Bad sparking is the result of poor designed locks, frizzen springs that keep the frizzen from opening quickly, mainsprings that are too hard, and smash the flints, and poor loading and maintenance procedures.
The flint most strike the face of the frizzen at a 60 degree angle, if you are going to get good sparks, AND have the natural fracture lines of the silica molecules help break off a very tiny portion of the edge, to give you a new, sharp, clean edge for the next shot. How you get that 60 degree angle is not as important as getting it.
Use a protractor, with the baseline along the bottom of the flint/top of the bottom jaw of the cock, and the centerpoint of the protractor located at the point of impact( POI) of the edge of your flint to the frizzen.
You want the flint to strike the frizzen between 60% and 66% of the height UP from the bottom of the frizzen, as it is closed over the pan. You want a flint in the cock short enough to NOT touch the frizzen when the hammer is at half-cock, and you also want it to NOT strike the bottom of the flashpan when fully lowered. Also, check to make sure the flint as set into the jaws, will NOT scrape or strike the side of the barrel during the fall.
There are 3 springs to any flintlock, and Two of them affect how much tension there is on the frizzen and your flint. That determines how much of the flint is destroyed when the hammer falls, and how many strikes you get. The ONLY JOB OF THAT FRIZZEN SPRING IS TO KEEP THE FRIZZEN CLOSED WITH THE BARREL IS POINTED TO THE GROUND. It is Not intended to put resistence on the flint to keep the frizzen from opening while the edge of your flint is destroyed( bashed). Frizzen springs are also called " Feather springs" because the tension on them is so small. Most frizzens weigh less than 8 oz, even on a large Brown Bess style lock. A Pistol lock is so small that the frizzen weighs in the 4 oz range. The tension of the frizzen spring should be no more than 1 lb., AND the frizzen spring should allow the frizzen to snap or pop open as soon as it is hit. The little foot that rubs against the spring is called the " cam" or "heel". That cam should be polished mirror smooth, as should be the surface of that spring arm where it makes contact. The pivot pin/screw in the lock that holds the frizzen in the lock should be well lubricated so that the frizzen moves freely. Lube the contact points on the spring and the cam. I usually find that cam has burrs, or casting lines, and is rough as a corncob! stone those off, and polish. I also find on some frizzens, that the cams have a very wide bearing surface that sits on the spring. I grind or file the bearing surface so that its no more than 1/32" from front to back, as you look down the barrel. This compares to a woman's high heel, and that of a man's much larger heel. In this case, we WANT the cam to move out of the way quickly after it hits. The metaphor to a woman's heel would be, "we want the woman to slip on the ice!"
Many springs "climb" after the cam contacts the spring, making it necessary to compress the spring further to get the frizzen open. This is a poor design problem. The fix is not easy, if you have to contemplate softening the spring, then reshaping the arm, and then rehardening and retempering the spring.
However, I found a better way to change those darn spring. They are usually relatively thick at the point where the cam contact the spring. I remove the spring after marking the exact location where the cam rests on the spring when the frizzen is close, and grind/sand a small, shallow dish, or " pothole" in the spring just to the rear of where that cam sits with the frizzen closed. With the alterations I describe above to limit the amount of contact between the cam and the spring, this Pothole allows the cam to swing out over open air, which in turn allows the frizzen to immediately respond to the pressure of the flint to "POP" open, before the spring arm can rise sufficiently to stop that movement. The dish is less than 1/4" the thickness of the spring. The filing, grinding,sanding of the spring is down at slow speed, to keep the heat down, and is always done with the length of the spring, NEVER across the width of the spring. I polish that "dish" to a high gloss finish, too, using emery cloth.
Even using a heavy mainspring, this modification of the cam, and frizzen spring will save flint life. But, the angle of impact has to be there, also. Again, I want the tension on the frizzen spring to be about 1 lb. It will often begin at over 5 lbs. on these guns.
The mainspring tension should only be 10 lbs. They often are more than 30 lbs. The bottom arm of the mainspring is the working arm, so its where we do some reduction, using grinders, sanding discs, or files. I hold the spring in my bare fingers so I know if the piece is getting to hot as I grind down the side of the arm.
