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how do i adjust tthe spring tension
- Thread starter ian45662
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On post here, they say 3lbs for frizzen spring and 10 for main. Zonie and Paul know. I did one of each, you are to file long ways on springs. I am not sure how is right way for sure. I lighten them up by filing them the length or long ways on them. It help them anyway. These were CVA locks. Will watch and see what they tellyou. Dilly
Many Klatch
69 Cal.
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You make a V-Spring stronger by wedging a V shaped piece of wood into the elbo of the spring. Making one weaker is a little trickier, it involves grinding little bits off until it is just right.
Good luck.
Many Klatch
Good luck.
Many Klatch
I moved this post to the Gun Builders Bench because that's where questions dealing with working on your gun fits best.
I hope all of those folks who are interested in this will follow the link. :grin:
My answer follows:
Well, the thing you don't want to do is to try to over-bend them. You also don't want to heat them much above 500 degrees F and this is not enough to soften them to allow bending so don't try it.
Boar-dilly got it right about filing the long way on these springs.
Filing or grinding across the spring perpendicular to the flat surfaces will produce small vertical scratches along the edge. These scratches will have very high stresses right at the bottom of each one and these stresses will cause the spring to break over time (and sometimes that length of time is just a few seconds after the spring is put under tension.) :shocked2:
With that out of the way, I should point out that decreasing the width will reduce the springs pressure on a one to one basis.
Put another way, if you reduced the width by one half (50%) the end product would have a force one half as much as the original.
If you reduced the width 10% the result will be a spring that has 90% of the force of the original.
If you reduce the thickness , it will reduce the force by the cube of the thickness of reduction. That is to say, if the reworked spring thickness is reduced 1/3, the resulting spring will have a force of 1/27th of the original (3 cubed is 27). These numbers aren't exactly right, but you get the idea.
The stresses within the spring increase equally fast which can cause a failure.
Carefully done, this is a fast way to reduce the pressure but it is very easy to go too far
so I cannot recommend this.
As was mentioned above, grind or file marks perpendicular to the surface will cause problems and the bend of the V or U spring is dam hard to file or grind around without producing them.
To help this troublesome area, I would recommend using silicone carbide (black) wet/dry sandpaper to remove all traces of any marks produced by reducing the springs width.
Start with 150 grit and work down to 600 grit. The more polished it is, the better providing all traces of marks are removed. Leaving just one can cause problems.
File or grinding marks that are running parallel with the springs blade won't cause too much of a problem, but it is a good idea to remove these as well if you want a spring that will last.
Have fun.
zonie
I hope all of those folks who are interested in this will follow the link. :grin:
My answer follows:
Well, the thing you don't want to do is to try to over-bend them. You also don't want to heat them much above 500 degrees F and this is not enough to soften them to allow bending so don't try it.
Boar-dilly got it right about filing the long way on these springs.
Filing or grinding across the spring perpendicular to the flat surfaces will produce small vertical scratches along the edge. These scratches will have very high stresses right at the bottom of each one and these stresses will cause the spring to break over time (and sometimes that length of time is just a few seconds after the spring is put under tension.) :shocked2:
With that out of the way, I should point out that decreasing the width will reduce the springs pressure on a one to one basis.
Put another way, if you reduced the width by one half (50%) the end product would have a force one half as much as the original.
If you reduced the width 10% the result will be a spring that has 90% of the force of the original.
If you reduce the thickness , it will reduce the force by the cube of the thickness of reduction. That is to say, if the reworked spring thickness is reduced 1/3, the resulting spring will have a force of 1/27th of the original (3 cubed is 27). These numbers aren't exactly right, but you get the idea.
The stresses within the spring increase equally fast which can cause a failure.
Carefully done, this is a fast way to reduce the pressure but it is very easy to go too far
so I cannot recommend this.
As was mentioned above, grind or file marks perpendicular to the surface will cause problems and the bend of the V or U spring is dam hard to file or grind around without producing them.
To help this troublesome area, I would recommend using silicone carbide (black) wet/dry sandpaper to remove all traces of any marks produced by reducing the springs width.
Start with 150 grit and work down to 600 grit. The more polished it is, the better providing all traces of marks are removed. Leaving just one can cause problems.
File or grinding marks that are running parallel with the springs blade won't cause too much of a problem, but it is a good idea to remove these as well if you want a spring that will last.
