vent hole size.

[carl lafong]

thanks everyone,.... slowly working to change a perc. to flint was thinking of the 5/16 x 24 thread for the vent hole , can I use the same barrel as the perc.
or is there actually a difference between the 2....... thanks to Cattman for the lead off............ carl lafong

 

[Cattman]

Zonie, that was very very informative. if i do a build for my self on a flint lock i will do as you described.

 

[M. De Land]

Thanks for the help guys. I'm going to monkey around with this one a bit more to see if I can learn something from it which may be what not to do! I did keep the WL liner just in case my big theory's turn out to be so much apple sauce.
My thinking in relation to the pan charge is that it is not a shaped or focused charge as is a nipple and cap but rather an open flash in all directions as the frizzen opens. The portion that hits the right angle of the barrel wall at the vent, one would think should be aided by the funnel shape just as water when poured into a container because of the flow focus and less turbulence at the hole entry.
It is true that flat faced exterior vent holes is the norm historically and as Zonie says there has got to be a reason for!
I have become some what jaded against WL liners as they always seem to direct more chamber pressure out the vent at discharge. I've been burned a couple of times by them at matches from shooters who did not know to put up a barrier between us and I didn't notice until I got the vent blast up side the head!
The other thing I'm experimenting with that works in my flint pistols is to load with a soft wire pick in the vent that insures an open flash channel for each shot. They seem to fire almost instantaneously. It looks like that each gun is a law unto itself and that some generalities seem to be consistently true but all the variables involved can make a common solution for all quite hard to demonstrate.
One thing that I'm convinced works for sure is keeping the flint face in good condition with a pressure flake touch up between relays!

 

[Darkhorse]

Many years ago, when I first began using the White Lightning, I called Chambers shop to ask a few questions. They put a man on the phone and we talked about the WL liners. To make this short here's what he said in a nutshell.
"The liner is drilled with a small hole. Take a set of number drills to the range and drill out the small hole one drill size larger, shoot the gun for speed and reliability. If the results are not what you want then drill it out one drill size larger and shoot the gun again. Continue doing this until the results satisfy you then shoot several shots to see if the results are consistent.
When you are satisfied with the size of the touch hole take a 45 degree countersink and turning it by hand, sightly counterbore the touch hole."
This has worked for me for over 20 years. My rifles are fast and consistent. But it seems everytime I mention countersinking the TH it upsets most people. Oh well, their loss is my gain. So much for the value of old wive's tales.

 

[Grenadier1758]

@Darkhorse , the number drills are a good choice for drilling the touch holes.

As you can see there are 5 number drill sizes between 1/16 and 5/64. Number drills are a good investment to have. Most times the #50 does the trick.

You did good by listening to the developer of the liner about the countersinking of the entry to the touch hole. What the counter sink does is to break the edge at the entrance of the touch hole. The hard edge breaks up the flow wave from the heat and slows the transfer of heat to the main charge. The countersunk hole makes for a smoother flow of the heat to the charge.

 

[Flintandsteel]

The secret to fast, reliable ignition, is to bring the main charge as close to the priming flash as possible.
Coning from the inside is the best way to accomplish that.
A white lightning liner does that for you. For smaller calibers, a smaller vent hole is advisable. A touch hole does release some pressure, and in a smaller caliber, that is more important.
Start small, and enlarge till reliable.
All but one of mine is 1/16”. My 20ga is almost 5/64”.

 

[GREENSWLDE]

Zonie at Post 19 follows the principle used by Many British gun makers of the late 18th & early 19th and some Europeans. Nock started using this in the 1790's and has not really been bettered. The Back screw or liner of about 3/8th"went thru' the Plug and was drilled thru' at about 3/16th" to within 1/16th of the face then thru' to the vent size. The anti side was then fitted with a screw to seal, which could be removed for cleaning. The Cone in the breach plug was drilled thru' to the vent plug at about 3/16" giving the True "Nock's" form breach. Many had the breach plug stepped in to bring the pan neater to the C/L of the barrel. Locks made to this principle are normally almost as fast as Cap guns. The pan side of the vent plug or touch hole face was always flat. I have never seen an original European or Brit. with the vent countersunk from the outside. I have been in the distant past been accused of cheating at flint events using my own locks on restored guns by people suggesting I was using a Caplock... OLD DOG

 

[hanshi]

1/16" will do it; got that on all of mine.

 

[M. De Land]

Well,that treatment with the diamond file in conjuction with the exterior cone worked. The rifle fired fast and reliably at the Territorial match I attended four days last week and over the week end. I had a lot of fun shooting it in the matchs and it is a keeper.

 

[M. De Land]

1/16" will do it; got that on all of mine.

