Bevel up/Bevel down

[Acer Saccharum]

Yes, we have all had this discussion at one point or another. The usual method is to place your flint so that the lock sparks the best, and that's how your flint should be installed. Right?

I was reading this topic over, and several members are talking as if BEVEL DOWN is the way to go. How ca this be? Gary Brumfield says the English lock was designed for bevel down. Dan Phariss says flint will not flake properly bevel up, because of the grain structure of the rock. Filipski says flint will self sharpen when mounted bevel down. Pletcher chimes in and says he gets most consistent results with bevel down.

Both Phariss and Filipski say that if a lock won't work bevel down, they fix it so it does!

Inconceivable!


My question is: If one were to go about 'fixing' his lock, what would that look like? What does it mean?


Regards, Tom

[MikeCooper]

mine sparks better bevel down.  Both my siler and my old jager.   it hits the frizzen much higher up also.  bevel up it hits the frizzen almost in the center so not as much distance to make sparks.       Try it both ways and see which works best

[Jim Filipski]

Tom,
 Mellow out.... I know it hot here in the Northeast.
Simply stated the geometry of the lock determines how far out and at what angle the flint hits the frizzen. Now this can be altered in a pinch by the addition of a thicker piece of leather to wrap the flint and the lower area of the wrap can be skived thinner to drop the flint edge down. Also the very important "cut out" in the center back of the leather wrap ( which allows the flint to sit further back in the jaws should not not forgotten.
Many locks in the 80's & 90's had bad cock geometry. ...heating the cock neck & bending to change the angle was the cure. I did this with a lot of the Davis large locks back then ....I don't have to now!  The folks that are making good locks now seem to have improved this.
I have a few large silers from the 80's  the normal 3/4 inch English flints sold today stick out too far bevel down ( I think they even started knapping them longer because of this change & some others use of bevel up!  Anyway I have to go so far as to re-knap or knapp off the backs ....& when they do they last a long time.
I don't have a scanner here but when I go to work I will draw up a diagram  to illustrate  how it is possible that during firing the flint sharpens itself when bevel down. It has to do with the knapping angle and the way it will strike the steel.  If you imagine it in your mind you can almost visualize how the flint chips itself during it's downward travel.
More later
Jim
Jim

[Mike Brooks]

I have been shooting flint guns for 30 years bevel up.

[northmn]

Like Mike I have always fixed things so the gun works better bevel up, even to bending a few ammers.  Seems like the flints last longer that way as they may knap too much.  Shot a few years that way also, no problem.  Some flints last longer than others, etc.  A lot of flintlock shooting is in getting a good flint.  Whether English of Missouri I ahve picked out some that looked good and only lasted a few shots and others that seemed to last indefinitely.  Which works better depends on lock geometry, but that can be altered for flint position.

DP

[rich pierce]

I tend to agree that flints will self-knap better bevel down.  This way the flint maintains a chisel edge (one side flat, the other side beveled) instead of a knife edge (bevels on both sides, ultimately resulting in a more obtuse angle).

Also with some locks, when a bevel up position is used and the flint shortens, the top jaw or the top jaw bolt will begin to strike the frizzen at the same time as the flint.  This rarely happens with the bevel down position.

[northmn]

An old dog may have to try a new trick.

DP

[Keb]

I've had better luck with bevel down. As far as knapping, I made this little device.

Just place the step on the dull edge and whack it on the top. The edge is as good as new.

[Jim Filipski]

Sorry for the chicken scratch diagram:


On the initial hit of the flint it starts to throw the frizzen open and contacts very close to the original knapping angle. Instantly the angle changes and cuts steel for spark

[Acer Saccharum]

How does one 'fix' a lock to spark better bevel down?
JWF: bend the cock.

[Jim Filipski]

One word of warning. The way many flints are knapped now a days .... I see them many times too long when bevel down so be careful you don't embed your flint into your pan!

[Mike Brooks]

Generally I have noticed that with the bevel down the sparks tend to mostly fall ahead of the pan slowing ignition. With the bevel up the flint chucks sparks sharply right into the pan for quick ignition.
With bevel down you tend to strike the entire face of the frizzen.
 With bevel up you strike the bottom 1/2 to 1/3 speeding up the whole process. I'll not be easily convinced to change my ways.

[Jim Filipski]

How does one 'fix' a lock to spark better bevel down?

Look at the angle of the cock in profile when the flint engages the frizzen. You can judge  how much to bend.
Make a template ( out of sheet brass) if necessary.
Somewhere in my shop I have templates I made for Davis locks from the 90's French, Early, etc
 I have a few other odd balls there too  If I find them I will up load the adjustment angles

However I have recently used some new versions of these locks and it seems they work now as bought..

[Larry Pletcher]

. . . . .  Pletcher chimes in and says he gets most consistent results with bevel down. . . .
Regards, Tom

Tom,
I went back to see what I said about timing bevel down.  The L&R Durs Egg was the lock that showed a marked preference for bevel down.  I also said that I had not timed a lock since that showed that much preference.  I used that lock as a single example.  I have photographed spark production bevel up vs bevel down and usually can't tell the difference.

As far as "gets most consistent results", currently all the locks I shoot have flints mounted bevel up.  My old workhorse Siler that does all my testing is used bevel up.  I really don't have a dog in this fight.  My initial reaction to the book on English makers was one of surprise at the majority of bevel down mountings. 

So, I'm all ears when it comes to the geometry discussion.  I often learn best when a discussion like this comes along.

