AmericanLongRifles Forums
General discussion => Gun Building => Topic started by: Tim Ault on February 04, 2014, 02:26:52 AM
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I pounded out my home made trigger this weekend ,I plan on the height of pin placement at the sear screw ,Now on mine the pad of the trigger is approx a 1/4 inch to the rear of the front of the bar . I have done a search and seems between 3/8 to 1/2 seems to be whats recommended ,Now is that distance from the pad of the trigger or the actual pin/pivot location. Also what good or bad will happen if I increase the distance further forward to say 5/8 the, Trigger will be pinned to the plate if it make a difference.
Thanks,Tim
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I pin mine at or just below the level of the bottom of the sear and the sear contacts the trigger bar about 3/8" to the rear of the pivot pin. Others do it different but experimentation is good.
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Here is a rough "artists conception" of the tutorial in the Gunsmith of Grenville County which is quite detailed on trigger placement.
Each of the three placements (or any point in between) will work, it is the weight of the pull which will change along with the amount of travel.
(https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Fi760.photobucket.com%2Falbums%2Fxx243%2Fgalamb2%2Ftriggersear_zpsebd91aca.jpg&hash=bd7de6d5cfb9f5f1ba2fcc7218f64913e1a76327)
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I was taught to place my pivot pin so the trigger plate rotates at the same angle as the sear to reduce friction. I hope that makes sense.
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I learned the same way as Thom, to pin the trigger on the same "line" as the pivot of the sear to the bottom of the sear bar. At minimum I keep my trigger pin about 3/8" (on a pistol) to 1/2" on a rifle. Any further and you'll have excessive trigger weight, any less and you'll have excessive creep and a spongy trigger pull. Keep in mind that trigger pinning is only half the issue; the other half is lock tuning, but that's a different subject altogether.
-Eric
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(https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Fi760.photobucket.com%2Falbums%2Fxx243%2Fgalamb2%2Ftriggersear_zpsebd91aca.jpg&hash=bd7de6d5cfb9f5f1ba2fcc7218f64913e1a76327)
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Left: shortest pull, most force required.
Middle probably best scenario.
Right: longest trigger pull, most creep, and lightest feel.
In any case, the lock needs to be worked over to reduce trigger pull and creep.
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I personally like the placement between the two right diagrams. Very light & it feels sweet. I prefer my pin slightly higher & approximately 1/4" (no more than) 3/8" from the sear.
Darrin
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To throw a complication into the mix - how do these measurements change when the length of the trigger changes? I have been pondering this recently, as the original my current build is following has a rather long trigger, almost long enough to use two fingers like a Northwest Gun. I had planned to pin it at 3/8" (my other rifle is pinned at 1/4" and has too much creep for my taste), but I am wondering if it might be better to pin it at 1/2" or even a bit more in light of all the extra leverage - and long travel - that long trigger is going to have.
I note that the original is also pinned pretty far forward, and copying that would help improve the architecture by shortening the stock for a given pull length.
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I just built an English Sporting Rifle and the sear contacted about .330" ( a little over 5/16") behind the hinge pin. I had Track's York County trigger assembly with a a blade about 1 1/8" long below the pin. The weight of pull was more than 5 pounds, the limit of my RCBS trigger gauge. I replaced the blade with Track's 3-curl trigger, #TR-G-260-T, about 1 5/8" long, and moved the hinge pin to a little closer to the sear. Now the pull is a little over 3 pounds. I like a 1/4" distance and a pull of a bit less than 3 pounds.
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The pressure needed to break the sear from the notch is the key.
Farther from the sear makes for a crisper trigger pull with no creep.
Too close lots of creep harder to shoot well.
Even 3/4" will work well if the lock its right and will be far better than 1/4" with a lot of creep. My English Sporting rifle is this way. Much farther than I wanted using cast trigger bar. Had to have the tang screw in the right place, but the pull is very shootable and I suspect about 4-5 pounds, breaks clean.
But any trigger work with a plain trigger needs to stand a dead blow mallet test of three whacks.
I had a Sharps (big military size lock internals) with a 1/2 pound pull that would stand three whacks with a light rawhide or plastic dead blow anywhere on the gun but the hammer screw. These trigger have the sear probably 1/2" from the pivot and its not very high either.
Dan
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I built a Leman in the Green River Rifle Works shop in 1978 and we followed their blueprint which shows the sear bar 5/8" behind the trigger hinge pin. Mine is probably 1/2" and the pull is heavier than I like. I have no trouble with creep in my 1/4" spacing. Just dry fired my English Sporting Rifle a half dozen times, and no creep.
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I hate to comment on a post like this, because it seems everybody has their opinion. But I of course will... Earlier in my gun building, I tended to pin relatively close to the sear. Probably around 3/8" was typical. I gradually started pushing this upward and now it's around 9/16" - 5/8". Most all of the originals I've studied have had distances in this range or greater. Also, in talking with Mark Silver a while back he talked about his preference being in this range as well. In practice, I'm very happy with how the triggers feel. A very well tuned lock will still allow for a light pull with distances such as this. The nice thing is that there is very little creep with this type a set-up. Like I said, I've tried a lot of arrangements and am happiest with this.
Now with all this said, Lock work can compensate for a particular trigger geometry. If the pin to sear distance is relatively small, you can push the full cock notch a little smaller to compensate. With greater distances, the need is to work the lock such that the required pull is diminished. It's good to have an idea of what you are doing and some ability with some of this work though, as safety is important.
Jim
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I have used single triggers on all of my barn guns. I have found that the best trigger (for me) is by having it pinned slightly
under 1/2" in front of the sear bar. If you pin the trigger over 1/2"in front of the sear it will pull harder, the greater the
distance, the harder the pull. Conversely, if you pin it closer to the sear if will pull easier, but will have more movement.
Don
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Thank you gentlemen for all the input and ideas .
Thanks , Tim
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Below is an extremely crude drawing of how Jim Chambers instructed me to pin a single trigger. I did my trigger on my Lancaster this way, and it's really a wonderful trigger... that Jim guy knows what he's talking about! ;)
(https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Ffarm6.staticflickr.com%2F5542%2F12385566403_8cec6faa8d_c.jpg&hash=8f56d406538b3c0d5fc55bfb75a1d6cf034b5060)
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Great post! I just finished a Chambers Lancaster kit for a NRA banquet item. The pin is high and forward. Although the trigger pull is light it has sponginess to it I could not understand.
thanks for this post again!
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Below is an extremely crude drawing of how Jim Chambers instructed me to pin a single trigger. I did my trigger on my Lancaster this way, and it's really a wonderful trigger... that Jim guy knows what he's talking about! ;)
(https://americanlongrifles.org/forum/proxy.php?request=http%3A%2F%2Ffarm6.staticflickr.com%2F5542%2F12385566403_8cec6faa8d_c.jpg&hash=8f56d406538b3c0d5fc55bfb75a1d6cf034b5060)
Over the years, I've seen a couple of duelling pistols set up that way. I really like the results, and use it when I can.