Top break latch?

[coyotejoe]

Howdy, been away for a while but I knew this would be the place to get an answer. My question is in general regarding the design of the top latch. I've become interested in the small pocket pistols of the late 19th and early 20th century. Most of these are break top designs and most of the latches are of the inline design which I consider a very poor design since the latch itself must take the thrust of firing. I've always thought a much better design had a mortise in the extended top strap to close over a raised stud on the standing breech so that the latch need only hold it down. That makes a lock up as strong as a solid frame. Examples would be the Scofield and the Webley revolvers. Some few American top breaks also employed this design. I see that the S&W Safety Hammerless had a similar latch at one time but by far the most employed the common weak inline latch. I'm wondering which models employed the stronger latch setup?
I've attached a photo (if it works) of a cracked latch and bent latch screw from a cheap top break which shows the weakness of that design

 

[Wiregrassguy]

Welcome to the forums from the Wiregrass! I can't answer your question but I'm sure someone will be along shortly who can.

 

[coyotejoe]

Thanks for the welcome. From what I'm seeing on internet photos there appear to have been at least three different latches tried over the several generations of the Safety Hammerless.

 

[mmaher94087]

The 1st & 2nd Schofield, 1st .38 Safety and the 1-3 .32 Safety come to mind. After those, the latch was (as you describe): in-line

 

[glowe]

I have owned many top-break S&Ws and never had a problem with any top latches, but I try to buy only solid lock-up, not abused guns. They have remained that way after all have been shot at the range many times over the years. The system must have been quite effective for S&W, since all Americans, Russians, Schofields, New Model 3s, 44 Double Actions, plus 32 Single Action, 38 Single Actions, 32 Double Actions, 38 Double Actions, 32 Safeties, 38 Safeties, 38 Perfected revolvers, and Single Shot Target pistols had top latches.

As for the types of locking mechanisms found on Safety revolvers, there are two different latches found on the 32, with the first being a push button rear latch that was changed out to a standard top latch around 1902. The 38 Safety had four changes made to the top latch over its production range. The first was called the "Z-Bar" which utilized were two different push button designs found on the sides of the top latch, there were also two types of push button latches on the 2nd & 3rd Models, and finally a standard top latch was adopted in 1898 with the 4th Model.

Can these latches fail, absolutely - but it takes deliberate abuse or over-pressure loads to break them in my opinion. Remember that these guns made the transition from black powder to smokeless with no changes in design, but when owners made that same change while reloading, the results could have been parts or gun failures. It was not an uncommon mistake to load early smokeless powders the same way as reloaders loaded cases with BP, fill the case with powder, leaving just enough room to seat the bullet. Obviously, if the gun did not blow up, parts would have been stressed beyond any normal limits.

 

[coyotejoe]

Thanks, that is exactly what I wanted to know, you guys are a great bunch.

 

[steelslaver]

Actually I think the top break latch mechanism is fairly strong. Look at heavy machinery chain. You can harness alot of horsepower with multi row chain. I once ran a drilling rig with 3 398 Cats (V12s) and they were linked together and to the draw works with machinery chain and that rig was rated to lift 1 million lbs. The pins on that roller chain were only about 1/4" in diameter, but 4 to 6 links wide depending on location. A top latch has 3 points similar to 2 link wide chain and even my little 32s use about a 1/8 pivot. My 44 Russian has a slightly larger pin, bigger posts and the "links are heavier. As long as the lock up is tight and in line it can take a pretty good load. Now slack in the lock up would cause a shock load and that is bad. But then look at the early Colt revolvers that had no top strap and just a wedge to hold the barrel to the frame.

Although I don't think something like a 44 mag or a 500 would work out with those sized latches I think one could be made. When revolvers blow up it is almost always the cylinder that lets go and takes out the top strap. I have never seen a top strap failure where the cylinder was intact. But, I suppose it has happened.

Look at the locking lugs on bolt action rifles they work square to each other

How may have seen a top break that had the latch fail?

 

[coyotejoe]

Well I posted a photo of one in my original post and in fact most of the old break top guns if they have seen any use at all are lose, even .22's. Now admittedly I'm not talking Smith & Wesson but guns of lesser quality, still, latch failure is the number one problem with those guns.

 

[mmaher94087]

".. but guns of lesser quality, still, latch failure is the number one problem with those guns." And they are not made by Smith & Wesson.. there might be a lesson to learn in there somewhere.

 

[Bobbysixkiller]

And they are all close to, or over 100 years old.

 

[S&WsRsweet]

I must admit that once again as a new member and new collector as in I haven't actually bought a top latch yet but have my eye on one you guys are truly amazing in your knowledge of revolvers and also engineering in general .We have gone from black powder loading to heavy machinery building in this one thred .You are an amazing group of people impressive.

 

[coyotejoe]

".. but guns of lesser quality, still, latch failure is the number one problem with those guns." And they are not made by Smith & Wesson.. there might be a lesson to learn in there somewhere.

