Pedersoli AN IX: Killing My Flint (*PICTURES*)

[ebiggs1]

No I am not following you. I am kinda dense sometimes and it take a bit to get the jest of something. I know when I started work as a tool and die maker we had to change springs on machinery after several 1000 cycles. When I retired some 40 years later similar machinery never needs its springs replaced. There had to be some advance in spring technology in that time period. But like Coyote Joe tried to point out, I don’t have to jump off a cliff to know what the result will be. That is why I believed the modern spring could be made stronger. Do you think Pedersoli uses the same steel, as did 1700’s gun makers?
I don’t know but I doubt it?

 

[Zonie]

I don't want to get too far from the original post but I'll stick to my guns when it comes to spring deflection and forces and Old steel and new steel.

As for replacing springs, if the original was not properly heat treated or it was the wrong type of steel without sufficient yield strength the springs would be overstressed and not return to their original shape. It may take several thousand cycles for this to happen.

The replacement springs either were heat treated to a higher yield strength or they may have been slightly larger in cross section (at the cost of a higher spring rate). A few thousandths of an inch in thickness makes a tremendous difference because deflection loads (and conversely stress levels) works as the Cube of the thickness.

Getting back to the feather spring, because the spring rate works as the cube of the thickness that is the reason I say NEVER reduce the thickness of a leaf spring to adjust the spring pressure (or rate). It is just too easy to remove too much material and greatly reduce the spring rate and raise the operating stress. (If the operating stress gets too high the spring will either exceed its yield strength and fail to return to its original position or it will break.

When adjusting flat spring pressures always decrease the width filing or sanding in the direction of the leaf, never across it.
The spring rate works directly in relation to the width. In other words, if it is 1/2 as wide as it was it will have 1/2 the power.
This is much easier to work with and control than messing with the thickness.

 

[CoyoteJoe]

Thanks for that explaination Zonie. I've always found it much easier to reduce the width in a uniform manner than to get a uniform taper grind on the concave surface of a spring. It's good to know I was doing the right thing even though it was for the wrong reason, ie: laziness. :haha:
I've made quite a few springs using annealed spring stock from Dixie Gun Works and tempering them in my lead pot. They work great and it's sometimes easier to make a new spring than to rework an old one.

 

[ozark57]

I don't want to get too far from the original post but I'll stick to my guns when it comes to spring deflection and forces and Old steel and new steel.

As for replacing springs, if the original was not properly heat treated or it was the wrong type of steel without sufficient yield strength the springs would be overstressed and not return to their original shape. It may take several thousand cycles for this to happen.

The replacement springs either were heat treated to a higher yield strength or they may have been slightly larger in cross section (at the cost of a higher spring rate). A few thousandths of an inch in thickness makes a tremendous difference because deflection loads (and conversely stress levels) works as the Cube of the thickness.

Getting back to the feather spring, because the spring rate works as the cube of the thickness that is the reason I say NEVER reduce the thickness of a leaf spring to adjust the spring pressure (or rate). It is just too easy to remove too much material and greatly reduce the spring rate and raise the operating stress. (If the operating stress gets too high the spring will either exceed its yield strength and fail to return to its original position or it will break.

When adjusting flat spring pressures always decrease the width filing or sanding in the direction of the leaf, never across it.
The spring rate works directly in relation to the width. In other words, if it is 1/2 as wide as it was it will have 1/2 the power.
This is much easier to work with and control than messing with the thickness.

Zonie, I am no saying I disagree , but the mechanical properties of steel are affected by many variables, such as carbon content, heat treat and anealing. Also, most modern springs are alloys containing at least some nickel and chromium. Not trying to be argumentive, just trying to understand.

 

[ebiggs1]

Zonie you obliviously know about springs than I but the question still remains, does Pedersoli use the same steel as the 1700 gun makers did? And does the lighter spring rate work better, which I say it does?

