How To Remove Firing Pin Frame Mounted S&W Revolver - Page 2

James K · May 31, 2008, 04:42 PM

It might be possible to drill out the firing pin hole from the rear on the hammer guns, but exactly how would one do that on the concealed hammer guns? Drilling from the front also keeps the bushing and firing pin hole concentric with the barrel and is just plain easier.

Threaded bushings are common on break-open shotguns, but require a special tool for removal. Plus there would be additional machine operations to thread the bushing, thread the hole, and drill the disassembly holes, with a fairly large increase in costs and with no discernable advantage. IMHO, the new S&W system is much better.

Remember, it is easy to put stuff on paper or in a CAD program, but a factory engineer has to make something that can actually be produced at a reasonable cost and can be serviced.

Jim

syamsunder · June 1, 2008, 07:14 AM

what are the factors that affect nose shape of hammer.
These are the following nose shapes for frame mounted firing pin

1* Flat face
2* flat face with a beck ( a step in vertical direction )

3 Flat face with a verical slot of width a little more than firing pin diameter.

which of them is best ?

Regarding hammer mounted firing pin --- is the diameter of firing pin is same as that of frame mounted firing pin.

syamsunder · June 1, 2008, 08:49 AM

i perfectly agree with you . what all possible on paper is not possible practically.

But what is not possible on paper / thought can nerver be possible practically leaving alone singularities of nature like in certain situations of quantum physics. ( like possible simultanious double existance and parrelel world theories )

Always i see a anology / patteren in predicting gap between thought and practice is like sequencial logical filters.

in dreems we can simply fly defying gravity. but in reality we can't. The gap between thought and external reality is because there is no absolute inner limitation ; but as we start simulating more and more external natures rules in our inner wold ;;more and more closer our imagination to external reality.

But at each stage of adding one more rule the picture changes.

like example here there is natures rules like a thin metal section behaves differently to heat treatment .That fact may not come to mind in initial design.
----------------------------------------------------------------
sir ; when C.N.C machine is at your hand then one process may be easier/ economical.
But when when you are with simple old day machines / lathes tapsets/ files ect with lot of manpower and no problem with time some other process may be cheeper.
so what i am here asking you is ( leave alone cost considerations ) if threaded houseing is having any other FUNCTIONAL PROBLEMS comapared to more advaced model of S&w ?

James K · June 1, 2008, 01:38 PM

Please do not take this wrong, but I have to say that you sound like a college sophomore. (How would I know? Been there. I sounded, I'm sure, just like you.)

FWIW, man's inability to fly like a bird is not related to any lack of imagination, but to purely physical factors, like bone mass and muscle strength.

No, there is no reason not to use a threaded bushing any of your designs would work; as I said, it is common on double shotguns. The bushing is made with two little side holes so it can be removed with a special tool. Inserting the bushing from the rear, though presents other problems, like how do you drill and tap the frame on a concealed hammer gun?

I wonder how much experience you have with CNC machines. They are not magic; any machine operation requires money spent on the machines, the tools, the power and the operator, plus the time and cost of the operation itself. Then the assembler has to screw in the bushing, another time consuming operation. All of that is a lot more costly in time and labor than simply pressing in a bushing and using a swage, all in one pass. In your second design, you introduce another production problem, with another threaded hole and screw to hold in the firing pin. More machine operations, more time, more cost, more difficulty for the gunsmith who has to replace something.

Your design thinking is OK in countries where labor and tools are cheap, and the 10 or 15 seconds to screw in a bushing won't mean much. But designers today, in a competitive environment, don't have the luxury of "cost is no object" that prevailed in older times. A designer or a production engineer of a consumer product who can save ten cents in costs or two minutes of production time is a hero.

There is absolutely nothing wrong with your design, but it is costly and has no advantage. You are falling into a common design trap - starting out to simplify something, and ending up with an even more complex system.

As to the hammer shape, the cutaway hammer face itself has no advantage; it is done for another reason, usually to allow use of a transfer bar system, which S&W does not use.

Jim

syamsunder · June 3, 2008, 09:22 AM

Thak you sir for elaborate reply.
i agree the beauty /elegance of s&w design. It is also true that the design i made is much more complex .may be with out much benefit.
--------------------------------------------------------------

I also heard a saying KISS concept ( keep it simple stupid ) where a astronaught tried to make highly complex barometric based pen for space applications ; in ink pen days. ( in space ink pen wont work )Then one of his friends suggested that using pencil is a good alternative. This is an example of KISS concept.

