Is hammer mass critical

[twin oaks]

I was wondering if the mass of the hammer is critical. Reason? Instead of replacing my GS and hammer on my colt 1991a1, could I 'modifly' the existing hammer? Specifically I'd like to round some of the edges, just a little, to keep 'em from poking me in the love handles. ( And don't tell me to just lose weight.)

Now if I can just remember where I left that Dremel....

[1911Tuner]

I was wondering if the mass of the hammer is critical. Reason? Instead of replacing my GS and hammer on my colt 1991a1, could I 'modifly' the existing hammer? Specifically I'd like to round some of the edges, just a little, to keep 'em from poking me in the love handles. ( And don't tell me to just lose weight.)

Now if I can just remember where I left that Dremel....

Not so critical that it can't be melted a bit to reduce the abrasions to your skin.

[OD*]

could I 'modifly' the existing hammer? Specifically I'd like to round some of the edges,
Old school .45 dudes have been doing that very thing for years. Just don't get carried away with that Dremel! :p

[Lazarus]

Twin Oaks, you have hinted at a potentially very interesting subject. Go ahead and remove the sharp corners - that's the short answer. Just for fun, however, it would be interesting to have some input from a physics whiz on this subject.

The functional requirement is for the hammer to deliver sufficient energy to the primer for reliable ignition. The energy delivered through the firing pin is dependent upon the instantaneous speed of the hammer as it hits the firing pin, as well as the mass of the hammer (you assume the hammer decelerates to 0.) With a little consideration, you will see that if you reduce the mass of the hammer, (keeping the same mainspring), it will accelerate more quickly and arrive at the firing pin with a greater velocity than a heavier hammer. So, will the energy delivered be greater due to the greater hammer velocity, or less due to the decreased hammer mass, or the same (not likely)?

The actual energy delivered is going to be a complex function that no doubt shows that some particular hammer mass will deliver an energy peak that falls off a bit when mass is added or removed from the hammer. I don't think we need to understand the problem at this level, but it is nonetheless interesting to consider. Those shooters who believe that lock time affects their accuracy, will want skeletonized hammers and titanium firing pins. They're lighter, but they also accelerate more quickly. The original parts accelerate more slowly, but strike with more mass. Finding out exactly what is going on gets involved very quickly. Luckily it usually does not affect reliable primer ignition one way or the other unless you are at one of the extremes. Just having some fun.

-Lazarus

[CreapyCrawler]

If you look at the hammers on some Sigs and Kimber Compact they vertually have no hammer spur. I don't know how you manually cock or lower the hammer. Is there something else done to these like heavier spring?

[Hawkmoon]

Just for fun, however, it would be interesting to have some input from a physics whiz on this subject.

The functional requirement is for the hammer to deliver sufficient energy to the primer for reliable ignition. The energy delivered through the firing pin is dependent upon the instantaneous speed of the hammer as it hits the firing pin, as well as the mass of the hammer (you assume the hammer decelerates to 0.) With a little consideration, you will see that if you reduce the mass of the hammer, (keeping the same mainspring), it will accelerate more quickly and arrive at the firing pin with a greater velocity than a heavier hammer. So, will the energy delivered be greater due to the greater hammer velocity, or less due to the decreased hammer mass, or the same (not likely)?

Actually, as a washed-out one-time Physics major my opinion is that your third choice ("the same") is correct. Mass of the hammer isn't important.

Why? Because where does the kinetic energy originate? In the mainspring. Whatever energy is in the mainspring is transferred into the hammer, and from the hammer into the firing pin. As you pointed out, the lighter hammer will accelerate faster. Energy equals mass times acceleration. If the only part of the system that gets changed is the hammer (mainspring, firing pin and firing pin spring remain the same), the energy transferred through the system will remain the same.

[niemi24s]

From one one-time washed out physics major to another, I have dim (very dim) recollections of:

Force = Mass X Acceleration, and

Energy = 1/2 X Mass X Velocity X Velocity

[Read the second one as " e equals one half m v squared] If the second one's true, if a mass reduction of, say, 5% somehow results in a velocity increase of 5%, the energy will be greater cuz velocity's squared - I think.

Remember, pi r square? No - pie are round!!

[baldessariclan]

"[Read the second one as " e equals one half m v squared] If the second one's true, if a mass reduction of, say, 5% somehow results in a velocity increase of 5%, the energy will be greater cuz velocity's squared - I think."