Sorry if I ruffled some feathers here, didn't mean to butcher a sacred cow. MY point was that there are better designs, not that you can't limp along with a poor design.
In Ken Waters book of pet loads he lists some .38 S&W loads with the usual warning that they are not intended for small top break guns and adds this "and in saying this I don't have reference to only the cheaper makes either, having once seen the latch blown off a fine S&W Perfected Model in almost new condition." He goes on to say the British Webley and Enfield revolvers are safe. Having owned several Webley & Enfield revolvers both large and small I certainly don't consider them to be of S&W quality but even when the soft internals are worn out they still latch up tight, their design does not demand the finest metallurgy and workmanship to compensate for a poor design.

 

[glowe]

If I remember correctly, Ken Waters was an avid wildcatter and pushed the limits of many firearms, but he apparently does not know much about S&W Models. The Perfected was a double locking revolver that locked up like a solid I frame revolver. plus had a top-latch. The last top-break design introduced by S&W and saw a total production of almost 60,000 from 1909 to 1920.

The combination of a thumb release mechanism, (where the cylinder pin that travels through the cylinder and locks into a recess in the rear frame) as seen in all solid frame S&Ws plus a top-latch makes it just about impossible for the top latch to fail without the second locking mechanism breaking as well and more likely the gun blowing apart. Any standard loading would do nothing to this gun, so who knows what the situation was that Ken referenced. Maybe someone was wildcatting the 38 S&W?? I can reference failures in just about any firearm ever manufactured, including today's models, so vague references about failures, are not scientific evidence of the inadequacies of any particular design of any brand or model revolver. If you remain very concerned about top-latch revolvers, don't buy or shoot them.

 

[mmaher94087]

No ruffled feathers here; but I do like beef. I believe Smith & Wesson recognized the limits of their top break design and that research lead to their solid frame design; larger calibers, higher pressures driving faster loads, etc.. Still, there have been catastrophic failures in that design too. Was Ken Waters in the room?

 

[BMur]

The simple truth is that the early top break design was a product of the 1870's and were designed for Black powder use only. The introduction of smokeless powder brought on a lot of significant problems for the older guns. The older top breaks also had black powder rifling. Wide lands and grooves. Pressure spikes that exceeded their design would occur with smokeless powder use. The latch and catch were not engineered to sustain this type of abuse. Hense the damage. It is true that top latch models continued into the smokeless era but they were more often backed by the engineered addition of a side latch that became the standard after the 38 perfection model was discontinued. Lets also remember that these are aged firearms that have "seen the elephant" many times. Lets cut them a little slack.

 

[glowe]

. . . The introduction of smokeless powder brought on a lot of significant problems for the older guns . . . Pressure spikes that exceeded their design would occur with smokeless powder use. The latch and catch were not engineered to sustain this type of abuse. Hense the damage . . .

The top-break S&W revolver was manufactured up to WWII and remained in S&W catalogs for almost the first half of the Twentieth Century with no mention of black powder being required. Almost all guns made the transition from black powder to smokeless without notice, by the early 1900s. There were no significant design changes made to these guns from pre-1899 days and ammunition companies still manufacture 32 S&W, 38 S&W, 44 Russian, 44-40, etc.

The 38 Perfected revolver was the only top-break to add the thumb latch and was not a popular gun, partly since it was competing with new solid frame revolvers that shot more powerful higher velocity ammunition than was available with previous models and calibers. Take a look around the Forum for many threads and posts with differing opinions, many backed by research, and experiences.

 

[coyotejoe]

My original post was intended just to discuss the variations in the latch arrangement. It seems that in 50 years of production they went through 5 different latches and , from an engineering perspective, it would appear that the earlier latches would be the stronger and more durable. It seems they never were happy with any of the latch arrangements but kept experimenting to the end.
My interest in the Safety Hammerless revolver in general was spiked by my recent acquisition of a couple of old books by Julian S. Hatcher and Elmer Keith. Both spoke favorably of the revolver for personal defense. Neither were especially thrilled with the "stopping power" of the .38 S&W cartridge, though both rated it much superior to the .380 ACP and both commented that it could be improved by hand loading with Keith's 160 grain semi-wadcutter bullet which was then (circa 1930) something new to the shooting world.
I have recently acquired a Safety Hammerless in what I believe to be the third variation and will post photos when it arrives.

 

[glowe]

I may be lucky, but I do not own any with movement and only a few with an audible clicking, but no perceptible play in the latch. I guess it is a normal metal wear issue in most cases, since some of these old top-breaks may have been opened and closed thousands of times.

 

[coyotejoe]

Question, please. In general how much play if any at all is found acceptable? I wish all of these old pistols would be rock solid when closed but most I personally saw - not many - had some little play in there when closed.

Well that is a function of the latch design. The rotary motion around the hinge pin starts out as mostly upward motion, then arching forward. That is why a latch designed to hold the top strap down against the frame, like the Webley, the Scofield and some of the other early S&Ws will remain tight while a latch designed to hold the top strap "back" against the standing breech will become lose after very little wear. It's like a chain across a door will always permit the door to open a certain amount versus a solid latch which can be fitted up quite tight and will stay tight.

 

[bmcgilvray]

Not quite on the topic at hand, but an old friend of mine used to mention that he worked summers, between college semesters, for William Crites who ran a gun shop in San Antonio, Texas in the late 1920s and early 1930s. He said that whenever top break revolvers were brought in for repair, the old man would wait until the customer exited the shop, open the revolver and rap it smartly against his work bench until the latch would lock tightly again and pronounce it "fixed."