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  #1  
Old 07-21-2011, 11:18 PM
magcatch magcatch is offline
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Pre-travel...take-up tabs...




I've got two 1911's. I learned by disassembling my Kimber (Schwartz safety, external extractor) and putting it back together. I started doing small mods and then I bought a Springer G.I. and got heavy into rebuilding it myself.

What I don't really understand properly are those take-up tabs. When disassembling my Kimber (and the G.I.) the tabs on the trigger bow looked like they had never been touched. In turn I never really fooled around with them nor learned about their proper function. What I did use was the over-travel screw to adjust the travel. My 1911's have always passed their safety tests.

I guess what I'm asking is how the tabs relate to pre-travel in conjunction with the over-travel screw? And if there's an over-travel screw, then why the need for the tabs in general? Since I do my own work I should probably learn about this subject so I fully understand the function of the pistol.

Thanks.
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  #2  
Old 07-21-2011, 11:26 PM
log man log man is offline
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The trigger has two stop points, at rest, which is all the way forward, and fully to the rear. The pre-travel tabs can lessen how far forward the trigger can go, there by lessening the pre-travel. And the screw in the trigger limits over-travel, how far back the trigger will go. There must be enough pre-travel for the sear to fully seat in the half cock notch. Pull the hammer to half cock, and if there is more than just a slight slack, it can be reduced by bending the tabs forward, but to much and no slack, function problems will develop. Over-travel can be limited to the point that the sear nose doesn't rub against the half cock notch as the hammer passes the sear when the trigger is held to the rear.

LOG
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  #3  
Old 07-21-2011, 11:32 PM
magcatch magcatch is offline
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I want to make sure I'm understanding you Log.

With the slide in battery, gun unloaded (of course) and no mag in the gun, bring the hammer back to half-cock, correct?

I did this and felt no slack at all, the trigger was solid, no movement at all. You mentioned this isn't the best scenario, that there should be a little slack. You also said that it could (or would?) cause problems in the future. What type of problems could arise? So far I've had no problems and I've shot a lot of rounds out of it, but that doesn't mean a problem can't creep in at some point.

Over-travel is fine, passed all safety tests.

Thanks.
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  #4  
Old 07-21-2011, 11:46 PM
log man log man is offline
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Quote:
Originally Posted by magcatch View Post
I want to make sure I'm understanding you Log.

With the slide in battery, gun unloaded (of course) and no mag in the gun, bring the hammer back to half-cock, correct?

I did this and felt no slack at all, the trigger was solid, no movement at all. You mentioned this isn't the best scenario, that there should be a little slack. You also said that it could (or would?) cause problems in the future. What type of problems could arise? So far I've had no problems and I've shot a lot of rounds out of it, but that doesn't mean a problem can't creep in at some point.



Thanks.
Well at the least it says you should not reduce the pre-travel.

Too little pre-travel can be a contributor to hammer follow and re-set problems. It is simply a way to judge the pre-travel. What is happening and the reason the trigger is tight is the sear nose is trying under sear spring pressure to fully enter the half cock notch, which in most hammers is deeper than the full cock, and the trigger won't go forward far enough to allow that full engagement. Not a big surprise in production guns for this condition to exist.

LOG
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  #5  
Old 07-21-2011, 11:52 PM
magcatch magcatch is offline
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I'm not sure if I explained it correctly.

When I pull the hammer back to half-cock it engages the sear and stays put. While it is resting in half-cock the trigger doesn't have any forward or backward play at all, it doesn't move.

When the hammer is cocked there is pre-travel, then as I start rearward pressure on the trigger the bow starts moving the sear and the hammer falls.

When the hammer isn't cocked there is also rearward pre-travel.
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  #6  
Old 07-22-2011, 12:00 AM
log man log man is offline
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Quote:
Originally Posted by magcatch View Post
I'm not sure if I explained it correctly.

When I pull the hammer back to half-cock it engages the sear and stays put. While it is resting in half-cock the trigger doesn't have any forward or backward play at all, it doesn't move.

When the hammer is cocked there is pre-travel, then as I start rearward pressure on the trigger the bow starts moving the sear and the hammer falls.

When the hammer isn't cocked there is also rearward pre-travel.
Exactly as I understood it.

If it was my pistol I would increase the pre-travel so there was just a smidgen of trigger slack when in half cock as a minimum. My personal setting for pre-travel goes just a little further, but recognive it isn't absolutely necessary. That is to have enough pre-travel to re-set when you from battery hold the trigger back and force the slide back far enough to cause the hammer to engage the half cock. Release the slide to battery and release the trigger, it should reset.

LOG
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  #7  
Old 07-22-2011, 12:24 AM
magcatch magcatch is offline
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Okay, I did the test and from half cock the trigger will reset, allowing me to pull the trigger again, which releases the sear from half-cock, allowing the hammer to drop completely on the FPS/firing pin. Is this not good or am I good to go?

Thanks Log.
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  #8  
Old 07-22-2011, 12:28 AM
log man log man is offline
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Originally Posted by magcatch View Post
Okay, I did the test and from half cock the trigger will reset, allowing me to pull the trigger again, which releases the sear from half-cock, allowing the hammer to drop completely on the FPS/firing pin. Is this not good or am I good to go?

Thanks Log.
Good to go. You didn't say make and model, but it must not have a captive half cock, common in SA and most Series 80 style 1911's.