Speaking from my perspective (as an enginerd), I'll betcha that a 5% decrease in mass of the hammer probably results in a less than 5% increase in speed of the hammer (or is that the other way around? hmmm...), because the amount of driving energy delivered (from the mainspring) remains exactly the same. Conservation of energy, right?

Just a thought -- fun discussion!

--John

[lanceriley]

any more? it's getting interesting.. recalling the physics stuff. how do you measure the speed of the hammer?

[niemi24s]

.. is the title of an article by Alton S. Dinan, Jr, in the July 1970 American Rifleman. Dinan mounted a 1911 on a lathe to measure the fall times of three different hammer styles and got:

287.9 gn wide spur hammer = 0.0057 sec,
281.1 gn standard hammer = 0.0047 sec, and
201.0 gn speed hammer = 0.0037 sec.

Comparing the top & bottom hammers, for a 29.9% reduction in hammer weight/mass Dinan got a 35.1% reduction in fall time. As the hammers probably fell/rotated about the same distance, the lighter one would have to have been accelerated faster by the mainspring to get there quicker. And don't forget that for a rotating body its moment of inertia depends on how far its center of mass is from its center of rotation (as I recall).

As my head is starting to throb, I'll leave the questions of "how much faster?" and "how much more energy?" to somebody who really knows something about this stuff.

[John]

I am not physist (just a chemist and computer nerd), but I've bobbed a spur hammer once, it had half the spur when I was done with it, and it still fired fine. Another example, look at the Para LDAs. No spur at all. I haven't weighted their hammers, but I bet you they are quite lighter than a spur one.

[AV8R]

Well, I'll bite, too. As I recall, the 1911 has a floating firing pin, which needs to be considered in the analysis, and that is a good place to start. Now the problem can be defined: How do you couple the most energy, which is stored in the mainspring, into the firing pin? Starting with the basics, two things have to be conserved: momentum, and energy. Since physics is basically all talk, the calculations being relegated to the category of applied mathematics, we'll stick to all talk here.

In step 1, the mainspring is compressed, storing energy U. In step 2, the hammer is released, and acquires a momentum of Iw and energy Iw^^2, where I is the moment of inertia of the hammer and w is the angular velocity, or speed in units of angle per second. Neglecting friction, of course, the final energy or the hammer just before impact equals U. For a rotating system, the quantity "Iw" is called "angular momentum", and is analogous to momentum in the non-rotating case, or just mv. In step 3, the hammer hits the firing pin, and transfers most of its energy, and its momentum to the firing pin.

The problem is to juggle the moment of inertia of the hammer and the mass of the firing pin so that the maximum energy of the mainspring goes into the firing pin. In the linear case, maximum energy transfer happens when the driving mass and the driven mass are equal. This is what happens when you set up two snooker balls on the rail a few inches apart, and shoot the cue ball into the red ball. Assuming no English, the cue ball stops dead at the instant of contact, with all the energy and momentum going into the red ball. If the cue ball was heavier than the red ball, less energy would be transferred to the red ball, and the cue ball would follow. If the cue ball were lighter,it would bounce back, again transferring less energy to the red ball. Likewise, there will be a moment of inertia for the hammer, I, which matches the mass of the firing pin ,m, and will transfer the most energy.

By the way, I'm a believer in the lock-time thing. Way long ago, I put a titanium striker in my G17, and my groups shrank to about half. I'd sure like to know if anybody has had a similar experience with their 1911, as it's really tempting to go that way with my Springer. Problem is, I'm not a good enough shot that I think I could necessarily notice a difference.

[John]

I'm a believer in the lock-time thing. Way long ago, I put a titanium striker in my G17, and my groups shrank to about half. I'd sure like to know if anybody has had a similar experience with their 1911, as it's really tempting to go that way with my Springer. Problem is, I'm not a good enough shot that I think I could necessarily notice a difference.

If you manage to shrink your groups to half by the titanium striker, you are a much better shot than I am. Some years ago, I went to the extreme (at that time) replacing any possible part with a titanium one (hammer, hammer strut, firing pin, everything that was available). I didn't notice any difference in my groups, I am sorry to say.

[A.B.]

http://i163.photobucket.com/albums/t316/gordonsorensen/Annex-ThreeStoogesThe_06.jpg

[niemi24s]

John: You mean you didn't try the Tactical Titanium Torx-Drive grip screws?

