5th Screw?
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Officially in 1957 for K and N frames (deletion of upper sideplate screw), but 5- and 4-screw frames overlapped for a while.
For I and J frames, 1953 (deletion of the cylinder stop screw).
For I and J frames, 1953 (deletion of the cylinder stop screw).
The first known J-frame model without the 5th screw was the Chiefs Special Airweight. Serial numbers 24002-24008 shipped to the U.S. Marine Corps in Quantico, Va., on October 2, 1952.
The first known ship date for a carbon steel Chiefs Special without the 5th screw was in June 1954.
The first known ship date for a carbon steel Chiefs Special without the 5th screw was in June 1954.
On the K frame, the management directive was issued on September 7, 1956. I believe it was order #486. Order #487, issued at the same time, added a tongue to the side plate to secure it at the top.
This change was apparently implemented fairly quickly, since I own a 4 screw K-38 that shipped in November, 1956.
Was 1957 the same year "soft fitting" ceased?
Yes.
"... soft-fitting department was deleted on May 3, 1957," according to Bill Cross, S&WCA President.
"... soft-fitting department was deleted on May 3, 1957," according to Bill Cross, S&WCA President.
larryofcc
Member
Funny, the 5th screw was not used on the pre m19's, but still used on other K frames past 1957. There must have been a surplus of 5 screw K frames. I always thought it was strange my 1955 Chief was a 4 screw and was sans the trigger guard screw and my 1958 pre M45 had the guard screw and was sans the sideplate screw. Big Larry
On the I and J frames the upper side plate screw is the 4th screw because there was only 4 screws left when it was eliminated from the I and J frames. The 5th screw was the trigger guard screw which was eliminated earlier on the models of 1953 as posted above.
On I frames the first screw to be eliminated was the mainspring tension screw in 1952, which is the 6th screw.
On I frames the first screw to be eliminated was the mainspring tension screw in 1952, which is the 6th screw.
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Larry
I don't think the second part of your statement is true. I am not aware of any K frame revolvers made after 1957 (actually, after 1956) that have five screws. I still own several that left the factory in 1956, 1957 and 1958 that are all 4 screw revolvers and in the past have owned other 4 screw K frames that shipped in that period. The fifth screw went away in late 1956.
As for the Combat Magnum, the first units were assembled in December, 1955, and entered the catalog and AMC in 1956. Obviously management was already anticipating the elimination of the fifth screw, so no Combat Magnum revolvers were ever built on the five screw frame.
larryofcc
Member
Jack, I was going from my poor memory.
I have a HB 5 screw K22, shipped tp Sports Inc. 5-02-1956. Maybe one of the last 5 screw HB wide rib K22's. Shipped with a target hammer and non relieved walnut target stocks. Beautiful high polish blue. Thanks for the correction. Big Larry
I have a HB 5 screw K22, shipped tp Sports Inc. 5-02-1956. Maybe one of the last 5 screw HB wide rib K22's. Shipped with a target hammer and non relieved walnut target stocks. Beautiful high polish blue. Thanks for the correction. Big Larry
I'm ignorant. What is "soft" fitting?
"In soft fitting the frame is fit with a finished barrel, cylinder, and internal parts. The barrel, cylinder and extractor star are stamped with a serial number [barrel and cyl with letter prefix as well]. The gun is disassembled and the small parts placed in a bin and sent to hard fitting. The frame, barrel, and cylinder are sent to polishing then to get a blue or nickel finish."
Roy G. Jinks
Historian, Smith & Wesson
Roy G. Jinks
Historian, Smith & Wesson
Pardon my ignorance, but what was the purpose for the 5th screw? Was it merely another sideplate screw that was placed up by the hammer for sideplate retention, and later found unnecessary? What about the additional "bug screw" that was sometimes found up with the 5th screw? Thanks for any enlightenment that you can provide, inquiring minds want to know.
It depends on what size frame you are talking about. From the way you phrased your question, I think you are asking about the small frames. Jim Carter (Hondo44) is the expert on those.
With respect to the K frame, the fifth screw is actually the one in the front of the trigger guard. It was added in 1905 and deleted in about 1961. Its purpose is to retain the cylinder stop plunger and spring. It 1905, the cylinder stop was modified, requiring that retaining screw. The top sideplate screw (fourth screw) was eliminated in 1956, and replaced with a tongue on the sideplate. The tongue slipped under frame at the top, thus eliminating the need for that screw.
To summarize, before 1905, K frames had only four frame screws, all in the sideplate. After 1956 and before 1961, they had four screws, one in the trigger guard and three in the sideplate.
The sequence was the same on the N frames, except that they were introduced in 1907, already with five screws.
The sequence on the small frames is different, so I'll let Jim explain that.
The "bug screw" you mentioned was only used on small frame revolvers and on some K frame Airweights, if I recall correctly. That is rather outside my area of developed knowledge.
When S&W introduced the J-frame in 1950 (what became the Chiefs Special) it was based on the older I-frame, except the frame and cylinder were larger to accommodate .38 S&W Special ammo.
The J-frame began as a 5-screw. The upper side plate screw was, yes, as you describe it for retention because the side plate was smooth all around the inside and needed that screw to hold it in place.
When S&W introduced the regular production Chiefs Special Airweight in October 1953 it was the first 4-screw J-frame, having lost the trigger guard screw. That was at serial number 24000 in the Chiefs Special series.
The upper side plate screw, although it had a large head, was a short, skinny screw, and repeated use would cause it to back out of the aluminum frame. That upper side plate screw is the bug screw. Dr. Jinks says the assemblers called it that because it was a bugger to install. To hold it in place S&W later added a small retainer screw.
Around Chiefs Special serial number 52600 in early 1955 S&W eliminated the need for the Chiefs Special Airweight's bug screw and its retainer screw by adding a tongue to the top of the side plate.
On December 13, 1955 the company issued Engineering Change #168 to "add a tongue to the top of all I, IT [Target Kit Guns], & J side plates, make the tongue the same as the JA38 [Chiefs Special Airweight] side plate. This will eliminate the bug screw (upper side plate screw) and counter bore and hole." The quote is from Dr. Jinks.
Obviously from Jack's earlier posts you can see the other frame sizes also followed the Chiefs Special Airweight's lead.
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Thanks for clarifying the history of the upper sideplate screw and bug screw. The members of this Forum are an outstanding group of knowledgeable experts, and provide a veritable cornucopia of information!
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