S&W sight screw size?

[rockrat]

Have an L frame gun. Person I bought it from had put a red dot sight on it, but I took it off. Seller sent me the origional sight, but it was missing the front screw on the rear sight, not the sight elevation screw, but the front mounting screw.

Anyone know the size of this screw. I am guessing a #4, but its just a guess.
Any help would be appreciated. Thanks

[MtGun44]

I don't know that specific screw, but I have been repeatedly surprised at the thread in guns.
Most likely it's a non-std thread, and you should probably buy one from Brownells specifically for the
application. Probably not going to find it at the hardware store unless it has a gunsmith section.

Even scope mount screws are 6-48 and the UNC size is 6-32 and the UNF is 6-40 so this super
common screw has a non-standard thread pitch. Pretty frustrating at times.

http://www.brownells.com/.aspx/pid=15421/Product/SIGHT_LEAF_SCREW__REAR__NEW_STYLE

or
http://www.brownells.com/.aspx/pid=15185/Product/SIGHT_LEAF_SCREW__REAR

maybe - - - :-)

Bill

[Bret4207]

I'd contact Gun parts Corp, Jack First Distributing or one of the other parts houses for a replacement.

[Pepe Ray]

6x48

Pepe Ray

[Shuz]

rockrat: I have several Smith 629's and the screw that you mention is of a different size on a couple of them. I suggest you contact Smith Customer Service at 1-800-331-0852 and give them the model and serial number of the gun. Perhaps they will send you one at no charge, or at least for a nominal fee.

[Catshooter]

It should be a 3 x 56. Now what about that size is odd MtGun44? :)


Cat

[MtGun44]

Go down to any regular hardware store and try to find a #3-56 screw with the correct head,
and I'll be quite surprised if you can find any #3-56 (if that is what it is, I have no idea), let
alone one with the large diameter shallow head that the S&W sight requires. Maybe your
hardware stores are better than mine.

Bill

[rockrat]

Thanks

[Catshooter]

Ain't that the truth Bill? It can be truly amazing what thread sizes were used.

Some, like the thread on the 1911 grip screw bushing (.236 x 60) were just out of nessesity. Others, like the 10 x 36 on older Lyman/Ideal sprue plate were just a handy size.

A lot were used prior to the USA going to standard thread pitches, like the Lyman. And actually a 3 x 56 is a standard size here in America. But standard doesn't mean the same as common, that's for sure.


Cat

[deltaenterprizes]

It is a #5, but I will have to check the pitch.

[Sprue]

I would consult the local Pawn Shops.

[KCSO]

tiny ?

[imashooter2]

Have you called S&W?

[MtGun44]

Sorry for the thread drift . . .

I was restocking a Savage falling block .22, needed a headless bolt to fit the buttstock to
the receiver. Unscrewed the bolt under the butt plate and removed the screw. 5/16"
diam, check the pitch? Coarse is 18, fine is 24, this one is . . . . . . . 20 threads per inch!

What the heck?

I had to fire up the lathe to make a alignment rod to fit the buttstock.

Weird!

Bill