:lm:

[I just figured out how post smilies]

[AV8R]

If you manage to shrink your groups to half by the titanium striker, you are a much better shot than I am. Some years ago, I went to the extreme (at that time) replacing any possible part with a titanium one (hammer, hammer strut, firing pin, everything that was available). I didn't notice any difference in my groups, I am sorry to say.

It surprised me, too. I changed the striker spring as well, and the combination added a lot of smoothness to the trigger, also. It went from a strong "clack-buzz" to a smooth "click-'ts". I don't know which had more effect, though, the lock time or the smoothness. However, it's not likely that I'm anywhere near as good a shot as most of the people on this forum, but the change was very noticeable. I think it's possible that Glocks, which have always seemed a little "shaky" to me, might respond better than the more highly-damped 1911s, though.

[OD*]

As I recall, the 1911 has a floating firing pin
I don't believe so, Winchester model 94s, AR15/M16 etc., have floating firing pins (no firing pin springs).

[AV8R]

I don't believe so, Winchester model 94s, AR15/M16 etc., have floating firing pins (no firing pin springs).

Right, I may have used the term incorrectly. I was trying to make the distinction that the firing pin was a separate piece from the hammer, and did its own thing after being struck.

[OD*]

Gotcha amigo. ;)

[brickeyee]

The 1911 firing pin is an inertial pin.
It has zero protrusion past the breech face when the hammer is fully down and the head of the pin is flush with the firing pin stop.
It is the inertia imparted to the pin that carries it forward to actually strike the primer.
It is never in contact with both the hammer and primer at the same time.

[John]

It surprised me, too. I changed the striker spring as well, and the combination added a lot of smoothness to the trigger, also. It went from a strong "clack-buzz" to a smooth "click-'ts". I don't know which had more effect, though, the lock time or the smoothness. However, it's not likely that I'm anywhere near as good a shot as most of the people on this forum, but the change was very noticeable. I think it's possible that Glocks, which have always seemed a little "shaky" to me, might respond better than the more highly-damped 1911s, though.
If the changes improved your trigger pull, that's where your grip shrunk from, not the lock time.

[AV8R]

Just out of curiosity, do any of the gun or parts manufacturers who use the forums have the mass and "I" values for their hammers? It might be interesting to model the behavior of the gun for different hammer, spring, etc. combinations.

[AV8R]

If the changes improved your trigger pull, that's where your grip shrunk from, not the lock time.

In retrospect, that probably accounts for most of it. It certainly seemed to me to be worth the money, though, based on the general improvement in the feel of the gun as well as the shooting.

[David Rose]

My suspicion is that faster lock time would help a less skilled shooter more than a better one. This is theory again, with little basis. I have never spent the time to hone my shooting skills like I should. Any little change improves my scores. Or is that like a placebo? Maybe I just focus better after making the change? :o

One of the best shooters at our little gun club (years ago) was an older guy who shook so badly that he had to give up his job as a business machine tech. Poor Jim could not hold a screw driver well enough to drive a small screw. :( But he could still shoot. Shaking hands with Jim "hurt". His shaking went all through your body.

My first trip to the informal club range, I met Jim. Jim shot well with an old High Standard (non Victor). The rest of the guys had Smith 41s and HS Victors. I was embarrased to uncase my little Ruger Standard. I finally did. Jim watched me shoot for a minute, then asked if he could shoot my gun. Of course, I desired to learn all I could, so he shot it. He cut out the Xs and 10s and handed it back to be. He said "nice gun". I knew he was trying to be a "nice guy" with the comment. He had also shot a better score with that little cheapie which had a horrid looooong trigger pull than anyone else was doing with their high end 22s.

A couple of days after that shooting time, Jim came into our shop. I cornered him and asked him his secret. At the range he had already showed me how to "circle under and around" the bull. Jim said "no secret. It's all in knowing *when* to pull the trigger."

My suspicion again, is that the better the shooter, the more control he has of any gun. I'm sure when it comes to counting high numbers of Xs, the pros can benefit from a better system. But I'll bet that my scores will improve much more than theirs. Of course, mine will be having to add numbers instead of counting Xs. :D

David

[twin oaks]

Well this certainly stirred up the proverbial hornet's nest. My initial question was answered very succinctly by Tuner. Thank you. As for the lock time questions, and the precise physics, I'm still catching up. However, being the gerd that I am ( geek+nerd) I'm aware of mass times velocity, etc. I posed the question because of energy transfer of the mass of the firing pin in direct relation to the mass of the firing pin PLUS the firing pin spring's resistance to compression. All that just to overcome the inertia of the FP.But yes, a lighter hammer should travel faster, and I'm thinking weight reduction in fractions of grams, not half of the hammer. Possibly just doing a 'melt' like Tuner suggested.
Thanks to all for your input.

