Very crisp and HEAVY 1911 trigger

[larryw]

In a bit of a quandry here. I've been working on a Longslide 1911 to set up for bullseye. Have the gun running very nicely, super accurate and the trigger is very crisp. Very crisp. Proverbial glass rod. And at about 7 pounds, the glass rod must be the size of a Coke bottle.

How the heck did I do that? :banghead:

I think I have everything done according to the 1911 thread above, hammer hooks are square, .020" (light loads, strictly a fungun). Contact on sear face looks square and even...

So, what did I do wrong? Suggestions on where to look would be greatly appreciated.

thanks,
LW

 

[1911Tuner]

Heavy Trigger

Well, I ain't no kinda whiz-bang trigger man, but I can give ya a couple things to check.

Sear primary angle doesn't agree with the hammer hook angle. Maybe the
hooks are sitting on the tip of the hook, and as the sear rotates, it's trying to push (cock) the hammer farther back against the mainspring.
You can test this with a dial indicator. Cock the hammer and lock it in a vise. Zero the indicator on the hammer and slowly squeeze the trigger
and watch the needle.

Does the sear have a breakaway/escape angle on the backside? How
wide is the primary angle? have you tried bending the middle leg of the sear spring backward to lighten the tension against the trigger and disconnect? Are you sure that the hammer hooks are square? Are both
hooks bearing evenly on the sear? One hook bearing all the load makes for a heavier trigger.


You can bend the left leg out just a TINY bit...but be careful with this one. The sear resets off that leg, and overdoing it can cause
hammer follow and/or burst fire. If you have a test gauge, you'll want a minimum of 12 ounces on the left leg and 8 on the center leg. Some say
8 ounces on the left one, but I ain't buyin' it...not with hammer hooks that short and dead square.

'Bout all I can tell ya...Dave Sample or Jim Keenan can probably go a little deeper into the issue.

Luck!

Tuner

 

[m1911joe]

What sear spring did you use?

Try taking the the hammer and sear out and see what kind of pull you
have with just the trigger.

If it is the 3 finger style. Look at the middle finger try and put a little more
bow in it. That should take some of the weight off of it.

If you used the 4 finger style. The two fingers in the middle are (left one)
pushes on the disconnect and the right one pushes on the back of the
trigger. Putting more bow in these will help some.

I am no expert. But I did stay at a Holiday Inn last night.

PS hope this helps till Tuner gets here.

 

[larryw]

I marked the sear and hammer hooks with a sharpie and dry fired a couple times, looks like the contact is even and square.

I'll try the dial indicator suggestion (Woo-hoo! I finally have a use for the one I've had in my tool kit for almost the past two decades ). Need to find the magnetic mount though...

Throwing another wrench into the works. I had a Wolff sear spring (3 finger) and on a whim, I put the factory spring back in last night. Now the trigger is almost usable, maybe down to 5#. I'm going to work on it with the factory spring until I get a good pull, then fight with the aftermarket spring.

Thanks for the suggestions!

LW

 

[1911Tuner]

Sear Spring

Howdy larry,

Wolf sear springs come in in an untweaked condtition, with the assumption that the installer will tune'em. A factory Colt sear spring, straight out of the package will probably knock another 8 ounces or so off your trigger pull.
Available from Brownells for about 5 bucks. They're in the factory parts
section near the back of the catalog.

Luck!

Tuner

 

[larryw]

Yeah, I thought I had tweaked the spring properly before I used it; apparently not, eh?

But the spring swap did tell me I have more work to do before I tackle that task again. Thanks for the help.

 

[1911Tuner]

Sear Spring Tune

Larry...a thought.

Did you stone an angle at the top of the center leaf of that Wolff sear
spring? Right there where it bears against the back of the disconnector?
make it match the angle on the disconnect...about 48 degrees...as closely
as you can with the mainspring housing putting tension on it. Polish it smooth from the top of the leg toward the middle.

Standin' by...

Tuner

 

[Dave Sample]

Did you clean up the tracks in the lower end where the hammer strut rides? Wolf sear springs are good to go out of the bag, if you tweak them like Tuner advised. Trigger work entails much more than the sear nose and the hammer hooks. The left leg of the spring has to be cleaned up and the right leg should be beveled where the grip safety rides on it. Good Luck.

 

[bountyhunter]

You can measure the sear spring force on both the disconnector (center) and sear (left) legs without taking the gun apart.... if you have a trigger pull gauge. Hold the hammer all the way back and gently pull the trigger.

1) The first "take up" movement is the trigger moving against the disconnector and it's leaf (the center one).

2) As you pull farther, it starts rotating the sear which is moving against the left leaf.

If you carefully measure the trigger pull on take up BEFORE it gets to where the sear starts moving, that is the center leaf spring load force.\\ Then measure the weight to rotate the sear (remember the hammer has to be pulled out of the way so the sear can move freely). The second number is the weight of both the center and left leaf. Subtract reading #1 from #2 and you will get the sear leaf force alone. Then, measure the trigger pull as normally done and that gives you how much additional force is needed to move the sear face across the hammer hooks. If you have a steep angle (as Tuner explained) and you are deflecting the hammer to the rear as the sear moves, you will see a big value for the third component of the measurement.

FWIW: I recall on my STI that it takes an additional 1/2 pound more or less for the sear/hammer part on a total trigger pull of about 2.4# (it's set up for comp shooting).

 

[larryw]

Thanks for all the suggestion guys. I did spend some time with this over the weekend and am getting there. It looks to be a combination of several things: sear spring was too tight (fixed and polished), trigger stirrup had a burr on one leg that I had missed (D'oh! fixed) and the sear itself seems to be dragging. I ordered a nifty sear/hammer jig from Brownells and will square up and polish this once I can do it right. I'll also polish the area where the strut rides like Dave suggested.

And BH, thanks for you posting: that great stuff, very helpful when trying to find the root of the problems.

Thanks again!

 

[larryw]

Jig came with today's mail (love Brownells FAST service). Spent some time working on the hammer and sear: hammer was fine, but the sear angle was way-way off; never would have been able to figure that out w/o the jig. Now that's fixed.

Reassembled and pulled the trigger. Wow, what a difference! Light and crisp trigger. Maybe 3#...perfect.

I hope to test fire tomorrow, but have range duty at the club (I'm really hoping for about an hour or so with no customers...). I'll start with three in the mag for a while and then go up to full mags once I'm sure I haven't built a Class 3 1911.

One question for the gurus. The sear jig lets me adjust the angle of the sear engagement, but the hows and whats weren't explained; how does that affect the trigger pull? Will cutting a sharper angle decrease trigger pull?

Thanks again for all the help!

Next thread we talk about why I'm getting random flyers...

 

[bountyhunter]

The sear should have two anges: the primary cut and the secondary (relief) cut. The primary face cut is what must capture the hammer as it comes forward with the slide. If you get that angle too flat, you will get hammer follow because the hammer can bump the sear and slide by. Of course, if you go too far the other way on the primary angle, then you get evry good hammer capture but a heavy trigger because as you pull the trigger the sear is deflecting the hammer to the rear.

The secondary (relief) cut is basically there to remove metal from the sear's primary contact surface so that when you pull the trigger, the sear doesn't have to go as far before the hammer falls (removes creep). Again, if you get too aggressive and reduce the primary face surface area too much, you will get hammer follow.

I don't know the optimum angles, I bet tuner can direct you there. As I recall the fixtures are calibrated. I know jack Weigand wrote a white paper on trigger jobs and it is posted in the technical info section at Brownells. I recall he specified the cut angles but I don't remember what they are.

http://www.brownells.com/aspx/NS/GunTech/newsletterarchive.aspx

Third line down: "2 1/2 pound trigger pull"