Carry on!
Regards,
Pletch

[Jim Filipski]

Generally I have noticed that with the bevel down the sparks tend to mostly fall ahead of the pan slowing ignition. With the bevel up the flint chucks sparks sharply right into the pan for quick ignition.
With bevel down you tend to strike the entire face of the frizzen.
 With bevel up you strike the bottom 1/2 to 1/3 speeding up the whole process. I'll not be easily convinced to change my ways.

First off I want to address Mike: You are right on there.......that's what happens "before the cock is adjusted" It will tend to spark too far forward of the pan and hit too high on the frizzen. The adjustment changes this Now for the next part
You are right again. If the darn thing works for you don't stop using it!   ( however we do need things to hash over as topics on this list!)  

[Jim Kibler]

I don't think the angle between the flint and frizzen is significant when going from a bevel up to down position.  It's still a relatively sharp corner striking the frizzen.  Putting how it self sharpens aside, who cares what's behind the sharp edge.  The biggest factor in my opinion is where the flint strikes the frizzen.  What you are doing when changing from bevel up to down is effectively lengthing the cock.  Think of the distance from the tumbler pivot to the leading edge of the flint.  Depending on the lock and flint geometry, one orientation might work better.  In my experience, I don't want the flint to strike too high on the frizzen, but also not too low.  Each lock will have range that seems to work best.  Again, this can be effected by position of flint in cock and the length, height etc. of the flint.

[Jim Kibler]

One additional comment...  By bending the neck of the cock downward, the throw is being decreased.  For each lock geomentry there is a range in this distance which seems to work best  To further cloud the issue, as the length of throw changes, the angle of attack between the flint and frizzen is changed slightly as well.  So to summarize, in my opinion the critical factor is having the length of throw ideal for the lock geometry you're working with.  If the lock geometry allows a bevel down position, it may tend to self sharpen better.

[Acer Saccharum]

Larry, sorry if I mis-quoted you; I am just trying to start a dogfight: get Filipski and Dan going about something sparky. The plan is to ask some questions, play dumb(easy to do), then sit back and watch the comments and suggestions roll in.

I think it's a great topic, and it applies to both building and shooting, with a sprinkle of history.

What about the curving of the frizzen, or making forged mainsprings for a snappier action, lightening the cock, etc?

Tom

[Jim Filipski]

Oh, I don't know Acer  ....it's hot & I'm cranky & tired and I still have contract guns to build ( I'm never going to get to my own stuff)

However I always like to listen in,  throw in 2 cents, get new ideas & never used them cause I'm too stubborn and set in my ways 

But for two more cents worth, I think the curved frizzen face only adds to the sharpening effect by engaging the flint face at a better angle for a quick "Knapp" on it's travels to make sparks!
Maybe Larry can check his English locks to see if the ones with the protruding top jaw also has a more curved frizzen?

We that should keep us busy for awhile 

[northmn]

One thing Rick said that I have noticed is that with bevel up as the flint wears you tend to get the bind between hammer and frizzen.  However I merely lengthen the grip on the flint and remove that problem.  The flint does not have to touch the back of the grip.  When I bent the hammers I always did so, so that the flint would center on the pan, which was recommended for getting better ignition.  many years ago I had an article on tuning flintlocks and pretty much followed what was said.  The big trick is to get the sparks hitting the pan.  Some locks may do bevel up, others down.   I do think the bevel down may hit a little higher on the frizzen whcih may help to kick it open?

DP

[Acer Saccharum]

Jim, anything to keep Pletch busy is a good thing. If he's not working on flinters, his roving eye might turn to old cars.



Curving the frizzen, hmmmm. Are we looking for a shearing action in a flintlock? The word 'frizzen' comes from a German word that means 'to mill', I believe. We are shearing steel off the frizzen with the flint. Lemme ask you this: What is the appropriate angle for best shearing?  I'd think by curving the frizzen face, this ideal angle could be maintained for a little longer than with a flat frizzen.






Wouldn't this be a good header for a magazine article? Bevel up/Bevel down? Has a nice ring to it somehow.

[Jim Filipski]

Jim, anything to keep Pletch busy is a good thing. If he's not working on flinters, his roving eye might turn to old cars.



Curving the frizzen, hmmmm. Are we looking for a shearing action in a flintlock? The word 'frizzen' comes from a German word that means 'to mill', I believe. We are shearing steel off the frizzen with the flint. Lemme ask you this: What is the appropriate angle for best shearing?  I'd think by curving the frizzen face, this ideal angle could be maintained for a little longer than with a flat frizzen.

I'm not a math genius but I think what you said is correct. If the "Magic angle" is correct on first contact,  the curved face should hold that angle longer in the flint's "Shear" towards the bottom

Wouldn't this be a good header for a magazine article? Bevel up/Bevel down? Has a nice ring to it somehow.

Please don't bring those Guys back again!

[Long Ears]

I seem to have the best luck with bevel down on two Chambers Large Siler locks. I have tried bending the cock on one of them after carefully tracing the original angle. I ended up going back to factory settings as usual for the best rock life. I had an L&R that ate flints but had good spark I tried everything short of sending it to someone to tune. I sold it to a guy who wanted a cool looking wall hanger and occasional shooter. I'm hoping you guys will figure out the perfect geometry soon. Than I can quit trying everything I read. Sure is fun learning all of this. I wonder how long it took to get it correct in the old days, when your life depended on that rock and its spark. Bob

[Acer Saccharum]

Mankind put all his combined energy into getting the most reliable ignition with a flint. Now mankind has switched his focus to iPhone development. The development of the perfect flintlock took hundreds of years. Then it's obsolete in a wink.

But they sure are neat.

T

[Pete G.]

If you would develop a frizzen using the Golden Mean it would keep the topic active all summer.