Finding the right Sear

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Finding the right Sear

Post by Tim:H11 on Fri Nov 27, 2015 7:10 pm

So I've been studying, testing and learning on how to do trigger work on a 1911. I know, I know .... Send it to someone who knows what they're doing right? But I really want to learn how to do this sort of thing and do it right. Call it tinker-itis if you want but I'd really like to be able to do excellent trigger work for people someday. 

I've mentioned here before that I did get my trigger to have a smooth and clean pull, crisp and clean break, no creep to speak of, and the over travel screw is set perfectly. But I have hammer follow ONLY when using the slide stop as a slide release. This is on a loaded magazine (snap caps not live ammo). And to be clear the hammer follows the slide as the slide goes into battery but the hammer stops at the half cocked position. 

Now if a loaded magazine is inserted into the gun while the slide is in the locked back position, as if I just emptied one mag and exchanged it for a loaded one, and I pulled the slide to the rear and let it go to chamber the first round instead of using the slide stop as a slide release like explained above, then I have no issues. 

Some of the information I've gathered on trigger work was from the article on Brownell's website about a 2 1/2 pound trigger pull. (Link for it below)  In that article it talks about a common problem being hammer follow. It is explained as having too short of a sear and so the sear can not fully and/or properly engage the hammer hooks. The reason the sear is too short is because the pin holes for the hammer and sear in the frame are slightly too far apart it claims. This keeps the sear too far away from the hammer and any work done to the sear I imagine makes this problem more evident. The solution that was talked about was getting a longer sear or a sear with a longer nose. 

Since I have this problem it talks about (not knowing if it's truely due to the sear and hammer pin holes being too far apart or not) I'd like to experiment with trying a new sear but one that is in fact longer. However - and yes here comes the big question and the reason for my post - how do I know if I'm ordering a standard dimension sear, or one that is longer? Are there different sizes or lengths? What Sears do you commonly use or see or hear of pistol smiths using? 

2 1/2 pound trigger - http://www.brownells.com/aspx/learn/learndetail.aspx?lid=10297

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Re: Finding the right Sear

Post by r_zerr on Fri Nov 27, 2015 8:06 pm

Tim,

there are other reasons that this could be happening.

The simplest is that you do not have enough tension on the portion of the spring that pushes directly on the sear, such that the inertia from the slide coming to a sudden stop causes the trigger to push the sear out of engagement.

The other, which could also be in combination with the the one above, is that you have stoned the hammer to remove the sear engagement too much. 

A third is that you stoned the face of the hammer where the sear comes against the hammer, and it is over a 90 degree angle, which facilitates the sear popping out.

This is where having tools like a surface grinder and an optical comparator are needed for repeatable results.

-Ron

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Re: Finding the right Sear

Post by Tim:H11 on Fri Nov 27, 2015 8:46 pm

r_zerr wrote:Tim,

there are other reasons that this could be happening.

The simplest is that you do not have enough tension on the portion of the spring that pushes directly on the sear, such that the inertia from the slide coming to a sudden stop causes the trigger to push the sear out of engagement.

The other, which could also be in combination with the the one above, is that you have stoned the hammer to remove the sear engagement too much. 

A third is that you stoned the face of the hammer where the sear comes against the hammer, and it is over a 90 degree angle, which facilitates the sear popping out.

This is where having tools like a surface grinder and an optical comparator are needed for repeatable results.

-Ron

I think it's safe to count out problems with the hammer due to the fact that i haven't touched the hammer. Trigger work typically evolves making sure the hammer hooks are proper length and the 90 degrees like you mentioned but upon inspection the hammer looked good so I left it alone. 

With the trigger at 4 lbs now, increasing the sear spring tension would increase trigger pull. So how can I bring it back down with out taking pressure off the sear? The mainspring? If so that would put reliable detonation at risk - if it was lightened too much. Could also let the slide come out of battery early from what I'm told.

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Re: Finding the right Sear

Post by r_zerr on Fri Nov 27, 2015 9:01 pm

Tim,

there are 3 (std design), leaves on your trigger spring.  From left to right, as looking from the rear of the gun, the one on the left is sear pressure, the one in the middle is primarily a combination to push the disconnect back in place and directly against the trigger itself. Increase pressure on the center one, and you can decrease force on the left (sear) one. They work in combination.  I think someone else (John Eullette? )indicated baseline forces on each one, and that is probably a good go-to.

