Change extractor rod, right to left hand thread

[65Whelen]

I've seen references to the change from RH to LH threads on the extractor rod and that there is a visual tell on the rod. Can someone explain this or better yet pictures of the difference.

 

[cruiserdan]

The knurled tip at the end of the rod is the telltale. If it meets evenly with the rod it is right-hand thread. If there is an undercut shoulder between the knurling and the rod it is a left-hand thread.

 

[JP@AK]

First, this applies to K and N frame revolvers only.

Starting in 1959 (a bit later on some models), S&W changed the threads on the extractor rod to left hand threads. The right hand threads had a tendency to back out under recoil. The change was made to resolve this problem.

On revolvers with the new left hand threads, a smooth space (it could be called a "groove" or a "gap") was machined into the rod just aft of the knurled portion at the end.

This picture shows a revolver with right hand threads. There is no gap between the knurled portion and the rest of the rod.

This picture shows the gap on a revolver with left hand threads:

 

[65Whelen]

Thank you, that answers my question. You guys are great.

 

[Hondo44]

Thank you, that answers my question. You guys are great.

Just FYI so there’s no confusion: none of the above information applies to I and J frames.

When I frames were reintroduced after WWII they were given left hand threads.

When the J frame began life in 1950 it had left hand threads.

 

[JP@AK]

Just FYI so there’s no confusion: none of the above information applies to I and J frames.

Jim is absolutely correct. That's why I started my post this way:

First, this applies to K and N frame revolvers only.

 

[Hondo44]

Jim is absolutely correct. That's why I started my post this way:

Jack you did make it perfectly clear!

I only added the I and J frame info for the benefit of readers who might be curious about how they differ. I should have worded it differently.