LOG
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  #9  
Old 07-22-2011, 12:33 AM
magcatch magcatch is offline
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It was the Kimber. The Springer G.I.'s hammer, pretty much everything stock, was stripped out. I'll have to check my Springer next (it's in pieces right now). Thanks for the great advice and explaining the difference between the over-travel screw and the tabs on the trigger bow. I guess my next question would be how to properly bend out the tabs without breaking them? Also what do the tabs grab onto, the trigger bow channel?

Thanks.
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  #10  
Old 07-22-2011, 07:17 AM
wardog68 wardog68 is offline
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Logman, thanks for you info, I have a question:

I've adjusted the pretravel tabs on my STI trigger (the plastic one) on my SPARTAN 9mm. Trigger has some pretravel, when hammer is at full cock.

Using the technique you suggested, with the hammer at half cock, the trigger is totally blocked, don't move at all, no pretravel at all, but when I rack the slide to half cock, the trigger reset.

I've smoothed all the contac points (sear legs, trigger bow, disconnector faces, sear and disconnector spring legs, hammer leg, and mainspring housing)as you suggested in a previous thread, but I've observed that when I've adjusted the pretravel tabs (and the overtravel screw with the technique you suggested) trigger pull has increased from 4lbs to 5.5 and reset is somewhat mushy, do you think I must increase pretravel bending back the tabs?

Thanks for any info.

PS: the spartan is a series 70 (I bet you know, but just to be sure.)

Last edited by wardog68; 07-22-2011 at 07:17 AM. Reason: explaining better
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  #11  
Old 07-22-2011, 11:04 AM
log man log man is offline
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I question the trigger, disconnector resetting when in half cock.

When doing this test you must start with the trigger being held back against the over-travel stop, and keep it there. Then force the slide back just far enough for the hammer to catch the half cock notch. Release the slide to battery and then release the trigger. It should reset. You will also be able to detect just a little slack in the trigger.

Quote:
I've smoothed all the contac points (sear legs, trigger bow, disconnector faces, sear and disconnector spring legs, hammer leg, and mainspring housing)as you suggested in a previous thread, but I've observed that when I've adjusted the pretravel tabs (and the overtravel screw with the technique you suggested) trigger pull has increased from 4lbs to 5.5 and reset is somewhat mushy, do you think I must increase pretravel bending back the tabs?
Very few triggers should have the tabs adjusted at all. I notice among small groups that pre-travel is meet with a negative opinion, it shouldn't.
Pull weight increasing 1.5# indicates a sear spring problem to me. Pre-travel and over-travel do not control pull weight. Yes, it sounds as if your pre-travel is too little.

While playing at home dry firing and such all may feel well with too little pre-travel, but at the range you may experience what some call a dead trigger. You're blasting away having a good time and you pull the trigger and nothing happens, rack the slide and an unfired cartridge pops out, and then it shoots okay again. That can be a too little pre-travel experience.

LOG
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  #12  
Old 07-22-2011, 01:24 PM
GunBugBit GunBugBit is offline
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Good stuff log man. Very clear explanations.
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  #13  
Old 07-22-2011, 02:23 PM
wardog68 wardog68 is offline
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Thank you so much, log!

Me knuckledragger adjusted the tabs too far forward. I started again with the tabs at full rest (even with the trigger bow) then bend only one side little by little until the free play (not the pretravel, only the free play of the trigger bow, the darned thing wiggled in the trigger tunnels like a drunk Italian on monday early morning..). I removed the the play untile the sloppines was almost gone, and then stop, trigger now have a pretravel of some .90 inches, but all the safety test including the half cock disconnector reset test, passed.

I also played with leaf spring tension, gettin an even 32 oz from both the disco and sear spring. My trigger returned to 4lbs.

Well, is safe to say that the interiors of the sti spartan are a little ROUGH..but now at least everything works..
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  #14  
Old 07-22-2011, 05:03 PM
Snoopy47 Snoopy47 is online now
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Educate me, you have pretravel adjustment on your 1911 trigger?

How does that work, how can I upgrade this on my 1911s?

I know overtravel just fine, and I have a pretravel adjustment on my Ruger 22, and I thought it would be neat to have that on my 1911's but I dont see how it can be done.

Thanks,

*********
Well, I have some idea now, wouldn't this be also done more correctly with a longer bow?

BTW I can't find triggers with these adjustments on Brownells. Am I blind?

Last edited by Snoopy47; 07-22-2011 at 05:21 PM.
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  #15  
Old 07-22-2011, 05:47 PM
BBBBill BBBBill is online now
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Quote:
Originally Posted by Snoopy47 View Post
Educate me, you have pretravel adjustment on your 1911 trigger?

How does that work, how can I upgrade this on my 1911s?...
Well, I have some idea now, wouldn't this be also done more correctly with a longer bow?
BTW I can't find triggers with these adjustments on Brownells. Am I blind?
Various triggers are sold with pre-travel adjustment tabs on the front of the bow. Or you can make your own with a form die and punch or a dremel and cutoff wheel. The tab is bent forward to impenge on the front inner curve of the trigger mortise limiting forward movement of the trigger. Proper adjustment is critical and has been covered here many times. Look for posts by logman describing the process/checks for correct function.
No, a longer bow is not the correct answer.
Yes, you are blind. They are in there.
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