Not too long ago when I first obtained by Georgia weapons carry license I purchased a SW 637 as a carry. I read about the hammer snagging but I thought it would not be a big deal. I was wrong. I know the trick about thumbing the spur, but in truth I didn't want to worry about it if the time came. So I purchased a 642, and since then have also purchased some 640's for carry. I thought about selling the 637, but I have this strange habit of developing attachments with inanimate objects, guns especially. So with my Model 642 and 640's to keep me occupied, the 637 lay neglected in the safe.
The 637 is not a range toy, so it seemed like such a waste to let it languish. So I decided to bob the hammer and see if I could salvage the 637 as a carry. I must say the job was quite easy (with a dremel and a vise, of course). It took about 1 hour start to finish - including disassembling, cutting, grinding, polishing, blueing and reassembly. I like the results so much I think the 637 may take the place of my 642. (The timing may be perfect, as my wife has decided to get her carry license as well and the 642 may end up being hers).
Here are some pics of the result. What I like most about the bobbed hammer is that that profile of the 637 is slightly smaller in height than that of the 642 at the backstrap.
Bobbed 01.jpgBobbed 02.jpgBobbed 03.jpg
The second picture is a picture of the bobbed hammer as the trigger is being pulled. I bobbed the hammer so that it is flush with the frame when the firing pin is fully engaged, and it rebounds slightly when at rest. I may grind it down a bit more - but that would be merely cosmetic, as I have been unable to snag the gun on my clothing now.