hammer drops to half-cock

[Kruzr]

Yep, you're right, I was thinkin' about why it was dropping from a captive half cock notch (if it is a captive one.)

Little somethin' in the patents for you, too. Lemme go see where it is.

I've read it, it talks about "momentum" of the slide.

(Lines 20 - 50 or so?)

 

[1911Tuner]

Nah. Section 5, paragraph 25.

 

[navyretired 1]

If a simple shelf would have done the trick the series 80 hammer wouldn't have that ugle wedge sticking out. When the trigger is being pulled the sear is out of position to stop the sear in either case. If that were not so every time you pulled trigger the sear would bang against safety notch. When thumb cocking you drag the finely tuned sear surface across safety notch which can and does destroy a trigger job or a normal trigger sear surface, which is why its a good but ugle idea to hold trigger back if thumb cocking, don't forget to let go of trigger before hammer if you don't want a bad day, or preferly don't thumb cock weapon, it's never really safe and we all know we cock and dry fire weapon. To fix this problem Colts decided to put that wedge in because it will still stop a falling non-trigger pulled hammer but will also not batter the area of fitted sear surface which is normally mated to hammer.
I make no claim of knowing what was on JMB mind but as an engineer I can look at a mechanism and figure out how it works. We're arguing apples and oranges and not getting answers to questions ask of OP so a proper troubleshooting can accur. His initial statement that a trigger pull will drop hammer from half cock is kind of hard to beleave as normal trigger geometry doesn't work that way. I've never had a complaint on my government model work. Long distance troubleshooting is hard at all times and without the answers to questions ask it's almost impossible. BTW I think almost anybody would answer the series 70 style hammer if ask is it the series 70 or 80 which was the question I think. Most GM pistol smiths know what the series 70 changes were and I for 1 don't care for collet bushing. The only comeback I've ever got besides (not 3 1/2 Lb) is for a broken finger in a Steel Challange match in 1985. It took a whole day to get that gun apart without destroying it.
Navy

 

[1911Tuner]

We did asnwer the OP's questions as far as we could go with it. Now we wait and see what was causing his problem.

I didn't start this. All I did was suggest...merely suggest...that the half-cock notch might be an intended safety, and stated the reasons why I thought so. Turns out that I was right.

And why would thumb-cocking the gun destroy the sear? The hammer drags across the
off side...where the breakaway angle is often cut in the process of doing a trigger job...and never touches the primary surface. So, how can dragging against the hammer on the same place where many smiths deliberately stone a relief destroy the sear...match tuned or otherwise?

And why would anybody pull a trigger before thumb cocking a hammer on any gun? I fail to see how that would be a "good idea" under any circumstances.

Finally...I didn't whizz on your shoes. I stated a theory...rc challenged it...I responded with my reasoning and analysis...you backed up his response...I looked in the patents and found that the half-cock was indeed a safety, by design and intent. Are we to assume that Browning was an idiot who didn't understand his own gun?

Anyway...We wait to see what bug was nesting in the OP's fire control group. We've pretty well got it narrowed down to disconnect or sear spring.

 

[sophijo]

new thing

Just noticed today during minor "fiddling" before work that with hammer at half-cock notch I can push on the hammer and it will depress a little with an audible "click", after which it will not fall when I pull the trigger. Pull the hammer back to full-cock, release it manually to half-cock and it will fall when I pull the trigger. I will inspect more thoroughly this weekend. BTW after reading your thoughful posts I'm wishing the good Lord had granted me a few more IQ points!!

 

[1911Tuner]

That sounds like the captive notch itself isn't to spec. The sear should enter easily and be trapped. Since I don't know what Fusion's sears or hammers look like, I guess the sear could also be a player. Pretty much a non issue unless you intend to use the half cock as an active safety. As long as it grabs the sear during a free fall, it's doing what it's supposed to.

Dunno why these manufacturers can't seem to get the specs and dimensions right. It ain't like they can't find an old USGI pistol or a pre-Series 70 Colt to reverse engineer.

 

[sophijo]

check for understanding!

The half -cock issue and the hammer follow are unrelated.
The hammer either has a half-cock notch or a shelf on which the sear nose catches when hammer follows. If its a notch, that may be out of spec. Could be the sear nose.
>The hammer follow is one of the following or a combination;
>Middle leaf spring tension too light
>Sear/hammer fitment damaged
>Disconnector issues.
I need some help with the disconnector involvement. I've watched the STI animations, read here, and Kuhnhausen and still having a tough time getting it.
Could the trigger over-travel be too deep?

