Double Set Triggers

[PlaidSon]

It's storming outside so I'm sitting home tangenting my way through the interwebs and found myself researching DST's. I pretty well understand them but when it comes to double set, double phase a question comes to mind.

We'll assume the rear trigger is the set trigger and the front is the firing trigger.

If the rear trigger isn't set, it would seem to me that it is in a relaxed position on the sear, preventing the sear from engaging the tumbler. That is not the case obviously as one does not have to set the trigger to #### the hammer and the gun can be fired without the rear trigger being set at all. So what prevents the rear trigger from applying pressure to the sear if it hasn't been set?

My guess is the set trigger spring isn't tight enough to hold it up against the sear, but gives the trigger enough inertia to hit the sear then fall back away. Anyone with knowledge on this?

 

[catnthehatt]

The rear trigger spring loads the front to fire it with a lighter pull, but if it is unset, the front trigger may be able to trip the sear anyway, but not always.
Some set triggers will only work if they are set.
Most however, will work set or unset.
The rear trigger does not engage the sear but only loads the front.
Cat

 

[PlaidSon]

The rear trigger does not engage the sear but only loads the front.

This is contradictory to how I understand them. The triggers I am specifically trying to understand are the ones that fire set or unset, "double set, double phase" if you will.

The link to where I was reading:

http://home.insightbb.com/~bspen/triggerterm.html

I wish there was an animation I could watch.

 

[catnthehatt]

"Double set double phase " is exactly what I dud fibre to fire the. Gun unset or set, the front trigger needs to be used .
unset it bears directly o. The sear, set , it gets pulled fie. And spring loaded when the back trigger us pulled the flips up when pulled to hit the sear.
There is an extra lever involved in the double set trigger system .
a single phase trigger is often called a safety trigger
it as sometime use. In small ore match rifles although it d not as poplar as the double phase
I have five different set triggers on guns and only one is a single phase
Cat

 

[PlaidSon]

Ok, now I think we're on the same page. What I don't understand is how the gun can be cocked with the rear trigger flipped up after hitting the sear. Does it rebound away and is no longer in contact with the sear allowing the sear to engage the tumbler again?

 

[catnthehatt]

The rear lever doesn't actually hit the sear, it's the front that does.
The lever for the rear trigger is forward of the sear on a modern rifle or the anvil for the tumbler on a muzzle loader.
Cat

 

[galamb]

This diagram may help a bit. These are Davis triggers, quite popular amongst muzzle loader builders.

In the Double set double lever (top) trigger, if it is "unset" when you pull on the front trigger the (bar) raises and contacts the sear and the gun goes "boom".

If you set the rear trigger, it gets "locked" under spring pressure to the front trigger. When you pull the "front trigger" (with rear set) the "rear" trigger is kicked by the spring and the "rear trigger bar" contacts the sear "momentarily" tripping the lock to fire.

With a Double set single lever the front trigger doesn't really have a bar. So when it's "un-set" there isn't enough there if you pull the front trigger to contact the sear.

When set, just like the first style, the rear trigger bar is locked down under spring pressure and pulling the front trigger releases it. The rear trigger bar then springs up and contacts the sear.

So you CAN trip the sear on a set lock with only the rear trigger, but you would have to "push it forward" to raise the bar to meet the sear (if you get what I'm saying).

This set of "tuning" instructions may also make it a little more clear as to how they function

 

[catnthehatt]

According up Davis their single set trigger single lever cannot be used inset /now I'm confused!!
Cat

 

[PlaidSon]

galamb, those installation instructions cleared everything up. There is play between the rear trigger and sear when unset, as they put it the trigger will wiggle slightly.

 

[galamb]

delete

 

[Ol' Flinter]

galamb, those installation instructions cleared everything up. There is play between the rear trigger and sear when unset, as they put it the trigger will wiggle slightly.

That is correct for a double-set, double-bar trigger. When not set, the rear trigger lays loosely a mm or so below the sear arm so the sear can fully engage into the full or half-#### notches of the tumbler. When cocked, it will be a bit more below the sear so when it is released by pulling the front trigger, it flips up to hit the sear arm and disengage the sear from the full-#### position. The front trigger does not flip up at all. Properly adjusted, neither trigger will fire from the half-#### position. With the rear trigger not cocked, the front trigger is pulled and behaves like a simple trigger in that the blade rotates up against light spring pressure to release the sear. The light spring pressure forces the front trigger to capture the rear trigger when the latter is set against it's own much stronger spring pressure.