Niemi, you are correct pi r round, cake r square. ( Dad and I have been saying that for years.)

[twin oaks]

Oh, I forgot to mention: I've learned enough on this forum to leave the dremel in the barn. I'll do the mods with a fine mill file and polish the edges with a diamond lapp. A little here, a little there, and maybe a little rebluing.
Other important things: After a trip to the range yesterday, when I stripped it for cleaning, I noticed a burr on the front of the left frame rail. A tiny one, just enough to hang on a finger. I was firing Rem. 230 fmj rounds, and recoil didn't feel excessive. Is it new spring time? As far as I know the pistol has less than 2000 rounds through it, and almost all of my previous shooting has been handloads. Two swipes with a fine file eliminated the burr, and I worked around the side and front of the rail to make sure. So, it wasn't much of one, but is was there, and I think it was caused by overtravel of the slide.
Suggestions?

[niemi24s]

The aft travel of the slide should be limited by slide dust hood/recoil spring guide flange/receiver web contact. Check the front of the corresponding groove in the slide - could be something in there causing the bur on the frame rail.

Also, make sure you're using the proper strength recoil spring. Regards.

[George Smith]

The 1911 firing pin is an inertial pin.
It has zero protrusion past the breech face when the hammer is fully down and the head of the pin is flush with the firing pin stop.
It is the inertia imparted to the pin that carries it forward to actually strike the primer.
It is never in contact with both the hammer and primer at the same time.

Um...... Well not exactly. Once upon a time there were guys running around with guns that held many bullets, and these bullets were tiny ones. But the pressures got a little carried away so the primers started to flow into the firing pin hole.

There was a cluster of peeps from the great lakes regon Clark, Vanderbus and Barnheart took to cutting the firing pin stop down so the firing pin would protrude. than they pulled out the main spring housing cap pin so the strut could come up higher.

We came out with a longer firing pin that when hit by the hammer actually stuck out and prevented primer flow.

stock firing pins travel about .040 iirc before they start to hit the primer so probaly 1/16 till ignition.

So for the quick fire deal
Longer firing pin to lessen travel to ignition. (not Ti which contributes to primer flow)
lighter hammer ( and the all important strut location on the hammer)
Ti strut (travels a good distance)
Ti Cap with short tail easily under half the weight of stock.
Not a wimpy main spring.

not sure what it would measure but the time from sear release to ignition would be reduced.

geo

www.egw-guns.com

[David Rose]

Uh, oh! Second post and I'm a "hornet" already. Sorry. Didn't mean to wander this far from the nest... er... subject.

David

Well this certainly stirred up the proverbial hornet's nest. My initial question was answered very succinctly by Tuner. Thank you. As for the lock time questions, and the precise physics, I'm still catching up. However, being the gerd that I am ( geek+nerd) I'm aware of mass times velocity, etc. I posed the question because of energy transfer of the mass of the firing pin in direct relation to the mass of the firing pin PLUS the firing pin spring's resistance to compression. All that just to overcome the inertia of the FP.But yes, a lighter hammer should travel faster, and I'm thinking weight reduction in fractions of grams, not half of the hammer. Possibly just doing a 'melt' like Tuner suggested.
Thanks to all for your input.

Niemi, you are correct pi r round, cake r square. ( Dad and I have been saying that for years.)

[1911Tuner]

Well this certainly stirred up the proverbial hornet's nest.

Nah. Sometimes these discussions just sorta evolve and fly wide of the original
theme. Sometimes they go off on a tangent, with more noise than signal...and sometimes we can pick up some interesting and useful information. The trick is in bein' able to separate the wheat from the chaff. Differences in lock time and the hammer's striking energy is one of those subjects that sorta naturally enters the discussion whenever alterations to the gun's trigger group/fire control group comes up.

[twin oaks]

'K thanks, I'll recheck the slide for anything causing FOD.
Tuner, after reading the threads here for the last 6 months ( before joining), I understand. As I learn more about this pistol, I want more and more to pick up another one to tinker with. Something keeps nagging at me to leave the Colt alone, keep it stock, and do my experiments on a 'beater' as you call them. I think we've fairly well answered the call of this post, and I appreciate everyone's input. I'll save my other questions for another post, one more aptly titled, and in the correct forum.

Thanks to all.