Yes, that is the hole size I used which is .0625 but it didn't get really fast until I did the exterior hole cone with the tapered round diamond file. I was looking for another method to speed up ignition without the interior cone I do not care for. I had already tried a 60 degree cone on the outside of the liner keeping it smaller than what the frizzen wall would keep covered when closed which did not seem to help. Thinking about what Jim had said about the possibility of the 60 degree cone edge disrupting the plasma flow from the pan flash I decided to eliminate that corner with the tapered diamond file which comes almost to a point. This cleaned up that sharp bottom edge left by the 60 degree chaffering tool into the flash hole and sure enough both reliability and speed were greatly increased. I have become a flint enthusiast from this experience this week end. The very gradual taper on the diamond file did not alter the hole diameter all the way through the liner into the barrel powder chamber it only broke the edge at the bottom of the larger 60 degree exterior cone into the flash hole.
Odd how tiny alterations can make such a huge difference. It worked on mine but that may be a fluke, I'm anxious to try it on more flint guns to see if I'm actually on to something or not.

 

[Col. Batguano]

Darkhorse's modified vent liner intuitively seems like it would aid in speeding ignition, and increase reliability. Do we have any emperical data on such a modification?

 

[M. De Land]

Darkhorse's modified vent liner intuitively seems like it would aid in speeding ignition, and increase reliability. Do we have any emperical data on such a modification?

It also looks like it is tailer made to vector chamber pressure outward just as the WL does.

 

[M. De Land]

I have no idea if it is as fast of ignition as a WL produces without a test like Pletch does but it feels as fast as any other flint gun I've shot that is considered fast. My guess is that with the flash channel clear and on encumbered by any sharp corners that the flash travel of 1/8 inch compared to say 3/16s inch can't make a difference one could notice in practical application.
What will be interesting now is finding out how well the A-2 tool steel resists erosion as I am very satisfied with the speed and reliability of the experimental flash hole liner design to this point.

 

[Larry Pletcher]

Since my testing was mentioned I thought I should speak up. I did a number of experiments on priming powder, vent location and vent holes. All are found on www.blackpowdermag.com

The one is called "Touch Hole Ignition Timing" tested increasing sizes of vents in a barrel, not including liners. I include a summary, but also all the raw trials. Here is the link:
Touch Hole Ignition Timing

Another is a 6 part experiment called "Pan Vent Experiments". This times high and low vents and also where priming powder is placed in the pan. There are a couple of myths involved here. The link is to an intro with links to the Parts 1 through 6. Part 3 includes photos taken through the muzzle, showing how much fire gets into the barrel - depending on where the pan is primed. Here is the link:
https://www.blackpowdermag.com/pan-vent-experiments-an-introduction/
Another that may help is called "Priming Powder Timing" . For this article I timed priming powder from Swiss Null B to Goex ffg. Summary and raw trials are included. Here is the link:
Priming Powder Timing

I hope these links are a help.
Regards,
Pletch

 

[Tom A Hawk]

My first experience with White Lightening vent liners was on a 1" .54 Hawken barrel. Ignition reliability was terrible until I drilled it out to 1/16" and its been excellent since. The next two were used on 7/8" barrels in .40 and .50. In these barrels the original vent diameter has been working great. I guess it all depends....

 

[M. De Land]

Since my testing was mentioned I thought I should speak up. I did a number of experiments on priming powder, vent location and vent holes. All are found on www.blackpowdermag.com

The one is called "Touch Hole Ignition Timing" tested increasing sizes of vents in a barrel, not including liners. I include a summary, but also all the raw trials. Here is the link:
Touch Hole Ignition Timing

Another is a 6 part experiment called "Pan Vent Experiments". This times high and low vents and also where priming powder is placed in the pan. There are a couple of myths involved here. The link is to an intro with links to the Parts 1 through 6. Part 3 includes photos taken through the muzzle, showing how much fire gets into the barrel - depending on where the pan is primed. Here is the link:
https://www.blackpowdermag.com/pan-vent-experiments-an-introduction/
Another that may help is called "Priming Powder Timing" . For this article I timed priming powder from Swiss Null B to Goex ffg. Summary and raw trials are included. Here is the link:
Priming Powder Timing

I hope these links are a help.
Regards,
Pletch

Thanks Larry, it's time to go through the whole of your testing and write ups again. I so much appreciate all of your labor in the interest of finding out the truth about this stuff and seperation from the horse pucky even when I self generate it with side ways ideas that don't pan out.
I sure would be interested to see what difference, if any, venturi shaped flash holes and liners make.

 

[AZbpBurner]

I've long ago coned the inside of all my liners. A #51 (.067") hole gives all mine 100% reliable ignition.