I begin by drawing a line from about 1/2 inch down from the bottom of the "V", to the outside edge of the hook at the end of the arm. The hook is that curved piece that actually rides on the horn of the tumbler. If the lock in your gun has a stirrup and pin arrangement, I just pick a spot about 1/2 to 1/3 the width of the spring, so that I can thin the width of the spring arm to reduce its strength. I draw a line between the two point. The then begin removing metal on the outside of the line. Periodically, you test the spring to see how much reduction in tension has been achieved.
I describe this process in an article that has been republished here under " articles," up in the member resources section of the Index page to the forum. The Article is titled, Shooting and Tuning flintlocks, but is index as " shooting flintlocks, or something short like that. Basically, I use a trigger pull gauge to measure the tension on the frizzen; I use a common bathroom scale to measure the tension of the mainspring. I wrote the article so that all owners of flintlocks can TUNE the locks on their own guns.
You want to smooth out the face of that frizzen. With the cock angled properly, the flint will scrape steel bits off the frizzen and not gouge them out, leaving ruts. It the ruts that destroy more and more flint edges, and make it impossible to get hot sparks, much less have the flint throw them down into the pan. Get rid of the RUTS, and Chatter marks.
Chatter marks are caused when your chosen flint wrap allows the flint to BOUNCE, or rebound off the frizzen when the flint edge first strikes the frizzen. The problem is exacerbated if the angle of impact is too square( between 90 degree and 60 degrees) or if that feather spring prevents the frizzen from popping open. In time, the frizzen begins looking like a washboard!
Tuned, and with the flint striking at the correct angle, you should see only long scrape marks on the face of the frizzen, and can forget about polishing and smoothing the frizzen ever again.
I give tips on how to prime the pan, use a vent pick to open a hole in the main charge, through the vent, and how to choose your powder granule size, and how to load the powder into the barrel to speed ignition of the main charge.
The article in Muzzleblasts about lock speed between flintlocks and percussion is limited by the testing equipment, to test the time from when the hammer begins to fall, to the time the ball leaves the muzzle. Unlike a percussion cap, which forces fire into the powder charge, and ignites most of the powder quickly, at very high temperatures, a flintlock is more like a cannon fuse. By leaving a hole in the powder so that the heat from your burning priming powder is allowed to ignite many granules of powder all at once, rather than one or two at the vent opening, you increase the speed at which the main powder charge in any flintlock ignites, heat rises, pressure rises, and the inertia of your projectile is overcome so that it begins moving down the barrel. I find that unless you are shooting a very heavy RB, the inertia of smaller caliber guns is too little to reach proper chamber pressures to insure complete burning of the powder. So, I always recommend that an Over Powder Wad ( OP Wad) be used between the powder and your PRB. This slows the movement of the ball in the barrel just long enough to raise the chamber pressure and temperature to produce more gas, and launch the ball at a faster velocity.
The fallacy in comparing percussion pistols to flintlocks is the belief that because they shoot the same diameter balls, and the same patch thickness, and use the same powder, that they should fire the same. These are two different ignition systems- one very open, and the other semi-closed. If you understand this, and load the gun accordingly, you can achieve extraordinary fast ignition with a flintlock. I believe a fairer test for ignition would be from the time the hammer begins to move to the time the prime( cap or powder) ignites. I know that the priming powder, in a tuned lock, will fire faster than the percussion caps. And, if the barrel is loaded properly, the difference in times that the ball leaves the flintlock barrel will be on par with that fired in the percussion barrel.
I have had several BP shooters come down the range to ask me if I am shooting a Percussion gun, rather than my usual flintlock. When they see I am shooting a flintlock, they want to know how I get the gun to fire so fast. They are used to hearing un-tuned locks that go: " Klatchf-f-f-ftBOOM", and are not expecting to hear my gun go "kBOOM" when I fire a round. I will concede that even I don't hear any separate sound of the hammer hitting the percussion cap and nipple when I fire my percussion gun. If everything is working correctly( I tune my percussion locks, too) I hear only a "BOOM".
Don't accept what the manufacturer sent you, and think its working as it should. You can tune that lock to perform so much better you will find yourself crying at the range. Let me know if I can help you with any questions, or help walk you through the process. :thumbsup:
