touches the sear bar when unset. that way it doesn't flop around. Seems to work well. I am amazed at how little snap it takes to set off even a round faced English lock.

[Dphariss]

Triggers need to be adjusted to reduce the "rest" position of the rear trigger so it does not contact the sear. Adjusting the mainspring contact on the rear trigger is best. The mainspring should stop on the trigger plate so that the rear trigger only touches the sear due to inertia imparted by the spring.
If it touches the sear when unset there is a potential for an unsafe condition.
I.E. an accidental discharge.
Dan

[bgf]

Triggers need to be adjusted to reduce the "rest" position of the rear trigger so it does not contact the sear. Adjusting the mainspring contact on the rear trigger is best. The mainspring should stop on the trigger plate so that the rear trigger only touches the sear due to inertia imparted by the spring.
If it touches the sear when unset there is a potential for an unsafe condition.
I.E. an accidental discharge.
Dan

Dan,
I should have added a qualification about the pressure on the sear when unset -- that is only if the lock does not have a fly.  It isn't a great setup.  IF the lock has a fly, what you say is true.  If the lock has half-cock but no fly, the trigger needs to push on the sear when it is unset, so that it keeps the sear free of the half-cock notch when fired.  If the lock he is using has a fly, he could also add a backlash adjustment to limit travel of the mainspring and trigger bar.

[Cory Joe Stewart]

Sorry I got the terminology wrong, I asked about that a couple of weeks ago.  I know how the trigger works in firing, what I need help with is positioning in the stock.  The photos of the original are very helpful.  

Coryjoe

[Rolf]

Hello everyone,

I have a question about single set triggers.  The images who my trigger in the closed position and the open position.  Where do I try and position the trigger set in relation to the sear bar?  Should it touch when open??

Coryjoe

This is the same type of trigger I've made for the long barreled pistols I'm building. If I understand correctly, it is called a "singel phase double settrigger.". I wrote a tutorial on building them
http://americanlongrifles.org/forum/index.php?topic=21961.0

The front trigger fires the gun, the rear trigger cocks the trigger mechanism. The front trigger should be placed the same distance from the sear as you would place a normal trigger. Otherwise you risk lengthening the trigger pull on the rifle.

The rear triggerblade should never press on the sear. Not when the trigger is cocked and not after it's fired. The rear triggerblade releases the sear the by "slapping"it, and then falling down to neutral position.

Look at the trigger in the tutorial. The rear screw adjusts the travel of the main spring and therefore also the travel of the rear trigger blade. The front screw adjusts the engagement between the front and rear trigger.

1.I install the trigger in the stock in the set position and file the height of the blade so it barely touches the sear.

2 Next I fire the trigger. The rear triggerblade will now lock the sear in the fired postion and it will not be possible to cock the lock.

3. The rear screw adjusts the travel of the triggers main spring. I screw in this screw, until the rear triggerblad no longer presses against the sear.

The trigger is now installed and adjusted.

Best regards
Rolf