Thanks for all the input. I think I now understand how to make the set trigger. Dan, your pictures were a big help. In "GGC" Alexander write that front trigger pivot point must be 1/16" to the rear of the hook . You say the pivot point must be in line with the hook .
According to Alexander your design is unsafely unstable. According to you Alexanders design makes the trigger pull to heavy. A bit confusing for a newbee.
On my first attempt, I'll but the pivot point 1/32" ahead of the hook and keep the backlash adjustment screw. I'll lower the trigger pivot points 2mm . I hope to start on the brass mock-up this week end (if I can get time off from my wife's house projects. We are redoing the kitchen).
I'll post pictures when done.
Best regards
Rolf
Publishing a book does not make one a gunsmith. It just makes one a published author.
A short rear trigger will not stay set without an increasingly heavy front trigger spring as the rear trigger's tip get farther and farther forward of the trigger pin. This will result in the trigger having to be adjusted for excess engagement in many cases. This coupled with a heavy spring can result in a set trigger with a pull as heavy as a well done plain trigger.
A long rear trigger tends to stay set and will give a higher trigger pull than the ideal.
The ideal....
Ideally the trigger should stay set with NO front trigger spring but few do. But fire at a touch if adjusted light.
To do this requires careful attention to rear trigger length AND the angles that the engagement surfaces have. They should be angled slightly so that they tend to stay set. If over done this will result in a very heavy trigger pull. If it is done right the trigger will stay set with very little or no front spring pressure as they should. Using a long trigger will almost do this as well and might be why Alexander recommends this.
Just as an informational thing the Rollers triggers I pictured? They have a heavy front trigger spring and will BARELY stay set without it set for a reasonably right break. If I depress the front spring and it rubs the side of the trigger the triggers fires. If not it stays set. Just like it should
http://s72.photobucket.com/albums/i199/DPhariss/Video%201/?action=view¤t=Bob Roller trigger.mp4
The Roller trigger shown here can be adjusted to 1.5 ounces but must be set to 4.5 or more ounces to remain set with the front trigger spring depressed. Set at about 4 ounces the triggers will fire if the spring is depressed. Set to 6-7 ounces the trigger fires at an average of 2.2 ounces with the front trigger spring depressed by my Lyman digital pull gauge. So the spring, which is fairly heavy, adds about 2-3 ounces to the trigger pull. How much tension is applied by the mainspring will effect the trigger pull the 5-6 ounce pull is with sufficient mainspring pressure based on my experience.
So I suppose I could lightly stone some surfaces maybe lighten the spring but really this is a very good trigger as is being 1973 build date "new old stock" triggers.
A set trigger should be
able to be set very light. Even if the shooter has no desire for a very light touch. Nor should it be such as to be able to be adjusted back to a very heavy pull. Its not the purpose of the set trigger. People that want 3 pound triggers, for example, should use a plain trigger in the first place.
The multi lever triggers found on some Schuetzen rifles would fire if the rifle were turned muzzle up.
Some had a false trigger, a finger rest if you will, to place the trigger finger on and a thin wire that was the actual firing trigger which the shooter would break with a slight twitch of the finger or increase of pressure on the "finger rest" so as to touch the wire. These triggers have 1 or more levers that isolate the front trigger from the spring pressure of the rear trigger.
A quick look at "Single Shot Rifles and Actions" by Frank de Hass shows and describes a 4 lever at pgs 237- 238
This was the whole idea of a set trigger, a trigger that would fire at a touch or slight pressure.
2-3 ounces while doable is not practical for most shooters and uses. So most set triggers are heavier than this and really should be. For a hunting rifle the 6-8 ounce trigger is probably best and its hard to get a good set trigger under this with out a lot of travel in the front trigger.
The trigger adjustment screw needs to be locked lightly to prevent its moving in normal use and lightening the trigger unexpectedly. Light staking of the threads or a drop of soft stock finish will usually do this.
People who built ML parts or assemble rifles need to understand the way things are supposed to be. Just as a lock should stay on full clock with no sear spring pressure so should trigger stay set with no front trigger spring if everything is in perfect balance.
In experimenting and looking at original guns, military guns, the Sharps, Ballards and Winchesters etc, the good quality guns, had good locks and if set trigger equipped . The angles were right and everything worked as it was supposed to. They were designed and put together by skilled workers who understood the workings of locks and triggers. As a result even a military sized lock like the Sharps can be tuned to a very light trigger, I had a match rifle with an 8 ounce plain trigger. It would stand my "3 whacks with a mallet" test unless struck on the hammer screw. The mallet was a light rawhide or small dead blow that I used for fitting actions.
So either lock or set trigger require a basic understanding of the way the parts interact and care in making the parts work together as they should.
I would also point out that people who make MLs often have different ideas and ways of doing things.
But the discussion of triggers above stems from examination of original triggers and experimentation on my own. The Hawken triggers made by Bob Roller (I have 2 sets I found at gunshow) are usable as purchased and are made as I would now recommend though made before I became adept at lock and trigger making so it was apparently commonly known at that time.
If I had to choose between the advice of "GGC" and how Bob Roller made his triggers I will go with Roller.
I learned set triggers while working as the custom shop at Shiloh. I learned that to make a really good trigger the end of the rear trigger must align with the centerline of the front trigger pin.
Make set triggers with a 1/16 too short rear trigger and it will be impossible to keep it set without a strong front trigger springs and/or angles that "trap" the front and rear triggers in place. Neither is the way to make a good set trigger.
Its easy to fix a too long rear trigger, so long as the front trigger is made properly then shortening the rear trigger will allow fixing the problem.
Dan
Edited I hope I got all the errors out
