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Discussion Starter #1
I have begun attempting to learn the details of action component matching.
I purchased a high quality hammer and one 'precision' hand adjusted. The differences between them have me puzzled. The hammer hook surface : should it be parallel to a radial line from the hammerpin axis (as one is) Or, parallel to a line drawn from the 'inside edge' of that hole (as is the other) ??

Thanks,
 

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This is going to get interesting. I've never heard the hammer hook dimension expressed the way you did. Were I to answer the question directly, I'd say the answer to both is "no." The 90 degree refers to the angle from the ledge where the hooks start. If the hammers you have are quality commercial ones, the hooks are probably right on already. Military hammers, and lots of copies, have the hooks finished at an "over 90" angle and have to be trued up prior to custom or match use.
Hope this helps.
Bob
 

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Discussion Starter #3
Here is a perhaps, exaggerated idea of what I am attempting to describe :
http://www.evcom.net/~apettit/hammerhooks.jpg

In each, there is a '90degree' angle between the flat and hook, but the points of rotation make one hammer break clean, the other causes the sear to lift the hammer slightly during its slideout..

Regards
 

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I understand. That's called negative deflection and is undesirable in a trigger job. It can lead to doubles and even full auto fire. The opposite is positive deflection, where the hammer will move slightly downward, toward cocking, and that's also undesirable though not dangerous. It just causes a heavy pull. I just re-read your post and it looks like I reversed the deflection. Anyhow, you get the idea.
I must admit I've never thought of hammer deflection based on anything having to do with the pin axis. It usually is caused by the angle on the sear crown.

I like your graphic on this thing. Wish I knew how to do that...and do it that well!!
 

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Discussion Starter #5
Hello Bob,

Well, my first hammer hook stoning created an edge that 'points' not quite to the edge of the hammer guidepin hole. The idea IS : just making a perfect 90 degree edge with respect to the machined flat on the hammer will not necessarily create the same performance.

All 90degrees are not created equal !

Best Regards
 

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I was wondering about this a few weeks ago myself. Not that I wanted to "fit" a new hammer or anything. I had noticed that the 90 degree term seemed to apply to the angle between the flat on the hammer and the hooks themselves. I also noticed that a line drawn from the hammer hooks did not go through the axis of rotation at the center of the pin hole. Seemed to me that the sear would have to push the hammer out of the way in order to break.

To better understand how the heck a good trigger worked, I assembled the hammer and sear along the right side of the frame with the respective pins and then looked at the interface between the hammer hooks and sear with an eye loupe. As it turns out, the flat surface of the sear sits on the outside corner of the hammer hooks. The smoothness of the trigger break has more to do with the flat surface of the sear being parallel to the arc of rotation of the sear and not so much to do with the angle of the hammer hooks. Very interesting approach.
 

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Yes
do the same with the sear.
make the sear flat corrolate with the center of the sear pin hole at a 90 degree angle.
(like your Right side picture.)

the (huning)koenig hammer rotated the flat around the hammer pin hole. to point more twards the center.(not to the center) If you cut the sear at a nutural angle (so as the sear comes out of the notch the hammer did not move forward or backward) You still want the tip of the hammer hook to hit the flat (about .018 in from the edge
) of the sear.
that is why the sear must be pretty hard. the hammer over time puts a dent in the sear. (with a good sear it can take 10,000 for the dent to show up)
(with Ti hammers the hammer formed to the sear that was another problem)

the Behlert hammer made the notch point directly at the center. Like Bob said under 4# this lead to doubling and full auto fun.
So that part did not work well that way.

If your trickey, instead of following the 90 degree line, just go to 92 or 93 degrees to flatten out the contact. If it is dead flat it will probably have trouble, just sneak up on it.

geo ><>
 

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Well spank my butt and call me happy.I've been doing that and all the local 'experts' kept saying it's taboo to cut the hammer hook above 90.My style has been like George's.Set your sear to come straight out from under the hammer and mate the hooks to the sear.I have to say that one of mine is just about a perfect match and haven't had it slip yet-but it also doesn't have 1000rnds through it yet.Thank you Mr Smith for another reinforcement of my technique.
 