-Ron

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Re: Finding the right Sear

Post by jglenn21 on Fri Nov 27, 2015 9:32 pm

take a hard look at your sear angle with your hammer hooks... magnifying lenses help quite a bit... you'll be able to see your sear engagement.. also use sear and hammer pins that attach to "Your" frame so you get the actual setup. Brownells sells those.

did you use a Power #1 jig to do your sear?  I tried the 2 1/2lb trigger  and had similar issues.. using the standard 1911 sear cuts described by the power jig instructions always worked for me...  I've had them down to 2 1/2lbs  with no issues. the standard cut is 20 clicks up for both the sear angle and relief cut..  I use .018 hooks and a 19lb mainspring.

the 2 1/2 lb instructions for setting the sear and trigger springs works well

playing with the TR sear jig quite a bit these days..

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Re: Finding the right Sear

Post by jglenn21 on Fri Nov 27, 2015 9:37 pm

personally I use quite a few of the STI sears as well as EGW.. also their disconnectors.. Both are of proper length

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Re: Finding the right Sear

Post by Tim:H11 on Fri Nov 27, 2015 9:47 pm

Yes I have and use the Power Custom Series 1 jig. Cut primary at 20 clicks, broke the edge for a relief angle, polished them up with a much finer stone to make a clean smooth pull. Trigger feels great. 4 pounds. Hammer follows with using the slide stop as a slide release though. Stock mainspring. It's a Springfield RO. Mainspring too heavy?

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Re: Finding the right Sear

Post by Tim:H11 on Fri Nov 27, 2015 9:52 pm

jglenn21 wrote:take a hard look at your sear angle with your hammer hooks... magnifying lenses help quite a bit... you'll be able to see your sear engagement.. also use sear and hammer pins that attach to "Your" frame so you get the actual setup. Brownells sells those.

did you use a Power #1 jig to do your sear?  I tried the 2 1/2lb trigger  and had similar issues.. using the standard 1911 sear cuts described by the power jig instructions always worked for me...  I've had them down to 2 1/2lbs  with no issues. the standard cut is 20 clicks up for both the sear angle and relief cut..  I use .018 hooks and a 19lb mainspring.

the 2 1/2 lb instructions for setting the sear and trigger springs works well

playing with the TR sear jig quite a bit these days..


You said you had similar issues? What was the solution? What issues did you have working on the trigger pull?

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Re: Finding the right Sear

Post by jglenn21 on Fri Nov 27, 2015 9:56 pm

I dislike the Springer mainspring so I swap it out for the normal style myself but they will work.

you may need more relief cut if you only broke the edge.. I usually find  my relief to be about 1/4/ to 1/3  width of the primary angle width.. snap caps are pretty light.. try it with a live round( one) from the mag.

have you checked you hammer hook height.  what sear did you use>?

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Re: Finding the right Sear

Post by jglenn21 on Fri Nov 27, 2015 9:58 pm

my solution was to go back to using the standard primary sear angle cut of 20 clicks.. the article you mentioned suggests using something different for the primary angle.  Do try it with  a single live round and see how it works

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Re: Finding the right Sear

Post by Tim:H11 on Fri Nov 27, 2015 10:01 pm

jglenn21 wrote:I dislike the Springer mainspring so I swap it out for the normal style myself but they will work.

you may need more relief cut if you only broke the edge.. I usually find  my relief to be about 1/4/ to 1/3  width of the primary angle width.. snap caps are pretty light.. try it with a live round( one) from the mag.

have you checked you hammer hook height.  what sear did you use>?
Stock sear but polished, stock untouched hammer. I'll measure the hammer hooks again. But if the hammer is following then being too long wouldn't the a problem I should think....  Question

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Re: Finding the right Sear

Post by jglenn21 on Fri Nov 27, 2015 10:08 pm

may be time for a new sear

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Re: Finding the right Sear

Post by Tim:H11 on Sat Nov 28, 2015 9:13 am

Probably the sear, probably too heavy of a mainspring. Don't know. I'm gonna have to get some parts and test and see what they do.

Is it possibly at all my over travel screw could have anything to do with it? Just wondering.

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Re: Finding the right Sear

Post by jglenn21 on Sat Nov 28, 2015 9:54 am

Easy enough to loosen it up and see

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Re: Finding the right Sear

Post by Tim:H11 on Sat Nov 28, 2015 1:05 pm

Not the trigger stop screw. Changed out sear to a rock island sear I found in a parts kit from a friend. It was noticably longer. Stopped the hammer follow issues chambering a round using the slide stop. But in an expirament to toy with the mainspring, cutting coils it no long fires.

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Re: Finding the right Sear

Post by kc.crawford.7 on Sun Nov 29, 2015 7:34 am

Tim, cutting coils on any spring is a bad idea.  Wolff sells spring kits so you can get the proper weight and you'll know what weight you're dealing with if you have problems etc.

