Questions regarding making a singel set trigger for a pistol.

[Rolf]

I'm in the planing stage for a singel set trigger for a long barreled pistol. I have Pryor MT.Bill 's booklet on triggers. and have been looking at the measurements suggested in the plans. The overall length is 4" and i need to shorten it to max 3". The biggest challenge is shortening the length  behind the shear.  Bill's plan is 2.8125" from the rear end to the pivot point of the front trigger. I have to reduce this to 1.5" - 2.0".

1. The length between the triggers pivot points is 0.8125"(13/16") . How much is it safe to reduce this?
2. The length of the rear spring is 1.5625". How short can I make the spring?
3. Does anyone have measurment on a singel set trigger for a pistol?

Best regards

Rolf

[Dphariss]

I'm in the planing stage for a singel set trigger for a long barreled pistol. I have Pryor MT.Bill 's booklet on triggers. and have been looking at the measurements suggested in the plans. The overall length is 4" and i need to shorten it to max 3". The biggest challenge is shortening the length  behind the shear.  Bill's plan is 2.8125" from the rear end to the pivot point of the front trigger. I have to reduce this to 1.5" - 2.0".

1. The length between the triggers pivot points is 0.8125"(13/16") . How much is it safe to reduce this?
2. The length of the rear spring is 1.5625". How short can I make the spring?
3. Does anyone have measurment on a singel set trigger for a pistol?

Best regards

Rolf

These things can seldom be made from a plan without modification to fit the intended firearm.
This a SS trigger for a pistol made using the drawing from Nigel George's "English Guns and Rifles".
But modified to fit into the pistol.
This is a very good trigger.



In making a set trigger the sear surfaces of the trigger must be centered over the pin.





When it was complete the front trigger spring was in a mortice in th plate under the mainspring.
I should have taken more photos before final assembly.

This is the same design used in a rifle with more vertical clearance. But I put the mainspring in front




The spring is made so that it does not put pressure on parts with the trigger in this position





The spring is made so that it does not put pressure on parts with the trigger in this position so the lock be cocked while the trigger is unset.
The pistol trigger has a stop on the plate to accomplish the same thing.


I removed the trigger curl soon after I tried it in the rifle. Made setting  the trigger painful.
This rifle was originally made with a plain trigger and I welded  lump on the plate and then filed it to shape for the rear pin.


This drawing is for DSTs but the pin sear relationship is the same for the SS trigger.

Dan

[Rolf]

Thanks for the input Dan. Impressive work!!! But not the type of trigger I want to make. I think I've must have got the trigger type names wrong again.

The pistol I'm making is inspired by this long barreled pistol by Hershel House. It has double triggers where the rear trigger has to be set first to before the the front trigger can fire. The front trigger alone cannot fire the gun.

Books I have read warn that if the rear trigger arm to short, it won't stay set. But what is to short?? No minimum length is specified.
They also warn against making the spring to short, but no minimum length is suggested. How short can the spring be??






Best regards

Rolf

[Dave B]

Rolft,
The simple set trigger is what you are referring to.  You should not have any problem shorting up the parts a little with not but some minor bending of the spring to get best function. Your skills are up for it. Here is the Kit sold by TOW. Moving the screw hole for the main spring up by a half inch will gain you some space. bending the trigger plate  to match the contour of the pistol being done first then observe where the spring needs to be located to get the best force on the trigger. You may need to  bend the spring to get best engagement. I bet that you may not need to bend it much but shortening may be in order. You will need to install an over travel screw to keep the main spring from preventing the cocking of the pistols lock. You can see it under the main spring in the assembled trigger. Taking of the bar extension just past the base of the main spring to the area just in front of the  front trigger return spring where the tang bolt screws in is just at 4" on this trigger.  I really thing it will work just fine at 4" if you tweek the plate just a mite.
http://img.photobucket.com/albums/v648/DaveB44/tr-dst-1_1.jpg
http://img.photobucket.com/albums/v648/DaveB44/tr-dst-1k_1.jpg