Tips from the Workbench with Ken Brooks

kenBrooksAGI Gunsmithing Instructor Ken Brooks
is the owner of
 PISCO Gunsmithing in Oregon.

In this video, Ken demonstrated how to determine if your 1911 hammer has positive or negative hammer to sear engagement. A great thing to know for both functionality and safety reasons.


18 Responses to Tips from the Workbench with Ken Brooks

  1. Positive trigger pull in a 1911 results in a heavier than necessary trigger pull weight. The reason is that the trigger is having to use the sear to lever the hammer back against the mainspring, essentially over-cocking the hammer, A properly set up 1911 sear/hammer engagement should be slightly negative.

    • Other may strongly disagree. A neutral of slightly positive sear angle is preferred for safety reasons, especially in a carry gun. I’m sure your comment will generate some discussion from other readers.

      • Though I understand your reasoning I would tend to strongly disagree. I have a few high end 1911’s one of which is a colt series 70 gold cup (original not re-issue). All of them have mighty fine triggers and all are positive. It’s been my experience not only is a negative engagement not a safe condition it lends itself to mushy and inconsistent pulls. At least that’s been my experience. I would encourage you to maybe take a look at how Bob teaches trigger angles in the trigger job videos.

        Another point, I’m no combat vet or anything but if you’ve carried a 1911 (or any pistol) in tactical/practical applications you’ll come to realize you’re weapon can possibly get dropped from time to time no matter how many precautions you take for it not to happen. I have never had one hit the ground and go off. Was it the positive engagement that saved it? Or all the other safeties of the 1911? I don’t know and whether we like to admit it or not stuff like that happens and when it does we want every bit of safety we can get. Just my thoughts.

        As always an excellent video by Ken. I like how well he demonstrated holding the pistol and finding a focus point to observe as well as feel the hammer’s movement.

        • Hi Dan,In reply to your post,I would think it would have to be all the other 1911 safeties,because if dropped the trigger is not even in play.So whether it be positive or negative wouldn’t have mattered.So that’s how I see it,unless I’m on the wrong track.I have Bob’s video on trigger jobs,but I haven’t had a chance to watch it. Have a nice day Rick

      • Ken, This video was great and it reminded me to reach out about trigger jobs on 1911’s. I have watched and re-watched Bob,s video and all makes sense and I believe I understand it. I tried my first trigger job on a new 1911 made in the Philippines. I did not and still do not have the feel for a positive trigger system hence my thanks for your video.
        In the process of doing this trigger job (required because of hammer follow down) I first checked the individual components, out of the gun, using the hammer and sear pins inserted in their holes on the right side of the gun. It turned out that the hammer full cock notch was cut “neutral” or slightly negative. I wound up butchering the hammer and had to replace it. The replacement was cut exactly the same. This time I got it filed reasonably well and all looked good but I wound up having to also replace the heavy trigger. Problem solved but not so much the technique. In Bob’s video he used terms like cut here or bob off there. So my question, finally, is what tools and techniques do you use for cutting the trigger, sear, hammer etc. in doing a trigger job on a 1911? And, in the case of the hammer, do you try to correct the entire cut or just the first 10 thousands? It seems easy to run out of the few thousands you have here and there before you are screwed and/or adversely affect other functions as well. Regards, Bob

  2. As usual a great video. If your 1911 has a positive or negative hammer, what does that tell you? Do you want a positive or negative hammer? If one is better than the other, how do you fix it?

    • I would have to say slightly positive,for safety measures.I would also think that this has to do with the sear and cock notch engagement.I could also be wrong,but that’s how I picture it. Rick

  3. Ideally, the sear engagement angle should be zero 0. The trigger pull should only have to over-come the friction of the metal to metal sear contact. If any angle other than zero 0 a slight 1% positive angle is better than 1% negative.
    In my day, GI surplus parts were cheap and you could ruin your Colt parts and replace them. Smart people fitted the G parts and when they learned how to do it correctly, fitted the original Colt parts.

  4. I just tested my Colt Mustang. Definitely positive which is good for me as my go to EDC.
    I always enjoy your videos they are very educational keep up the good work.

  5. This is NOT a digital argument (i.e. yes or no). One would not want too much positive, but I suggest one should have just maybe 2 degrees of positive engagement, with hard, sharp, well polished edges that engage across the full width. This gives smoothest, crispest, lowest safe pull weight release.

    Works for me, so that’s the end of it for me.

  6. I asked Ken Brooks if he wanted to respond to any of the comments here, especially those saying that a negative trigger is OK. Here is his answer:

    “Pretty sure I don’t need to respond. If they don’t understand that a negative system will wear or allow the hammer to hit and push the sear out of engagement and allow the hammer to fall to the half cock position or worse yet all the way down against the firing pin, nothing I say will change their mind.”

    • Spot on. Had this problem with Browning HP in the Aust Army. Inexperienced armorers touched the sears/hammers and got the angles wrong. Now a hammer falling to half cock is a pain in practice or a comp, but in combat or a defensive encounter it will get you killed. Excellent presentation as always.

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