I have an old model 36 Chiefs Special with a bobbed hammer, and a new 637. Because of the much lighter weight, I'd like to carry the 637. Do these two hammers interchange? I'd like to have the bobbed hammer on the 637.

If your "new" model 637 is new production, then no, the hammers will not interchange. The current models (since around 1997) have a frame mounted firing pin. The older models use a hammer nose (sometimes incorrectly called the firing pin) mounted in the top of the hammer.

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Ret. LE, FA Instr, S&W Armorer

Welcome to the Forum

As mentioned above the odds of your hammers interchanging is not good

However you could always have the 637 hammer bobbed by a competent gunsmith.

Or you could use the short spur hammer that ships with the model 317
Or of you want to keep your original 637 hammer untouched, you could by a second one and have it bobbed.

Early Chief Special revolvers have a different hammer and strut than later guns. Early ones have a ball end on the strut and a matching socket in the hammer, while later guns have a forked strut with a cross pin jn the hammer.

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Tom
1560

Welcome to the forum.

Whenever we talk about swapping parts, it's critical to not only know the Models involved which you supplied, but we need to know the vintage.

The serial #will let us to determine the vintage of your guns, so you can help us help you.

The hammer spring strut has had changes as posted above, but it's an inexpensive part and can be changed also to make other vintage hammers work in different models.

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Jim
S&WCA #819