 

[boar]

I will second that. Only flint that will last in mine ia a man made one. :thumbsup: Dilly

 

[paulvallandigham]

The only thing I would add to your comments on springs is that rounding the edges of a leaf spring makes the springs more flexible, and reduces the chance of the leaf breaking. :thumbsup:

Removing burrs from the edges of any leaf spring is always the first place to start, when tuning springs, in locks. Simply reducing the friction caused by burrs rubbing against the lockplate will make a significant difference in the performance of the leaf spring.

 

[Va.Manuf.06]

No I am not following you. I am kinda dense sometimes and it take a bit to get the jest of something. I know when I started work as a tool and die maker we had to change springs on machinery after several 1000 cycles. When I retired some 40 years later similar machinery never needs its springs replaced. There had to be some advance in spring technology in that time period. But like Coyote Joe tried to point out, I don’t have to jump off a cliff to know what the result will be. That is why I believed the modern spring could be made stronger. Do you think Pedersoli uses the same steel, as did 1700’s gun makers?
I don’t know but I doubt it?

It is not the quality of the springs that changed, it was the quality of the accounting. 99.99% of those springs did not need changing, not then and not ever, they would have lasted for ever. The reason for spring replacement was the very small possibility that one would fail and that would have caused an expensive shut down at a likely costly time. As time went on and the failure rate of the springs was noted to be very small, the bean counters were able to convince the boss to reduce the change over schedule. Get back to the subject, Zonie knows what he is talking about.

 

[Steve Boyleston]

Burke buy flint on Ebay much cheaoer Great Flint. TGP

 

[Zonie]

I have no idea about the exact kind of steel that Pedersoli uses to make their springs.
As the Europeans use different nomenclature for their steels even if they told me what it was it would take some research to try to figure out what U.S. steel would be comparable.

As for the steels used back in the 18th and 19th century I have even less information.
I'm sure they contained some impurities that modern steels don't have.
Our steel companies know the exact percentages of what exists in the steels they make to the one thousandth percent and have ways of measuring these things. The old timers could only dream of having such information and likely wouldn't know the significance if they had it.

They did have the knowledge of what basic type of steel made a good spring or a bad spring.
I doubt that they understood exactly why tempering worked but they knew how important it was and they knew how to achieve it.

By the way, in another post I mention the cam on the frizzen and the need to eliminate any burr, mis-match or sudden projections on it.

The shape of this cam can have a lot to do with a poorly functioning frizzen.

The bottom line about flint life is that all flints are not created equal.
When one starts to dull it needs to be re-knapped.
Some locks have cocks that present the flint at the wrong angle to the frizzen and no amount of messing with the springs will fix that.

If the shooter thinks the flint is hitting the frizzen to squarely (rather than at the 'slicing angle' it should) they can try putting a small wedge under the flint to try to improve things but in the long run if the distance between the tumbler and the face of the frizzen is wrong there is little they can do except enjoy the few shots their flint will give them (and swear profusely under their breath).

 

[CoyoteJoe]

Zonie sayath "If the shooter thinks the flint is hitting the frizzen to squarely (rather than at the 'slicing angle' it should) they can try putting a small wedge under the flint to try to improve things but in the long run if the distance between the tumbler and the face of the frizzen is wrong there is little they can do except enjoy the few shots their flint will give them (and swear profusely under their breath). Quoth Zonie

I say "AMEN"!!

 

[cmdrted]

Just a small contribution. I bought a pedersoli kentucky flint pistol kit last summer from dixie. The lock had springs from hell. The frizzen spring was thick wide and took greater than 15+ lbs to open. Luckily the truck suspension spring, er mainspring, was also as thick and wide. I feared for my fingers every time I tried to cock the thing. My bottom line is they are somewhat stronger than they have to be. This may be why your flints are short lived.

 

[cutshurt]

You could try fliping your flint and try it with the bevel down...see if that helps.

Darrel

 

[brubincam]

-----IT's SPRING TIME-----