3904 safety is blackened stainless
- Thread starter rosewood
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When S&W changed over to using MIM for many of the smaller assemblies, they used stainless MIM and applied a black finish to it (not blued).
BTW, if you don't mind me asking, when you disassembled your manual safety assemblies, did you make sure the different plungers and springs didn't get mixed up during reassembly?
The reason I ask is that if the springs for the body plunger and the ambi lever plunger get switched, the lever spring won't be strong enough to prevent the mass of the manual safety assembly from moving under recoil and cycling. This typically means a pistol with switched springs can start 'decocking itself' and remaining On-Safe when fired.
Of course, a hint will be that trying to stuff the body plunger spring under the ambi lever is really difficult, because the spring is a lot heavier than the light ambi lever spring.
If the plungers are mixed up, the lever might not remain firmly captured by the plunger, and the decocking may feel very rough. The heads of the body plunger and ambi lever plunger are different. The body plunger must be the round-headed plunger. There was a transitional plunger in the older 3rd gen guns that could be mistaken for the body plunger if an armorer wasn't paying attention.
In this pic the Body plunger (fully rounded head) is on the bottom, and the ambi lever plunger is the middle one. The top one was originally the .45 ambi lever plunger, and eventually became the standard ambi lever plunger for 9/.40 guns, too. (The size of the plunger head requires a different lever, to fit the wide head.)
You can see how a quick glance might mistake the ambi lever plunger for the older body plunger.
When new, the lever spring would be painted light blue, and the body plunger is unpainted. Another clue is that the ambi lever spring is light enough in tension that it can be easily compressed between thumb and finger, but the body plunger spring will want to punch holes in your skin.
Sorry to post such trivia that may already be known to you, but I've seen some lesser experienced armorers make the mistake of switching either the springs, or the plungers, or both springs & plungers, at the bench without realizing it.
A friend of mine at another agency (head armorer) had one of his newly minted armorers mistakenly do that to a number of their 4006's once, during an inspection. It wasn't noticed until the next qualification quarter ... when those 4006's started decocking themselves with each shot and remaining in the On-Safe/decocked position.
Lucky there hadn't been any shooting incidents in the meantime, huh? 
BTW, if you don't mind me asking, when you disassembled your manual safety assemblies, did you make sure the different plungers and springs didn't get mixed up during reassembly?
The reason I ask is that if the springs for the body plunger and the ambi lever plunger get switched, the lever spring won't be strong enough to prevent the mass of the manual safety assembly from moving under recoil and cycling. This typically means a pistol with switched springs can start 'decocking itself' and remaining On-Safe when fired.
Of course, a hint will be that trying to stuff the body plunger spring under the ambi lever is really difficult, because the spring is a lot heavier than the light ambi lever spring.
If the plungers are mixed up, the lever might not remain firmly captured by the plunger, and the decocking may feel very rough. The heads of the body plunger and ambi lever plunger are different. The body plunger must be the round-headed plunger. There was a transitional plunger in the older 3rd gen guns that could be mistaken for the body plunger if an armorer wasn't paying attention.
In this pic the Body plunger (fully rounded head) is on the bottom, and the ambi lever plunger is the middle one. The top one was originally the .45 ambi lever plunger, and eventually became the standard ambi lever plunger for 9/.40 guns, too. (The size of the plunger head requires a different lever, to fit the wide head.)
You can see how a quick glance might mistake the ambi lever plunger for the older body plunger.
When new, the lever spring would be painted light blue, and the body plunger is unpainted. Another clue is that the ambi lever spring is light enough in tension that it can be easily compressed between thumb and finger, but the body plunger spring will want to punch holes in your skin.
Sorry to post such trivia that may already be known to you, but I've seen some lesser experienced armorers make the mistake of switching either the springs, or the plungers, or both springs & plungers, at the bench without realizing it.
A friend of mine at another agency (head armorer) had one of his newly minted armorers mistakenly do that to a number of their 4006's once, during an inspection. It wasn't noticed until the next qualification quarter ... when those 4006's started decocking themselves with each shot and remaining in the On-Safe/decocked position.
Lucky there hadn't been any shooting incidents in the meantime, huh? Yep I found the difference. Safety spring is stronger than the lever spring, and it is obvious to me which plunger goes where. I have dis and reassembled many 3rd gens in the last couple of years.
Thanks for the reminder though.
Rosewood
Thanks for the reminder though.
Rosewood
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When S&W changed over to using MIM for many of the smaller assemblies, they used stainless MIM and applied a black finish to it (not blued).
BTW, if you don't mind me asking, when you disassembled your manual safety assemblies, did you make sure the different plungers and springs didn't get mixed up during reassembly?
The reason I ask is that if the springs for the body plunger and the ambi lever plunger get switched, the lever spring won't be strong enough to prevent the mass of the manual safety assembly from moving under recoil and cycling. This typically means a pistol with switched springs can start 'decocking itself' and remaining On-Safe when fired.
Of course, a hint will be that trying to stuff the body plunger spring under the ambi lever is really difficult, because the spring is a lot heavier than the light ambi lever spring.
If the plungers are mixed up, the lever might not remain firmly captured by the plunger, and the decocking may feel very rough. The heads of the body plunger and ambi lever plunger are different. The body plunger must be the round-headed plunger. There was a transitional plunger in the older 3rd gen guns that could be mistaken for the body plunger if an armorer wasn't paying attention.
In this pic the Body plunger (fully rounded head) is on the bottom, and the ambi lever plunger is the middle one. The top one was originally the .45 ambi lever plunger, and eventually became the standard ambi lever plunger for 9/.40 guns, too. (The size of the plunger head requires a different lever, to fit the wide head.)
You can see how a quick glance might mistake the ambi lever plunger for the older body plunger.
When new, the lever spring would be painted light blue, and the body plunger is unpainted. Another clue is that the ambi lever spring is light enough in tension that it can be easily compressed between thumb and finger, but the body plunger spring will want to punch holes in your skin.
Sorry to post such trivia that may already be known to you, but I've seen some lesser experienced armorers make the mistake of switching either the springs, or the plungers, or both springs & plungers, at the bench without realizing it.
A friend of mine at another agency (head armorer) had one of his newly minted armorers mistakenly do that to a number of their 4006's once, during an inspection. It wasn't noticed until the next qualification quarter ... when those 4006's started decocking themselves with each shot and remaining in the On-Safe/decocked position.
I have a mechanical mind and quite adept at seeing how things fit together. The 1st smith revolver I worked on came to me in pieces and I figured out how it went together.
De nada. No biggie. It's just that it's an easy thing for even armorers to mix up without realizing it, especially if they don't inspect or service 3rd gens very often.
Annoying when a gun starts decocking 'automatically' on the range, and more than annoying if it were to happen outside the range environment, like when you really needed it work normally.
This is something that anyone taking them apart should know, before.
I thank you again Fastbolt for perfectly explaining, (with great images,) the difference.
Somewhat recently I got a kinda special PC example from a member here. It came with an incorrect ambi. Disassembly of the top end was a task. Incorrect ambi lever spring AND incorrect lever. Push down plunger/spring, tap tap tap lever, repeatedly. I don't understand the different numbers on the levers but someone, (NOT the seller,) forced an incorrect lever on top of an incorrect spring.
Jim
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Yep, it can happen.
The numbers on the back sides of the levers are, according to what we were told, not part/model numbers.
The machined recess that captures the head of the plunger came in 2 sizes, for the different sized/shaped plunger heads. The older 'shouldered' plunger had a smaller head, while the larger plunger had no shoulder, being straight-walled to the top (although there is a slight beveled edge at the top).
In these hasty pics (just made at my bench) you can see the differences in the recess on the back of the levers, and the way the appropriate plungers fit in them.
There is another ambi lever, for the .45's, that has a spacer pad on the back.
After the spring-loaded, decock-only option had been out as a LE option on the 9/.40 guns for a couple years, it was determined that the .45 ambi lever pad needed to be used with the decock-only option on the 9/.40 guns. We were told the reason was that the regular 9/.40 ambi levers might allow for excessive lateral shifting of the decocking body inside the slide, which might interfere with freedom of movement of the firing pin (impact force).
It was a little confusing when this was first mentioned in an armorer class update, and a revision added to the manual discussing the need for the .45 ambi lever in 9/.40 guns in which the decock-only body was installed. The first time I called the LE Customer Service guy to order a .45 ambi lever for my 3913 (which had the decock-only feature), the guy on the phone had not yet heard of the need for the .45 lever in 9's equipped with the decock-only body. Just went to show that the folks in Training, Repair, Engineering, Parts and the PC (doing the decock-only work at that time) might not all be sharing information?
Anyway, when the .45 lever arrived and I installed it in my 3913, I checked and noticed that there was a difference in possible lateral movement and play of the decocking body with the different levers installed. The original 9/.40 lever allowed for a little bit of side-to-side wiggle if I pushed against the sides of the assembly, and the .45 lever didn't.
This pic shows the extra material on the back of the .45 lever (pin punch pointing to it) that indexes against the outside of the slide under the lever.
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Found out last night the slide stop on the 3904 is blued steel, but the 915 has a blackened stainless one. I did blast the 3904 stop and it took blueing fine. Glad I didn't blast the 915 slide stop, I tried touching up the blueing and it won't take.
Rosewood
Rosewood
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