--------------------------------------------------------------

I am left with one doubt.
the recoil force on cartridge and primer is going to push back the firing pin is well known fact.
The area of cross section is small to resist this force by a small pin against a mini step may be 1.5 to 2 mm deep inside base of firing pin ( firing pin base dia = 4 mm nearly )
The cross pin itself is nearly 2.26 mm dia it seems to me when i have taken a tracing on over the photos you have provided.
i wonder how such small stopping surface is working.
I do not deny it is truly working .
(The older frame mounted f.p designs are with a separate recoil plate.
there the f.pin has a collar of about 7 mm dia in front of 4 mm dia zone .)

James K · June 4, 2008, 10:14 AM

The primer does indeed push back on the firing pin, but the firing pin is backed up by the hammer, which in turn is backed up by the mainspring. So the firing pin never actually moves backward in firing and the situation you envision does not occur.

Even in guns with inertia firing pins, like the M1911 pistol, the momentum of the firing pin is sufficient to prevent the primer metal from being forced into the firing pin hole (the so called "pierced primer"). Quite a few people, including some who should darn well know better, think a "pierced primer" is due to a sharp firing pin or too hard a FP blow. In fact, it is due to primer metal being forced backward into the firing pin hole, the result of a too soft firing pin strike.

Jim

syamsunder · June 5, 2008, 11:32 AM

1**can i understan that strong hammer main spring is better than week one in preventing peirceing of primers ? so that primer cup will not enter the F.Pin hole ?

2** Is the firing pin dia ( at tip ) of hammer mounted firing pin is same / nearly same as that of frame mounted firing pin ?

I know that tip dia of Frame mounted F.Pin diameter = 1.8 mm to 2 mm .

I am not aware of similar figure of hammer mounted Firing pins .

kindly clarify .
If it is also nearly 1.8 to 2 mm then it needs very narow sloat of 2 mm width need to be made in to breech plate for passage of hammer mounter F.Pin .

I am surprised hoe in olden days of hammer mounted firing pins they are able to make such narrow slot in to breech plate.

June 1, 2008, 07:14 AM	#27
syamsunder Member Join Date: October 21, 2007 Posts: 39	nose shape of hammer what are the factors that affect nose shape of hammer. These are the following nose shapes for frame mounted firing pin 1* Flat face 2* flat face with a beck ( a step in vertical direction ) 3 Flat face with a verical slot of width a little more than firing pin diameter. which of them is best ? Regarding hammer mounted firing pin --- is the diameter of firing pin is same as that of frame mounted firing pin.

June 1, 2008, 08:49 AM	#28
syamsunder Member Join Date: October 21, 2007 Posts: 39	I perfectly agree with you i perfectly agree with you . what all possible on paper is not possible practically. But what is not possible on paper / thought can nerver be possible practically leaving alone singularities of nature like in certain situations of quantum physics. ( like possible simultanious double existance and parrelel world theories ) Always i see a anology / patteren in predicting gap between thought and practice is like sequencial logical filters. in dreems we can simply fly defying gravity. but in reality we can't. The gap between thought and external reality is because there is no absolute inner limitation ; but as we start simulating more and more external natures rules in our inner wold ;;more and more closer our imagination to external reality. But at each stage of adding one more rule the picture changes. like example here there is natures rules like a thin metal section behaves differently to heat treatment .That fact may not come to mind in initial design. ---------------------------------------------------------------- sir ; when C.N.C machine is at your hand then one process may be easier/ economical. But when when you are with simple old day machines / lathes tapsets/ files ect with lot of manpower and no problem with time some other process may be cheeper. so what i am here asking you is ( leave alone cost considerations ) if threaded houseing is having any other FUNCTIONAL PROBLEMS comapared to more advaced model of S&w ?

May 31, 2008, 04:42 PM	#26
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	It might be possible to drill out the firing pin hole from the rear on the hammer guns, but exactly how would one do that on the concealed hammer guns? Drilling from the front also keeps the bushing and firing pin hole concentric with the barrel and is just plain easier. Threaded bushings are common on break-open shotguns, but require a special tool for removal. Plus there would be additional machine operations to thread the bushing, thread the hole, and drill the disassembly holes, with a fairly large increase in costs and with no discernable advantage. IMHO, the new S&W system is much better. Remember, it is easy to put stuff on paper or in a CAD program, but a factory engineer has to make something that can actually be produced at a reasonable cost and can be serviced. Jim

June 1, 2008, 01:38 PM	#29
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	Please do not take this wrong, but I have to say that you sound like a college sophomore. (How would I know? Been there. I sounded, I'm sure, just like you.) FWIW, man's inability to fly like a bird is not related to any lack of imagination, but to purely physical factors, like bone mass and muscle strength. No, there is no reason not to use a threaded bushing any of your designs would work; as I said, it is common on double shotguns. The bushing is made with two little side holes so it can be removed with a special tool. Inserting the bushing from the rear, though presents other problems, like how do you drill and tap the frame on a concealed hammer gun? I wonder how much experience you have with CNC machines. They are not magic; any machine operation requires money spent on the machines, the tools, the power and the operator, plus the time and cost of the operation itself. Then the assembler has to screw in the bushing, another time consuming operation. All of that is a lot more costly in time and labor than simply pressing in a bushing and using a swage, all in one pass. In your second design, you introduce another production problem, with another threaded hole and screw to hold in the firing pin. More machine operations, more time, more cost, more difficulty for the gunsmith who has to replace something. Your design thinking is OK in countries where labor and tools are cheap, and the 10 or 15 seconds to screw in a bushing won't mean much. But designers today, in a competitive environment, don't have the luxury of "cost is no object" that prevailed in older times. A designer or a production engineer of a consumer product who can save ten cents in costs or two minutes of production time is a hero. There is absolutely nothing wrong with your design, but it is costly and has no advantage. You are falling into a common design trap - starting out to simplify something, and ending up with an even more complex system. As to the hammer shape, the cutaway hammer face itself has no advantage; it is done for another reason, usually to allow use of a transfer bar system, which S&W does not use. Jim

June 3, 2008, 09:22 AM	#30
syamsunder Member Join Date: October 21, 2007 Posts: 39	Thak you sir for elaborate reply. i agree the beauty /elegance of s&w design. It is also true that the design i made is much more complex .may be with out much benefit. -------------------------------------------------------------- I also heard a saying KISS concept ( keep it simple stupid ) where a astronaught tried to make highly complex barometric based pen for space applications ; in ink pen days. ( in space ink pen wont work )Then one of his friends suggested that using pencil is a good alternative. This is an example of KISS concept. -------------------------------------------------------------- I am left with one doubt. the recoil force on cartridge and primer is going to push back the firing pin is well known fact. The area of cross section is small to resist this force by a small pin against a mini step may be 1.5 to 2 mm deep inside base of firing pin ( firing pin base dia = 4 mm nearly ) The cross pin itself is nearly 2.26 mm dia it seems to me when i have taken a tracing on over the photos you have provided. i wonder how such small stopping surface is working. I do not deny it is truly working . (The older frame mounted f.p designs are with a separate recoil plate. there the f.pin has a collar of about 7 mm dia in front of 4 mm dia zone .)

June 4, 2008, 10:14 AM	#31
James K Member In Memoriam Join Date: March 17, 1999 Posts: 24,383	The primer does indeed push back on the firing pin, but the firing pin is backed up by the hammer, which in turn is backed up by the mainspring. So the firing pin never actually moves backward in firing and the situation you envision does not occur. Even in guns with inertia firing pins, like the M1911 pistol, the momentum of the firing pin is sufficient to prevent the primer metal from being forced into the firing pin hole (the so called "pierced primer"). Quite a few people, including some who should darn well know better, think a "pierced primer" is due to a sharp firing pin or too hard a FP blow. In fact, it is due to primer metal being forced backward into the firing pin hole, the result of a too soft firing pin strike. Jim

June 5, 2008, 11:32 AM	#32
syamsunder Member Join Date: October 21, 2007 Posts: 39	1can i understan that strong hammer main spring is better than week one in preventing peirceing of primers ? so that primer cup will not enter the F.Pin hole ? 2 Is the firing pin dia ( at tip ) of hammer mounted firing pin is same / nearly same as that of frame mounted firing pin ? I know that tip dia of Frame mounted F.Pin diameter = 1.8 mm to 2 mm . I am not aware of similar figure of hammer mounted Firing pins . kindly clarify . If it is also nearly 1.8 to 2 mm then it needs very narow sloat of 2 mm width need to be made in to breech plate for passage of hammer mounter F.Pin . I am surprised hoe in olden days of hammer mounted firing pins they are able to make such narrow slot in to breech plate.