J frame cylinder latch question

[Malysh]

Will an old style 50s and 60s J frame flat latch work on an early 70s J frame, to replace the newer style cylinder latch?

I noticed the screw head on the old flat latches are smaller across than the screw head on the newer style. Now I'm thinking the shaft of the screws are also different diameters. I haven't pulled the latch off a 70s era one because I only have flat latches. I'm expecting an early 70s Mod 38 and I got this idea of using a flat latch and diamond grips on it.
If this can't work, that's OK, this is just a carry piece.

Thanks in advance.

 

[Malysh]

Will an old style 50s and 60s J frame flat latch work on an early 70s J frame, to replace the newer style cylinder latch?

I noticed the screw head on the old flat latches are smaller across than the screw head on the newer style. Now I'm thinking the shaft of the screws are also different diameters. I haven't pulled the latch off a 70s era one because I only have flat latches. I'm expecting an early 70s Mod 38 and I got this idea of using a flat latch and diamond grips on it.
If this can't work, that's OK, this is just a carry piece.

Thanks in advance.

 

[Smith &W]

I think it will fit because I found out the hard way when I purchased a flat latch diamond grip model 34. When I looked up the serial number I realized it was a 1973 gun. I should have known better.

 

[Malysh]

I just called S&W, they say the screw shaft of a post '66 thumb latch is
also thicker than the screw shaft of the flat thumb latch,and not only at
the head of the screw. It seemed logical to me that if the head of the screw was bigger in diameter, the screw shaft behind it was also bigger in diameter. I wanted to save some labor since my hands are getting arthritic and I try to pick and choose what manual labor I do.

So the early 70s Mod 38 I'm getting this week will stay stock: no flat latch and no diamond grips on it! It does have the pinned bbl. and looks terrific in the pics.

 

[Alk8944]

Malysh,

Don't know who you spoke with at S&W, but he gave you only partial information. It doesn't change the fact you cannot interchange thumbpieces from a flat latch to the later style, but here it is. The flat latch thumbpiece is retained by a screw which enters a tapped hole in the bolt. The later style has a threaded stud which is integral to the bolt and the thumbpiece is retained by a blind nut with a slotted head that makes it look like a screw when assembled. To install a flat latch you would need not only the thumbpiece, but the bolt and screw also. Your idea to leave it alone is excellent.

 

[Malysh]

alk8944,
Thanks for your excellent information!