Correct Flint Angle

[Carl Fowler III]

Watched some high speed video footage of numerous flint locks being used...what an eye opener, seems it was rare for the flint to create any spark at all until the flint was at the very end of the frizzen! Also saw where some frizzens actually opened fully and then kicked back and hit the flint(assume the frizzen spring was to stiff....this seemed to happen more often with frizzens with bearings) over time this has got to damage the flint itself. Also noted that some of the pans were not getting the sparks centered in the pan but more to the front of the pan. When centered in the pan the powder charge ignited more quickly...these locks were mostly top of the line products I've seen mentioned on this forum...Siler, L&R....this H.speed video was on u-tube @ BlackPowder MAG.com...please take the time to watch these video's before responding to this post.

So my question is this: why should it be so important in placing the flint so it makes contact with the frizzen high up on the frizzen...dosen't it seem better to be midway down on the frizzen(faster lock time) creating better accuracy? :hmm:

 

[hanshi]

To get the most sparks and the best flint life the flint edge should be situated to scrape down the frizzen face at roughly 60 degrees + or -. If the flint hits too head on it will gouge the frizzen face and damage the flint. Still, you want as much of the frizzen face scraped as possible while maintaining this correct alignment.

 

[Larry Pletcher]

Because of the very strong lighting needed to take the videos, you are not seeing the majority of the sparks. Some of these were shot in my garage in Jan 2007.The others were shot at Friendship in 2007 and 2009. The minimum that we used was 600 watts, in some cases an extra 400 watts. Those that you see that were hand held in 2009, Dave needed to use gloves to keep his hands from sun burn. At any rate, judging the spark production from the video is unreliable.

To get an idea of the real spark production of these locks, take a look at the stills done in the article on "lead vs leather test". Here the lighting is normal and gives a real view of spark production. I'm at the wrong computer to post the pics here, but you can see the difference.

Back to the videos, one thing that surprised us was that the sparks do not accelerate off the frizzen strike. They appear to roll down the frizzen just below the flint edge. Another surprise was that in frame-by-frame advance you can see that the cock neck flexes for 2 frames or so, after it hits the stops.

Regards,
Pletch

 

[Carl Fowler III]

Agree lighting would affect the sparks viewed...so if the spark chards rolling down the frizzen are released toward the end of cycle,which way would you want to place the angle of the beveled edge of the flint...(edge angled up"/" or edge angled down"\") appears to me angled down would give a quicker lock time? Angled up would give more spark but be slower in relation to lock time, as the sparks aren't dumped into the pan till frizzen is cleared! :hmm:

 

[Carl Fowler III]

My bad, should have gone back to the site and checked out the lock time testing you've done....hats off to you and the through testing done...after reading it in it's entirety all questions answered! :thumbsup: Although I didn't agree with you throwing out the pan powder of 3f for 4f due to an anomaly diviation with 4f! :bow: This could be why some like to use 3f over 4f when humid conditions exists, which is why it may not have been an anomaly but more a standard?

 

[Larry Pletcher]

Agree lighting would affect the sparks viewed...so if the spark chards rolling down the frizzen are released toward the end of cycle,which way would you want to place the angle of the beveled edge of the flint...(edge angled up"/" or edge angled down"\") appears to me angled down would give a quicker lock time? Angled up would give more spark but be slower in relation to lock time, as the sparks aren't dumped into the pan till frizzen is cleared! :hmm:

I don't think you can make a hard and fast rule about bevel up or down. I usually time a lock 20 tries each way to see what a lock likes. Sometimes bevel up is clearly faster; sometimes bevel down is faster. Sometimes there is no statistical difference.

Differences in the geometry between locks play a big part in this. The angle of the flint hitting the frizzen is important, and at times a shooter will need to change the bevel or even shim the flint up with an extra piece of leather to improve the angle. How far the flint is away at half cock makes a difference. Many possibilities here.

Regards,
Pletch

 

[JCOPE]

I've diddled with the angle up/down. Goes BOOM either way. I prefer angle up, just because.

 

[Dphar]

Historically bevel down is correct.
My rule of thumb is if the lock works best bevel up it needs to the corrected.
But others disagree.
I shot flintlocks for decades before I even heard of anyone putting the flint in upside down.

