Slow flintlock ignition Part 1

Darkhorse

Senior Member
The biggest culprit in slow ignition speed in the flintlock is the Touch hole. There is also a lot of theory, legend and myth associated with this subject.
For instance; “Bank the powder away from the TH for faster ignition and to prevent the fuse effect” So, is this a myth? “Not necessarily”
How about a legend? “Again, not necessarily, but it most likely is.” Confused yet? More on this later.
In an earlier post I described a new shooter being overwhelmed by the all the neat stuff going on in front of the eye and the noise “ Ker-latch ssssssss Boommmmm. In truth this is noise most shooters hear and is fairly accurate to the new gun. But if your gun sounds like that then it’s really sloooooowww. What it should sound like is this; “ ch..BOOMMMMM!” The sound of the flint striking the frizzen and the main powder igniting should come so close as to almost be one sound.
When your rifle sounds like this then it’s close to being really fasssst!
Why is this? In the present time as in antiquity a lot of touch holes really were lacking in design. Below is an illustration of the typical production touch hole liner found in many rifles and in some custom guns.
PRODUCTION LINER.jpg

Some are worse. The flash hole is often at the bottom of a screw slot. The touch hole size will be too small. And the cone will not be deep enough to serve it’s own purpose. Back in the day I reworked a lot of liners with this type geometry. The cone was enlarged and lengthened as deep as possible. The hole was drilled out to optimum size. And I would use a little ball endmill to cut out the very center of the screw slot down to the face of the TH (touchhole). Reason being, sometimes it’s just difficult for the fire to find the actual touch hole itself when it’s hidden by steel.
Below is an illustration of a modified TH liner.
MODIFIED TOUCHHOLE LINER.jpg

I do the chamfer because MY theory is it helps direct fire into the flash channel.
Notice the enlarged cone. This gets a lot of main charge real close to the TH. Simple; The more powder your prime can ignite the faster your total ignition time will be.
The flash channel should be as short as possible and still leave a little flash hole length. I want mine under 1/16” long. This allows the fire to kiss more of the main charge at once and quickly.
When all this is done it’s time to go shooting. I fire a couple of shots to gauge the speed. Then using a set of number drills I drill out the flash channel one size at a time until I get the desired results. Number drills are small drill bits that are graduated in thousandths of an inch instead of fractions. For instance with regular drills if I go from 1/32 to 1/16” I am increasing the diameter from .032 to .0626 and the circumference is increased exponentially (too much).
With number drills I can increase the size by .004” and try it. Remember the circumference also increases and now you have much more surface area to ignite. Remember this also; “You can remove metal easy but it’s much harder to put it back on.” So keep those drills small.
Example: Jim Chambers excellent White Lightning TH liners comes with a .055 hole. For .40 and .45 I find that .062 works excellent. For a .54 where I want reliability and speed a good starting point is around .070. These actual figures depend upon your actual gun and TH liner geometry so experiment a little. Don’t make your hole so large that your main powder wants to self prime your pan. A couple of grains trickling out is alright. The smaller the grain (FFF) the smaller the hole.
Mr. Chambers liners also have a cone with radius shape to them. Like a shaped charge. Unfortunately these don’t come in removable versions or metric threads. Your barrel must be drilled and tapped, the liner installed, then the excess cut off and hand worked down to flush. It is very much worth putting out a few bucks to have this done.
A couple of years ago I fitted a liner from Rightnour to a new Pederosoli flintlock.
http://www.rmcsports.com/
I drilled it out to .062 and I was really surprised at the speed of this rifle. Not to say it couldn’t have been opened up another drill size but still it was a surprise. The Pederosoli’s have a large lock with true flat springs instead of coil springs. Sparked really nice.
It’s been a couple of years since I bought one of these but order one or two and if they haven’t changed the design you will have the starting point for very fast ignition. These things already have all the mods done to them I used to do years ago.
How about the prime? Well timed tests show 4F is faster than 3F but I really, really doubt a human being can detect the difference. So if you’re out of 4F don’t stress yourself out, just use what you got.
Now back to the Myth/Legend of banking your powder. A fellow named Larry Pletcher has developed some cool techniques for timing anything imaginable that has to do with a flintlock and speed. He gives his data in a format right down to the thousandths of a second. His tests show that banking the powder against the vent is actually faster than banked away. How about that?
Before anyone gets into a lather over this sacrilege of legend allow me to explain something: His tests were done with a well designed TH with a predrilled vent. In a well designed vent it doesn’t matter where the prime is located. If against the vent then it simply becomes one with main charge causing instantaneous ignition.
On the other hand, how about the hangfires we ALL have experienced which cause us to shake the prime away from the vent, and which we know Ol Davy and Dan’l also experienced. Causing the legend we know and have experienced concerning banking the prime. Simple. Consider illustration #1 for a second. This long flash hole is really a tunnel. And when the tunnel fills with powder it must burn through that powder in order to ignite the main charge, which causes hangfires or delayed ignition (if it shoots at all). Hence the “Correct” thing to do is bank the prime away.
Now look at illustration #2. Notice the tunnel is gone and it now is a window from the pan to the main charge. Nothing to burn through. When the sparks hit the prime it all goes off right away.
And that is why I say; It both is a legend and is not.
 

choctawlb

Senior Member
Darkhorse,
That is some real neat information you posted . Real good illustrations, and some great tuning tips. Thanks for sharing em with us folks that shoot "Rock Locks".
Ken
 

FERAL ONE

Shutter Mushin' Mod
i have read this several times with interest and when i get brave enough i will start tweaking my thompson. it has the flat surface with no bevel whatsoever. this makes perfect sense and hopefully will make a pretty good shooter into a great shooter. thanks for the tutorial !
 

alex 4922

Member
Thanks for the info..I want to try a FL soon.

A
 

kvistads

Member
There isn't a better touch hole liner than the Jim Chambers' "White Lightning" liner. I discussed putting a slight champ-fer on the front of the liner many years ago with him and he said not to. It opens the hole up too large. The White Lightning liner is without a doubt the fastest liner available - period. I challenge anyone to compare.
 
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mmarkey

Senior Member
White Lightening Touch hole liners

I agree with Russel. I think they are the best and use them in all the rifles I build.

Michael
 

Darkhorse

Senior Member
Chill out guys. This little treatise wasn't really written for sophisticated flinters who already know all this stuff. But for those new to the flintlock, most likely with no one to help them smooth out the rough spots.
There are more factory rifles with removable liners out there that get tossed into a corner than custom flintlocks with White lightning Liners. Hence the explanation of how I used to modify poorly designed screw in touchholes, and the reference to RMC sports that sell metric and decimal threaded liners already modified.
True, there is a lot of debate (for people with nothing better to do) about the value of a chamfered touch hole. But for a chamfer to increase the size of the touch hole itself it would need to be cut by a drill press. I chamfer mine by turning the countersink with my fingers.
Granted not everyone has 40+ years in the Toolmaker and Aerospace manufacturing trade so some things I say lightly perhaps I shouldn't mention at all.
I've never read it mentioned but the idea of drilling out a touchhole with number drills came from an employee of Mr. Chambers when I called several years ago with a problem. At that time the chamfer was not thought to be a bad idea.
There is a lot more to the concept of flintlock ignition speed than I've written here. I was given a short but effective course on lock tuning by Mr. LC Rice and believe me, trying to convey the delicacies of lock tuning to the uninitiated does not bear contemplation by me.
So, to me, trying to show a way to improve the ignition through only one variable made more sense than anything else at the time.
But I suppose an open forum always invites disagreement on large or small issues.....
 

mmarkey

Senior Member
One thing that should help you out if you have an non custom built factory flinter. Take out the lock and carefully dismantle it, careful not to loose the fly, and polish ALL the bearin points and the inside of the lock plate with progressively finer grit papers till it's mirror bright. Not to make it look pretty (although it will) but to make is SLICK as a baby's bum. Carefully reassemble and oil everything and I use a little dab of CHOKE LUBE around the tumbler and mainspring bearing points. If you happened to notice any scratches or wear points concentrate on these first. This should help to speed up the lock action a bit and help it spark better.:cheers:
 

Redleaf

Senior Member
Good information here by everyone. I'll throw another tip into the mix concerning frizzen steel and hardness. Its possible to "cook" so much carbon out of the steel in the hardening process as to make it where it wont spark at all or spark poorly. The level of hardness is a primary factor too. Too hard and its liable to eat flints or quit sparking too frequently, too soft and it'll let the flint stab into the frizzen and stop or gouge a depression into the face. The geometry of various locks is different too, causing the flint to strike the frizzen at different angles and vertical locations. Some of that can be resolved by determining if the lock works best with the bevel on the flint up or down. You can bend the cock to change that angle too. So all you first time flinters who are going out next week to kill a deer, check all this information and make the necessary adjustments. :) So much of this kind of stuff falls into the category of "significant, but meaningless" If you dont practice and learn a pronounced followthrough, you're probably going to miss.
Keep your prime dry and relax.......................but not too much. ;)
 

badbull

Member
WOW! Lots of info for a novice flint locker! I shot my first hog and deer with a cap lock at 15 and I'm still using cap locks at 54, just haven't had the gumption to try a flint lock!
 

Darkhorse

Senior Member
There isn't a better touch hole liner than the Jim Chambers' "White Lightning" liner. I discussed putting a slight champ-fer on the front of the liner many years ago with him and he said not to. It opens the hole up too large. The White Lightning liner is without a doubt the fastest liner available - period. I challenge anyone to compare.

I haven't re read this post in years but just to show there are different ways to approach the same problem here's one example: When I built my first rifle and had just installed a White Lightning liner I called Chambers Flintlocks to talk about the liner. I didn't talk to Mr. Jim but one of his employees and this is what he said, "The touch hole is left small on purpose, shoot your rifle as it is first and judge the speed and reliability, if not to your satisfaction use #drills and drill it out one size up. Shoot your rifle again to see how it works now. If you need too drill it out again one size up until you get what your after then finish up by lightly chamfering the outside of the touch hole.
So we get 2 separate instructions from the same shop. Both work I guess as my rifles all have a chamfer while others don't.
 

Darkhorse

Senior Member
One thing that should help you out if you have an non custom built factory flinter. Take out the lock and carefully dismantle it, careful not to loose the fly, and polish ALL the bearin points and the inside of the lock plate with progressively finer grit papers till it's mirror bright. Not to make it look pretty (although it will) but to make is SLICK as a baby's bum. Carefully reassemble and oil everything and I use a little dab of CHOKE LUBE around the tumbler and mainspring bearing points. If you happened to notice any scratches or wear points concentrate on these first. This should help to speed up the lock action a bit and help it spark better.:cheers:

THIS! When I first built my rifles I did a half*** job of this. It worked, but I kept noticing my .54 sometimes had a slightly slower ignition, noticable to me. I intended to try and do something about it but never did.
But one year after deer season I made a list of things I wanted to do and one of them was re tuning my locks.
I did it mostly how MMarkey described it except first I checked my lock plate for straightness, it wasn't, it had a couple of bowed spots, so I straightened it. Then started on the locks. Both rifles also had developed a case of wobbly frizzens. The results were much better than I had expected.
The rifles both had faster ignition. The one with set triggers had hardly any delay and it smoothed out the whole process by eliminating the "jar" sometimes associated with set triggers.
My deer rifle had a single pinned trigger and I was perfectly satisfied with it. But I put a trigger scale on it and found that when the lock was slicked up there was no creep and the pull actually decreased a good bit.
That's the only way I could think of to try and measure the results of my re tune.
It is worthwhile to spend the time neccessary to slick up your locks.
 
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