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Re: Finding the right Sear

Post by Keyholed on Sun Nov 29, 2015 8:49 am

Wolff's springs also come pretty cheap. $8 or $9 for their reduced power mainspring kit (19#, 20#, 21#, if I'm remembering correctly). Individual springs are something like $4 a pop. Cylinder and Slide pins can be had for $3 per bag of two, so you'll have spares on hand if (when) you manage to lose one. Fairly inexpensive as far as tinkering goes.

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Re: Finding the right Sear

Post by Tim:H11 on Sun Nov 29, 2015 9:05 am

I have springs on order cutting coils was just an experiment to see how  much the mainspring would effect trigger pull.

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Re: Finding the right Sear

Post by Bigtrout on Sun Nov 29, 2015 9:48 am

Maybe it would help to take a look at Jack Wiegand's 2.5 pound pull tutorial on Brownell's website.  I used his leaf spring bending procedure and got my pull to 2 3/4 pounds from 5 1/2 pounds with no hammer follow issues and no change of mainspring.

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Re: Finding the right Sear

Post by Tim:H11 on Sun Nov 29, 2015 10:12 am

I did and issues do to the sear being too short. A problem he discusses in the bottom of that article.

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Re: Finding the right Sear

Post by Jerry Keefer on Sun Nov 29, 2015 11:49 am

I looked over this thread twice, getting old and may have missed it, but I didn't see where anyone mentioned measuring the sear..or mentioned a dimension. How long is your sear?? .404  from the primary tip to pin C/L is a very good length to start. As it shortens, from this dimension, things start to go down hill.. ..It's like headspace.. No body knows...  I have measured thousands of sears, and you might be surprised at the number of sears that are too short right out of the box... Heavy handed stoning,  on a super duper sear fixture,  looking for that "magic" angle shortens the sear further..During the advent of the Warner True Radius Sears, the primary makers of sears were consulted and it resulted in sear lengths being held to closer tolerance than in the past.. So many new sears now, will be .404 or slightly longer.  How long are the hammer hooks??  Are the hooks square??  It's new, so the hooks are square and equalized right??  I doubt it.. Do they make equal contact on the primary face of the sear.?? Equal contact can be perfect, or very elusive... 2.5lb triggers on a 1911 is probably not a good place for one's first trigger job. FEW, are the decent quality frames with improper hole spacing...Spring pressure is the least of the issues with a trigger.. It's the combined geometry of all the parts..The disconnector is a very simple device.. The overall length frequently stated is not the final determing factor. The disconnector has a function to perform. Connnect and disconnector.. How much contact in the up position, and how much clearance at the disconnect function does the disconnector have.?? Each can be adjusted. The 1911trigger is really a crude system with a "push" trigger, rather than the conventional "pull" that gunsmiths have fought for decades to function and perform like a precision target system.. It's an up hill battle. Starting with a near perfect sear of .404 makes the rest much easier..I believe I posted a letter some where on the forum, from a Marine Bullseye Team Armorer, which states the challenges and frustrations of the 1911 trigger..

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Re: Finding the right Sear

Post by Tim:H11 on Sun Nov 29, 2015 10:42 pm

Did some review reading, some sear shopping and ordered an "STI Premium Sear S-7 1911". Supposedly for the money it's a quality sear and should serve well. 

From Wolff Gun Springs I ordered a replacement factory 30# mainspring as well as the reduced power mainspring pak including a 24, 26, and 28 pound mainspring. I also ordered a new sear leaf spring. 

Hopefully, with these quality parts on the way I ought be able to have a combination that will produce the lighter yet bullseye legal trigger pull, and not have any hammer follow issues.

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Re: Finding the right Sear

Post by Jon Eulette on Sun Nov 29, 2015 10:56 pm

Those mainsprings are really heavy. Typically I use 21# for my .45 caliber  pistol builds. 22 Conversions I use 19#. Not that those won't work, but not typical for BE use.
Jon

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Re: Finding the right Sear

Post by Tim:H11 on Sun Nov 29, 2015 11:24 pm

On the Wolff Spring website they only offered those poundage mainsprings for the Springfield ILS Mainspring. Lighter mainsprings are used for lighter triggers right?

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Re: Finding the right Sear

Post by Rob Kovach on Mon Nov 30, 2015 2:06 am

Tim,
The mainspring doesn't have a direct relationship to trigger pull weight per se.

I run a 19# mainspring in all my guns, but my triggers are set for 4#.

It's all about the balance of the mainspring, leaf spring, and firing pin spring.

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