Questions about the historical use of coil springs

[44-henry]

I picked up an old Navy Arms underhammer lock the other day and was studying the workings of it. I notice that the Navy Arms version uses a coil spring under the sear, yet they are still using a flat mainspring. I really don't care for coil springs, but I was curious how many (if it was even done) mid 1800's percussion locks of this type did actually use coil springs.

[smart dog]

Hi Alex,
You ask a very good question and I can only speculate at an answer about their lack of use.  First, coil springs were around almost as long as guns. They were used in door locks in the 16th (and possibly 15th) century.  Leonardo DaVinci drew coil springs in at least one of his sketch books. He even shows a tinder lighter powered by a coil spring.  I would not be surprised if coil springs were found in a few of the early experiemnts with breechloading and repeating guns for locking gas seals in place or pushing bullets into place for loading. Coils were frequently used of course in watches and clocks. I think the problem for early gunmakers might be that the poor quality of steel during those centuries made forging coil springs sufficiently large for mainsprings in guns difficult. The springs might have been hard to temper properly and possibly they would sag quickly. Vee-shaped springs offered an advantage in that you could make them thick and heavy but with a relatively soft temper which gave a large margin for error due to poor material. Coil springs were fine for small spaces and light duty as in watches and locks but impractical for mainsprings on guns.  Of course there is also the possibility that gunsmiths understood that coils springs absolutely suck as mainsprings because of the physics of their action.  They cannot compare with v springs in gun locks for feel and mechanical advantage. Anyway Alex, I am speculating on all this so take it for what it is worth.

dave   

[smart dog]

Hi Alex,
I realize after reading your question again that you were not asking about coils and their general use in gun locks but just for underhammers of the type you had. For a light duty spring for the sear, I would not be surprised if coils were used and your reproduction is historically accurate, although I have never inspected an original underhammer lock. My original 1862 Sharps carbine has a small coil spring that puts pressure on the detent that locks the lever that holds the action in place. So coils were certainly used in production guns during the mid-19th century. But like I mentioned previously, it also doesn't surprise me that they would not use a coil spring for the mainspring even if they did use one for the sear spring.

dave 

[44-henry]

Dave,
Thanks for your response. I meant to say mule ear as that is the lock I was looking at, I must have been thinking of something else when I typed underhammer. In any event, you answered my question. Thanks again.

Alex Johnson

[Dphariss]

Generally speaking coil springs make crappy lock springs.
Not enough power in most cases and "slow" compared to a good leaf spring.
Quality side locks never use them.
Dan

[Dphariss]

I missed one point.They can be made by the thousands on automatic machinery.
A good leave spring cannot.

Dan