 

[rcmodel]

Put the gun together without the grip safety.

Without it in the way, you can watch the disconnector work.

rc

 

[Old Fuff]

Dunno why these manufacturers can't seem to get the specs and dimensions right. It ain't like they can't find an old USGI pistol or a pre-Series 70 Colt to reverse engineer.

They don't even have to buy a gun, because the USGI blueprints and material specifications are available - but I can tell you this, any relationship between those prints, and the guns being made today is to say the least, unexpected and unlikely.

Maybe that's the reason so much of the new stuff simply doesn't work. :banghead:

 

[1911Tuner]

Could the trigger over-travel be too deep?

Unless the trigger's stop surface in the grip safety is way out of spec, it can't go so deep that it would interfere with the disconnect reset. This isn't to say that the stop surface isn't out of spec. I've seen one that was, but can't remember whose grip safety it was.

Just for sheets and geegles, look to see if the center leg of the sear spring has a slight kink in it, about 1/8th inch from the top. Also have a peek at the angled portion at the rear on the disconnect spade...where the spring rides. Is it straight, or concave...like it's been scraped out?

 

[sophijo]

progress

I completed the clean/ inspection today using this tutorial:
http://how-i-did-it.org/detail-1911/frame_detail.html
It's well-done.
I didn't see anything that was obviously wrong other than some crud, but then again don't have an expert eye!
The half-cock notch did have a small radius at the inside corner, as if the cut hadn't been quite completed. I, very gently, stoned that square, and added a smidgen of tension to the center leaf on the sear spring.
No irregularities on the sear that I could see.
I didn't see any of the wear on the disconnecter that Tuner hadn't mentioned to look for.
I'll shoot Tuesday and see what happens!
Thanks again for you guidance.
Dave

 

[sophijo]

update

I stripped it again after some more reading.
Added some tension to the left leaf too.
Noted the the disconnector "tongue", which contacts the trigger, was sharp. You could probably cut your finger on it. The sharp edge was not square with the sides either. Don't know if that matters functionally but it does look genky.
The sear nose appears, under magnification, to be almost radiused instead of having an acute edge as seen here on another thread. It almost looks as if there was an edge which had been worn, but I only have 1k rounds through it and an equal number of dry-fires. Not having those critcal fitment skills I left it, but will study it. Been dreaming about EGW action pack!
Backed out the trigger over-travel screw just to rule out that.

Shot 50 Fiocchi 230 FMJ, and 50 200 LRN, through it today and got three "follows" to the halfcock notch. I noticed on the first one that I had "limp" wristed" and was able to recreate that drop 2 more times with a loose grip. Otherwise it was 100%.

BTW I used my Dan Wesson CBOB as a comparison and it ran comparable rounds without issue. I haven't detailed that gun but will ASAP as that would be a great comparison.

Thanks
Dave

 

[1911Tuner]

The spring tip absolutely can have a bearing on the issue. It should be lightly beveled and polished smooth...and square...and it needs to contact the spade at the right place, neither too high nor too low. Too high and pulling the trigger forces the disconnect out of position,and the hammer sotps at half-cock/failure to fire. Too low, and it can interfere with disconnect function...which interferes with proper sear reset...and cause hammer follow. In extreme cases, it cac cause burst/full auto fire. That's why I asked you earlier if the spring leaf had a slight kink near the top.

Sounds like you need a new sear spring that's been correctly prepped.

 

[rcmodel]

It almost looks as if there was an edge which had been worn, but I only have 1k rounds through it

Many of which allowed the hammer to drop to half-cock apparently.

Your sear is damaged now, and you are fighting a losing battle until you get a new sear, or a sear jig and repair the one you have.

rc

 

[sophijo]

update

New sear, disconnector, sear spring, hammer/strut arrived today. Install pretty straight-forward except for binding pins in sear and hammer both. Polished them with 1000 grit paper until they fit smoothly. "Dry" tests look like the half-cock issue has been resolved. Take-up increased to about 035+. I'll shoot next Tuesday and as they say, "the proof is in the putting" or is it pudding(?). Thanks for you help! I'm feeling pretty spiffy!!