Have fun.
zonie
Simply reducing the weight of the springs may or may not solve your problem.
For example, bashing flints is more often the result of a "grabby", or too soft frizzen or an overly weak frizzen spring rather than springs that are too strong.
It would help if you explained the problem with your lock, and the make of the lock. Some makes have specific problems due to design or production flaws.
J.D.
For example, bashing flints is more often the result of a "grabby", or too soft frizzen or an overly weak frizzen spring rather than springs that are too strong.
It would help if you explained the problem with your lock, and the make of the lock. Some makes have specific problems due to design or production flaws.
J.D.
paulvallandigham
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Board Dilly has it right about filing flat springs. If you look at original forges springs, including those made by Herschel House, and his brother, they start with a stright piece of spring steel stock, then heat it to bend it into a " V " shape, adjusting the length of the arms of the " V ", and putting the hook or claw, or whatever is needed to mount the spring to the lock plate, and moving parts.
When you look at modern springs, they are cast, and they have HUGE amounts of material at the base of the " V ". Grind and file that material down first. I found that doing so helps to release the amount of tension in the moving arm faster, than filing the arm itself. You also can file the SIDES of the leaves or arms, concentrating on the arm that moves, rather than the arm that is fixed. On the frizzen spring, the working arm is on the upside: On the mainspring, the moving arm in on the bottom side of the < .
How much ? This is always a matter of trial and error as each spring is going to be different.
With the Frizzen Spring, I find that I FIRST should file and smooth down the ares of the spring where contact is made between the heel of the frizzen, and the spring. Polish the heck out of the spring, and file or remove any casting burrs that exist on the heel. ( If you remove the frizzen from the bridle, and put it on a shelf to look at it sideways, It looks like a funny shaped boot with a high " heel ".) DO NOT FILE DOWN THAT HEEL! Polish it. Some need to have the curve on the heel re-shaped, so that the heel does not compress the arm when the frizzen open, but this is due to the lock maker having the spring arm continue to climb up above the point where the heel contacts the arm when the frizzen is closed. The frizzen spring should not be used to keep the frizzen from opening after contact is made by the edge of the flint with the frizzen. This kind of spring design was used to " fudge " some bad lock geometry, so that the lock would spark, even if the cock is located too far back, or too far forward from the frizzen. The result of combining bad geometry, and poor spring design is flints being eaten, and frizzens looking like washboards with only a few hundred firings.
Some locksmiths will heat up the frizzen spring, and turn that end down to it is parallel to the bottom edge of the lockplate from the point where the heel contacts the spring, to the end, and some just grind off the end, as it performs no real function . I like to leave the end on, and file the hell out of the part of the spring arm, to allow the frizzen to open without the heel compressing the spring further. The heel should look like a " Cuban Heel " boot in reverse, that is, the rounded edge of the heel should be towards the toe of the frizzen, and not to the back. The back edge is where you want full contact, with the spring, to keep the frizzen closed. You can leave a small flat on it, like 1/64" wide, to help it stand up on the spring arm when the frizzen is closed. Use a trigger pull gauge, hooked over the top fo the frizzen, and pulled forward until the frizzen snaps open, to determine the spring tension. 3 lbs is more than enough to keep the frizzen closed, regardless of what attitude the gun is carried. ( That means you should be able to carry the gun upside down, and even shake it without the frizzen popping open., or bang the muzzle of the gun on something ((soft!)) without the frizzen popping open. ) The total weight of most frizzens is less than 1 lbs, so having a spring with more than 3 times the tension should give enough insurance that the frizzen will not pop open.
The mainspring tension can vary from gun to gun. On a good lock with good geometry, a 10 lbs mainspring is more than enough to spark the lock. I now tell people to use 15 lbs as their objective, and only after shooting the gun for awhile, at the higher tension rate, and checking it to see that the spring is not " weakening "( It shouldn't) then slowly take it down to 10 lbs. Since I can't control how you do this work, I think its better that you have a good margin for error. I have done this more than once, so I don't need that margin as badly as I once did.
If I can, I leave filing down the thickness of the spring arms to the last resort. I have found casting flaws and voids appear doing this that has required me to get a replacement spring on more than one occasion. I stick to filing the side of the moving arm to reduce the tension after thinning the bottom of the " V ". The one caution I make to others is to draw a line from the tip of the spring arm to a point about 1/2 ahead of the bottom of the "V" and then file a long bevel to the side of the arm. You want the entire arm to move and work as a unit, and not just the tip of the arm. When you get back near the bottom of the "V", you will find almost no movement, mostly because the spring is made so wide, and those arms are very thick from the casting process back there.
If you do choose to file the flat of the spring arm, start at the bottom of the "V" and try to thin that material of the arm first. Again, remember Boar Dilly's advice, and file lengthwise, and not across the arm.
When you look at modern springs, they are cast, and they have HUGE amounts of material at the base of the " V ". Grind and file that material down first. I found that doing so helps to release the amount of tension in the moving arm faster, than filing the arm itself. You also can file the SIDES of the leaves or arms, concentrating on the arm that moves, rather than the arm that is fixed. On the frizzen spring, the working arm is on the upside: On the mainspring, the moving arm in on the bottom side of the < .
How much ? This is always a matter of trial and error as each spring is going to be different.
With the Frizzen Spring, I find that I FIRST should file and smooth down the ares of the spring where contact is made between the heel of the frizzen, and the spring. Polish the heck out of the spring, and file or remove any casting burrs that exist on the heel. ( If you remove the frizzen from the bridle, and put it on a shelf to look at it sideways, It looks like a funny shaped boot with a high " heel ".) DO NOT FILE DOWN THAT HEEL! Polish it. Some need to have the curve on the heel re-shaped, so that the heel does not compress the arm when the frizzen open, but this is due to the lock maker having the spring arm continue to climb up above the point where the heel contacts the arm when the frizzen is closed. The frizzen spring should not be used to keep the frizzen from opening after contact is made by the edge of the flint with the frizzen. This kind of spring design was used to " fudge " some bad lock geometry, so that the lock would spark, even if the cock is located too far back, or too far forward from the frizzen. The result of combining bad geometry, and poor spring design is flints being eaten, and frizzens looking like washboards with only a few hundred firings.
Some locksmiths will heat up the frizzen spring, and turn that end down to it is parallel to the bottom edge of the lockplate from the point where the heel contacts the spring, to the end, and some just grind off the end, as it performs no real function . I like to leave the end on, and file the hell out of the part of the spring arm, to allow the frizzen to open without the heel compressing the spring further. The heel should look like a " Cuban Heel " boot in reverse, that is, the rounded edge of the heel should be towards the toe of the frizzen, and not to the back. The back edge is where you want full contact, with the spring, to keep the frizzen closed. You can leave a small flat on it, like 1/64" wide, to help it stand up on the spring arm when the frizzen is closed. Use a trigger pull gauge, hooked over the top fo the frizzen, and pulled forward until the frizzen snaps open, to determine the spring tension. 3 lbs is more than enough to keep the frizzen closed, regardless of what attitude the gun is carried. ( That means you should be able to carry the gun upside down, and even shake it without the frizzen popping open., or bang the muzzle of the gun on something ((soft!)) without the frizzen popping open. ) The total weight of most frizzens is less than 1 lbs, so having a spring with more than 3 times the tension should give enough insurance that the frizzen will not pop open.
The mainspring tension can vary from gun to gun. On a good lock with good geometry, a 10 lbs mainspring is more than enough to spark the lock. I now tell people to use 15 lbs as their objective, and only after shooting the gun for awhile, at the higher tension rate, and checking it to see that the spring is not " weakening "( It shouldn't) then slowly take it down to 10 lbs. Since I can't control how you do this work, I think its better that you have a good margin for error. I have done this more than once, so I don't need that margin as badly as I once did.
If I can, I leave filing down the thickness of the spring arms to the last resort. I have found casting flaws and voids appear doing this that has required me to get a replacement spring on more than one occasion. I stick to filing the side of the moving arm to reduce the tension after thinning the bottom of the " V ". The one caution I make to others is to draw a line from the tip of the spring arm to a point about 1/2 ahead of the bottom of the "V" and then file a long bevel to the side of the arm. You want the entire arm to move and work as a unit, and not just the tip of the arm. When you get back near the bottom of the "V", you will find almost no movement, mostly because the spring is made so wide, and those arms are very thick from the casting process back there.
If you do choose to file the flat of the spring arm, start at the bottom of the "V" and try to thin that material of the arm first. Again, remember Boar Dilly's advice, and file lengthwise, and not across the arm.