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Have any of you guys seen one of Jim Clark's old 1911's? He started his shop the same year I did and he used to do great trigger jobs. We disagreed on one critical area but I couldn't knock success. Jim would reduce the hooks to 018 all right, but he'd "round-off" the sear crown so it would miss the corner of the hooks and not indent. It would then just slip out from under the hooks when the pressure reached the proper weight and go bang. He stopped doing that after a few years, probably because it was time-consuming and tricky to do, but it sure worked for him.
About the only concesion I make now to that system is the round edge I put on the corner of the hooks. It delays that dent in the sear for quite a while.
 

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Bob,
I also stone a radius of approx. .003" on the top corner of the hammer hooks.
Combined with contouring of the hammer face for minimal overcock, it promotes indefinate life of a trigger job.
The latest rage, is altering the geometry of the hammer to facilitate 'drop-in' trigger jobs. I think McCormick was one of the first to do this. Thankfully Wilson has stayed with the original Colt geometry.
Take a Wilson or Colt hammer and compare it to a Kimber or Ed brown 'perfection' hammer. Use the hammer pin through both hammers, align the hammer hooks, and you will see what I'm speaking of.

Chuck

[This message has been edited by pistolwrench (edited 09-17-2001).]
 

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Hi Bob and Chuch

I also round off the points with a ceramic stone. I do a less than .005 though. probably depends on how high your hooks are to start with.
geo ><>
 

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Geo,
I just edited my post to read .003".
I'm sure that is closer to reality than the .005" I originally stated.
I normally first machine the hooks, with a new carbide end mill to a height of .021".

Chuck
 

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Ok,now I'm confused.I thought the Wilson(or at least the Ultralite) was patterned after the Gold Cup with the higher hooks and lower strut pin hole.
 

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This pic should illustrate the 'altered geometry' I spoke of earlier:



The hammer in the foreground is a 'prepped' Wilson Ultralight.
The hammer in the background is unaltered and from a recent vintage Kimber.
Both hammers are mounted on a common axial pin thru the hammer pin hole.
The hook faces are in each case, cut at a 90 degree angle relative to the 'hook floor' directly in front of the hooks.

The Kimber and other similar hammers appear to have the hooks and floor rotated 8 degrees or so to the 'rear', so as to hold the sear, regardless of sear face angle, less captive.

I have never had much luck in getting a dead crisp trigger break on a Kimber style hammer, that would stand up to hard abuse, such as allowing the slide to SLAM forward on an empty chamber without dropping to half-cock.

Maybe I am too picky, but when I state 'dead crisp' that is exactly what I mean. No slip, no roll, just SNAP.

Cheap-Fast-Good
Pick any two.
 

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Discussion Starter #18
Hello PistolWrench and All,
as shown before , http://www.evcom.net/~apettit/hammerhooks.jpg
The diagram on the left, and the start of this topic Was an EdBrownPerfection hammer.
I had never before heard anyone detail hammer hook design prior to this discussion.

I was attempting to install an EdBrown set (and learning also) in my new KimberEclipse. I used a BrownellMarvel tool. The first try felt pretty good, but the slide did not push back the hammer sufficiently to engage the sear. After shortening the sear about .01" ( as recommended by a gunsmith who is being entertained by my mistakes ), the hammer cocked, but followed through to halfcock when dropping the slide. I did that 2 or 3 times, and then disassembled. The halfcock catch was so hard that the sear pin bent and the sear surface was damaged. I have ordered a new sear and pin and will try again. From your posts, I am considering reworking the EdBrownHammer to have the hook surface on a radial to the pin. And, I plan to put a piece of soft plastic in the halfcock catch to prevent sear and pin destruction if the hammer drops through again !

Greatly Informative Thread

Regards
 

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Southgun
I would not recomend you put a soft piece in your trigger mech. If it comes out it will cause problems. If the sear pin bent that is a bad part. Peroid. (seeing this more on ser 80 parts as the cut out for the lever leaves the pin less supported)

Chuch ditto on the trigger with the mim parts for me also. We also use a fresh carbide endmill to square up the notches. I "think" if the hammer notch is flat to the sear crisp will not happen. I also think close is good as the point will be stronger. close but not flat. On the Koenig hammer we grind the notch and at 53 rc they are hard but not toooo hard.

geo ><>
 

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Discussion Starter #20
I only intend to use some added safety during my adjustment period to help prevent destroying more parts.

I believe that just flat surfaces is not the solution but to have that surface perpendicular to the rotation of the two parts in that hammer bounce will not tend to push the sear out, nor will the sear need to lift the hammer during its release.
 
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