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Can I carmonize this hammer?


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I’ve been doing some searching about bobbing my hammer and doing an action job on my 627-4 PC over the last couple of days.

I took my gun apart to have a look and the hammer looks different to all the examples I have seen.

Most hammers look like this one where there is a significant cut out on the side facing us. My hammer is completely flat on this side with only a small dog bone shaped cut out on the other side for the trigger lock.

Why is it different? Should I/Can I still hack away at it?


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"Everybody's talking at me.....I don't hear a word they're saying.....only the echoes of my mind....."

(Lose the spurs, Hoss.)

You do have a certain "John Voigt" quality now that you mention it.

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  • 1 month later...

what is the point of removing the spur?

Like using a commander hammer on a 1911, some hands interfere with the hammer spur when riding as high as possible. Also trimming the spur and extra metal from the hammer allows for a lighter action. It seems in CF Revolvers that the lighter the hammer, the quicker the strike and the more reliable the ignition. I'm sure there is a point of diminishing returns though.

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I'm sure there is a point of diminishing returns though.

Since the OP used a pic of my 625, I'll chime in ;)

Reducing hammer mass by Carmonizing, or even just lobbing off the spur reduces the hammer's inertia (inertia is really the big deal, but we use mass as a proxy). A hammer with less inertia travels faster when pushed with a spring of the same energy. Any object that travels faster while transferring the same energy delivers more power, and it's power (not energy or momentum) that lights off primers. A gun with a low-inertia hammer can be tuned lighter before reliability becomes an issue, then. And while it delivers more power (a good thing), it delivers less momentum as well. Since it's momentum that jars the muzzle upon hammer strike, a low-inertia hammer seems like a win/win.

Diminishing returns? Yep. First, less momentum also means the low-inertia hammer has less ability to overcome internal friction. Below some mainspring threshold then, reliability will quickly tank. Where exactly that threshold is will depend on how much internal resistance there is inside your gun. Lightening the hammer, then, is best done as part of a good and complete action job to insure than everything inside is smooth, straight, centered and plumb.

There's another element to "diminishing returns" that's very subtle, and I've not yet seen discussed anywhere: The Sweet Spot. Any percussive rod (tennis racket, baseball bat, etc) has a sweet spot - hit the ball there and the ball just sails, and it "feels" right in your hand. When the sweet spot is hit, the forces at the pivot cancel out, and all the force is applied to the ball. Miss the sweet spot, then, and the ball thuds, and your hands sting. The location of the sweet spot isn't accidental. It's very intentionally put where it is, so the precise shape of the racket and bat is highly engineered. It's no different with a revolver hammer.

Some months ago, I was curious to see if the sweet spot on a revolver's hammer could be improved. My thinking was that the shape of the revolver hammer is simply what'll fit into the frame, so the sweet spot couldn't be right, right? Wrong. Determining the sweet spot requires actually measuring inertia, which isn't trivial, but I'll be damned if I didn't find the sweet spot for a revolver's hammer is exactly at the firing pin (same for a 1911 and CZ hammer). huh. What's more, the precise shape and mass distribution of the hammer seems to be what's needed to get the sweet spot there. IOW, anything you do to change the hammer's shape and/or reduce inertia will move the sweet spot away from where it needs to be. My conclusion is that the precise shape of a hammer is very intentional, and it's not just the shape that'll fit in the gun. Those engineers really thought that hammer out, it seems. So, what's the diminishing return? Trim the hammer, and you move the sweet spot, and the force being applied to the primer is being robbed to apply force to the hammer pivot pin. How much does this matter? No idea, but I suspect it's another reason why reliability will quickly drop once some lower mainspring threshold is crossed.


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Thanks for the informative post, Tom.

The "sweet spot" makes sense. Removing material below and leaving some mass at the point of contact could induce some flex, which would increase energy transfer. Kinda like a modern golf club.

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