Dan

 

[Larry Pletcher]

Historically bevel down is correct.
My rule of thumb is if the lock works best bevel up it needs to the corrected.
But others disagree.
I shot flintlocks for decades before I even heard of anyone putting the flint in upside down.

Dan

Dan,
I noticed this when studying Neal's book Best English GunMakers 1540-1740. Almost every lock pictured has the bevel down. I really had no preference before, and still set the bevel based on timing the lock both ways. I think it's interesting that the "best English makers" based their lock geometry on a bevel down philosophy.

"Mind you vent liner",
Pletch

 

[M. De Land]

I'm new to flintlocks so just sorting stuff out myself as I listen to what others have to say as well.
Seems to me which ever way you run the bevel the frizzen is going to develop a wear pattern to that arc radius and should keep getting more efficient as it wears into it.
It also makes sense to me ,at least, that the lower on the frizzen you make the wear arc in the frizzen face than the closer the spark shower is going to be to the pan.
I would think this would both increase speed of ignition and reliability.
The bevel up, sharp edge down reduces the swing arc of the flint edge,makes it impact lower on the frizzen and would make the wear arc closer to the pan. It would also sharpen the strike angle lessening the impact pressure on the flint edge and probably increasing it's longevity as well. MD

 

[ebiggs1]

A not nearly sophisticated test as Mr. Pletcher, but that almost anyone can do is with a cheap video camera, is this.
Most shoot frames at 1/30th of a second. There is software, some free, available that allows you to see frame by frame. This means you are looking at 1/30th of a second slices of time.
This is a Lyman, not considered a good lock by many, without the cock fix. But it shows even a poor lock like the Lyman does indeed produce good sparks right where they need to be.

 

[ebiggs1]

Those that you see that were hand held in 2009, Dave needed to use gloves to keep his hands from sun burn.

I used to use “hot” lights, too. Big halogen bulbs and big reflectors but................... :td:
After getting many complaints from young ladies sitting for their Senior pictures, I switched to the new florescent lights. They don't get hot and they are available in several different temperatures Kelvin.
No “sunburn” or gloves required! :thumbsup:

 

[ebiggs1]

A couple more photos that are not as easily done because of better equipment required.
Some with strobe and some without but you can clearly see the spark production from a L&R lock.

As you all can see from the last posts, I am favoring bevel up. It seems more logical that the angle to frizzen is better with the bevel up. Everythng else being equal. :wink:

 

[Larry Pletcher]

I wish more shooters would try this. It is possible to do this with inexpensive digital still cameras. Almost all have a setting to hold the shutter open for a a few seconds. While camera is stationary, open shutter, snap lock, wait for shutter to close. You will be able to see, as in ebiggs pics, where the sparks land. I think this is one of the most important things to know. Ive seen locks that made many sparks and placed most of them in front of the pan.
Regards,
Pletch

 

[hanshi]

I generally install flints bevel up because in most of my locks this puts the flint at the correct angle to give a good, long scrape down the frizzen face. As the flint wears it gets seated out farther and maybe flipped bevel down; just depends on the angle I get. Now some locks and some flints sizes have their own ideas how they want to be installed. Mostly I give them what they want.

 

[MSW]

thanks to Pletch (if i haven't already said so, please forgive me) for his excellent work ... he's putting some very valuable information, and some very expensive technical expertise, and the use of some hyper- expensive equipment out there for all to see, and he's doing it all for free.

so, a big huge :thumbsup: :thumbsup: :thumbsup:

and a giant :hatsoff:

to him!

 

[Larry Pletcher]

MSW,
Thanks. You're very kind. You do know that the expensive equipment was borrowed from Olympus Industrial. They actually sent a tech guy along to keep it safe.:grin:

Regards,
Pletch

 

[Carl Fowler III]

Still Pletch, thank you for this insightful and expert look into the why's and wherefores of the mysteries of how a flintlock works! So many bring to the table what they have been taught from other's, not really knowing if it holds up under scientific scrutiny, where you had the inquisitive mindset to actually seek out the truth of such matters! Don't usually :dead: but in your case felt it was necessary! :hatsoff:

 

[tenngun]

I have shot with bevel down until the flits been shot napped and shot some more then fliped over and shot some more.Now I do blow down my barrel tween shots,but... I dont think that effects flint life or angle of attact :haha: