Hammer Follows --- but passes safety checks

[Seth]

My STI Edge was recently returned to me from STI where she got a tune up and a trigger job. With it set to 3#, the pull was fantastic and crisp, but I forgot to get them to swap in a short trigger. After take a few careful measurements, I ordered the trigger and installed it yesterday. Prior to installation, I polished the bows and fitted the trigger to the frame as closely as I could without any bind.

Range tested today, I ran about 300 rounds through it without issue. Handed it to a buddy of mine who's an A class shooter and has a SERIOUSLY fast split time (RO accused him of going full auto) the hammer followed. I didn't see it do it but once and that was to the half cock notch, but he says it was following all the way when he was blazing every so often.

I adjusted the overtravel and couldn't get it to do it again, nor could he. The disconnect was working properly prior to my buddy wailing on it and passed all safety checks.

Should I be actively concerned and have it checked out or was the overtravel causing the issue?

TIA.

Seth

Edited April 26, 2008 by Sethmark

[HSMITH]

The overtravel screw can do it. What can happen is the sear nose will get bounced by the hammer as it cocks and if it doesn't get back in time the hammer will follow the slide down. Make sure you can hold the trigger back and hand cock the hammer very slowly and carefully without feeling ANY sort of a bump or hitch in it. If that feels OK shoot it a while and see what shakes out.

[Seth]

Gun in strong hand with good grip, trigger pulled all the way back. Thumb the hammer back with weak hand, hear a slight click at 1/2 way. Nothing else on the way up, clicks again at almost the half cock notch on the way back.

Thoughts? Thanks Howard!

[Trader]

I have a 9mm SS that was a .38 super and has mega rounds on the hammer and sear with never a failure.

I put my Marvel .22 kit on it and it goes to half cock a couple times. Next it doubles, then ok for a while, then it

triples. I put the 9mm top back on and I can't make it fail.I tried the Marvel again , same results.

Finally I just fit a new hammer and sear and all is ok with the Marvel after 500 rounds. It was probably time for

new parts but I could find nothing wrong with the engagement of the sear and hammer hooks.

[HSMITH]

Your overtravel screw is still too tight, back it off until there is NOTHING at all, then back it out another 1/8th turn. Pull the trigger out, put a drop of super glue on the protruding threads and trigger shoe. Let it dry, assemble and you are good to go.

[Seth]

As it turns out, it is all the way out. The trigger itself is bottoming out on the frame now.

I played with it with the mainspring housing unpinned and slightly past the strut and its smooth. With the grip safety and thumb safety out and the msh in, the hammer strut SEEMS to be moving on the pin in the MSH and causing the click.

Not 100% sure that its the MSH, but it seems to be. I'll swap one from a buddies STI and see for sure. That isn't the following issue, though. I'll take your advice on the overtravel and see how it does. Any reason I can't just take it out?

[HSMITH]

Hi Seth, I often take them out. It won't hurt anything and I shoot better with some overtravel before the trigger stops.

Two more check points, make SURE the strut isn't touching the sear spring in any way. Second, pull the trigger and make sure the back of the bow isn't bowed out. It needs to be dead flat across the back, and can even be bent in a touch as long as it doesn't contact the magazine. Measure the length of the bow compared to the trigger you pulled out, I have seen STI triggers with bows that were long and bent both right out of the package.

[Seth]

The strut and sear spring are nicely parallel and I don't see any indication of the strut touching the disconnector leaf.

The trigger bows were about .015 longer and about .008 narrower. Per your advice, I go them as close to each other as possible.

As I've messed with this, I've started to wonder about the damage I'm doing to the sear and hammer. The Dawson mags I bought don't have a provision for locking the slide back empty. Is that the equivalent to dropping the slide on an empty chamber EVERY time I run the gun dry? Have I created a monster? Should I NOT be running the gun dry with those mags? Accordingly, have I killed a perfectly good trigger job doing this?

Seth

[HSMITH]

Seth, don't worry about the trigger job and running the gun dry. As long as the trigger is pressed you cannot do any harm to the hammer and sear, and it will be if you are shooting the gun dry. I don't believe in triggers so fragile as to be damaged by dropping the slide on an empty chamber and do it several times to each gun I work on, it MUST pass that test or it doesn't leave the shop. If the hammer drops when the slide is dropped on an empty chamber the geometry of the hammer and sear is wrong, I don't care what the pull weight is. Drop the slide on an empty chamber a couple times, does the hammer drop? Remember, if it follows it was screwed up to begin with and you didn't cause it. I am not advocating doing it as a course of habit, but every thousand rounds as a matter of checking the health and welfare of your blaster won't hurt a thing.

.015" long is quite a bit really, if your sear legs are a little thick and the hammer hooks a little short it all adds up. .008" narrow isn't a lot, but it can be if you have a fat mag in use. Drop the bow on ALL of your magazines, if it clears them all things are fine, if it drags on ANY of the magazines let me know.

Cause and effect can sometimes get deep, don't worry though, it will work out.

If you have any questions PM me your phone number and times you can take a call. I'd be happy to talk to you about it.

[BSeevers]

Hammers that follow eventually double or worse., Fix it

[DaG]

Good article here.....http://www.cylinder-slide.com/1911safetyck.shtml

DaG

[Seth]

Bill,

I'm TRYING to fix it. Got any suggestions??

Edited April 27, 2008 by Sethmark

[Seth]

So I did a thorough detailed cleaning today and now feel a whisker of resistance about where the hammer would catch at full cock. Smooth travel, no more click, but the slightest bump.

Howard, you've got a PM!

Seth

[HSMITH]

Seth, nothing came through. Shoot it off again.

The little bit of a funny feeling at full cock isn't a big deal, that is very close to where it will cam over and the mainspring starts to release again. Shoot that bad boy and see what happens, carefully of course LOL.

[Josh Biondi]

My STI Edge was recently returned to me from STI where she got a tune up and a trigger job. With it set to 3#, the pull was fantastic and crisp, but I forgot to get them to swap in a short trigger. After take a few careful measurements, I ordered the trigger and installed it yesterday. Prior to installation, I polished the bows and fitted the trigger to the frame as closely as I could without any bind.

Range tested today, I ran about 300 rounds through it without issue. Handed it to a buddy of mine who's an A class shooter and has a SERIOUSLY fast split time (RO accused him of going full auto) the hammer followed. I didn't see it do it but once and that was to the half cock notch, but he says it was following all the way when he was blazing every so often.

I adjusted the overtravel and couldn't get it to do it again, nor could he. The disconnect was working properly prior to my buddy wailing on it and passed all safety checks.

Should I be actively concerned and have it checked out or was the overtravel causing the issue?

TIA.

Seth

Has anyone think to push ahead a little the middle leaf of the sear spring to give it just a little power more ?

[bountyhunter]

The overtravel screw can do it. What can happen is the sear nose will get bounced by the hammer as it cocks and if it doesn't get back in time the hammer will follow the slide down. Make sure you can hold the trigger back and hand cock the hammer very slowly and carefully without feeling ANY sort of a bump or hitch in it. If that feels OK shoot it a while and see what shakes out.

+1

The right way to check an overtravel screw adjustment is to tap the pin out of the main spring housing to release spring pressure, then pull the trigger all the way back and hold it. Use your thumb to slowly raise and lower the hammer all the way and see if you feel any drag as the hammer hooks move past the sear nose. The half cock notch sticks out farther than the full cock notch, if it's going to rub it will probably rub on the 1/2 cock notch. You need to adjust the overtravel screw until the hammer moves past the sear nose with NO CONTACT.

[bountyhunter]

duplicate

Edited April 28, 2008 by bountyhunter

[Seth]

I'm certain that the overtravel is now adjusted properly. The bump/ 3rd click I was hearing was definitely in the mainspring housing, and I'm assuming its coil binding on plastic.

The only thing left that concerns me is that I can see the sear/disconnect pin move SLIGHTLY on the port side of the gun. The pin doesn't move on the other side. Is a tiny bit of pin movement when thumb cocking the hammer between the half cock and full cock notch normal?

Edited April 28, 2008 by Sethmark

[HSMITH]

radial or axial movement?

[Seth]

Axial. Just enough that it displaces the little bit of oil around the pin hole. Clearly the hole is oversized a whisker... but what's the tolerance?

[HSMITH]

Throw an EGW pin kit at it when you order your gear, they usually fit perfectly to a little oversized. If they are oversized for your frame you can put them in the polish lathe with a little sandpaper if you don't have a way to turn them down or ream the pin holes.

[Seth]

Well.... a swing and a miss. 150 rounds thru her tonite and she fell to half cock at round 135. So... it ain't the overtravel.

On the flip side, I sorted out the pin issue. Turns out the port side it .001 bigger than the other side. I had a spare parts pin laying around that was a little bigger and she seems to have solved that issue.

Meanwhile...

[HSMITH]

Looks like you have a geometry problem between the hammer and sear. Send it back, at this point you know it has nothing to do with the trigger that was put in.

[bountyhunter]

Looks like you have a geometry problem between the hammer and sear. Send it back, at this point you know it has nothing to do with the trigger that was put in.

That's what I was thinking. The sear and hammer faces are so critical to get a perfect trigger pull it's easy to get them off a touch and have random hammer follow.

As Josh mentioned sear spring pressure above, I was wondering if that had been checked? I know you said 3# trigger pull, but the sear spring has to be measured separately. One leaf of the sear spring pushes on the trigger, one on the sear. They should be about equal. measure as follows:

Get a good trigger pull gauge.

Hold the hammer fully back with your thumb.

measure just the first part of the trigger's movement before it engages the sear and see how much spring force there is. That is the "trigger return" leaf.

measure the trigger pull to where the trigger would normally break (hammer must be pulled back for this) and that measures both leafs of the sear spring. The "sear return" leaf force is the second reading minus the first. usually, on a good trigger setup, you only need maybe 10 - 16 ounces (each) to work, higher is OK. The two readings should be approximately equal.

You can probably stop the hammer follow by increasing the tension on the "sear return" leaf, but that won't fix the underlying geometry problem. With a 3# trigger, you should easily have enough pressure from the leaf to work without hammer follow. Some 1911's have triggers at 1.5# that don't follow, which means the sear spring force is really light.

Edited April 29, 2008 by bountyhunter

[pskys2]

Make sure your Grip Screws didn't loosen up. If they do they can contribute to a hammer following.

When a hammer falls to half cock check the sear for any ridges that might develop on the sear. Sometimes the HC Notch will burr the sear when it follows. If it does you may need to clean it up.