hole size in torch hole

[hortonstn]

i know this has been covered but i can't seem to find it, i have a white lighting insert in my 45 i'm building it sure looks small what size hole should it be or should i leave it alone?
paul

[Black Hand]

Leave it alone and shoot it.  IF ignition is a problem, THEN think about opening it up...

[blunderbuss]

I've sure seen some originals opened up looks like they were carved out with a knife. Black Hand is correct if it ain't broke don't fix it

[omark]

but, lf you deem it necessary to open it up, most people use about 1/16 (.0625). i think thats about what the white lightning is. most dont go over about .070.   mark

[Curt Larsen]

I use mine as is.  It works fine.  Others on our forum suggest opening it to 1/16", but I don't see the necessity.  Go for it.

[blunderbuss]

In the for what it's worth category I've worked on some original blunderbusses that have a touch hole in it that you could throw a cat through and a very strong main spring,strictly a business gun. I've noticed that on military pistols too.

[WadePatton]

In the for what it's worth category I've worked on some original blunderbusses that have a touch hole in it that you could throw a cat through and a very strong main spring,strictly a business gun. I've noticed that on military pistols too.

autopriming yo.

[Macon Due]

Hortonstn
I guess I'm of the "If it ain't broke....Fix it anyway" school....I had TVM to drill mine to 1/16" before they shipped it to me. I now have it drilled to 5/64" same as my .36 Tenn. rifle.  If they make sparks...they fire!!
Macon

[David Rase]

I like to drill mine out to .067 or .070", that is a no. 49 or 50 drill.
Dave

[D. Taylor Sapergia]

I too, Dave.

[Dave R]

.067" is just perfect for me with just a little relived crown on the outside, Without the crown it is like trying to make that side pocket at an angle on pool table, That corner keeps the ball from going in the pocket many of times and therefore the square hole hinders some heat and sparks from going into the main charge and it makes it just a little faster and more reliable!

Dave R

[Acer Saccharum]

For guaranteed ignition, open it up to 1/8". It will go off in rain or snow, on horseback or from coach top. It will probably go off if all the prime has spilled out.

However, if you are building a target gun, you want consistent ignition and pressure. Too large a hole will destroy any hope of consistent pressure. Too small a hole will slow ignition.

The advice above is good: start with the factory hole size and see how it shoots. If it's not performing well, increase a little. Max size I use is .078, but I think that's a little big.

One of the most important factors is the length of the touch hole. Keep that as short as possible. You may install the liner a little shallow to get a short touch hole. As you open up the hole, you also increase the LENGTH of the touch hole, which slows ignition. Then you can follow Dave R's advice to put a little crown on the outside.

Tom

[Dphariss]

Like Acer said

Installed vent liner should look like this when loaded.


I try not to go over 1/16" larger is not needed IF the vent is installed right.

This is unloaded


Vents over 1/16 will leak powder from the main charge even with FF.

Dan

[volatpluvia]

Last time I competed with my yeager with smoothbore 62 and white lightning liner, I fired 28 rounds at passing clays, birds and rabbits.  They passed at ten yards.  That is when you need swift and sure ignition.  I had never modified the touch hole in my liner and it fired every time.  Only once during that 'round' of clays did I sense the slightest delay in firing.  It was a Getz heavy yeager and a chambers early germanic lock so I was working with the best components.  But I really don't think the white lightning needs to be drilled out any.
Do try the gonne to see how it shoots before messing up the liner.
volatpluvia

[T*O*F]

Blah, blah, blah......more bench racing where everyone gives their own private formula.  Of course, for some unknown reason they have to include the caliber, whose barrel, whose liner, patch thickness, load, and a bunch of other things that are not germaine to the question asked.

Sizing your touch hole is dependent on the granulation of powder you will be using.  The screen sizings of powder granulations is no secret,  The hole should be sized slightly less than the granulation of powder you will be using.  When it starts to self prime, you replace the liner.

Obviously, military muskets or larger guns were designed to use 1F powder and they necessarily have a larger hole than a .36 cal squirrel rifle using 3F powder.  A fowling gun or shotgun might use 2F for its load and would have a hole between the above two.

[David Rase]

Blah, blah, blah......more bench racing where everyone gives their own private formula.  Of course, for some unknown reason they have to include the caliber, whose barrel, whose liner, patch thickness, load, and a bunch of other things that are not germaine to the question asked.

Sizing your touch hole is dependent on the granulation of powder you will be using.  The screen sizings of powder granulations is no secret,  The hole should be sized slightly less than the granulation of powder you will be using.  When it starts to self prime, you replace the liner.

Obviously, military muskets or larger guns were designed to use 1F powder and they necessarily have a larger hole than a .36 cal squirrel rifle using 3F powder.  A fowling gun or shotgun might use 2F for its load and would have a hole between the above two.

TOF,
If the screen sizings are no secret then what size drill do you use for each granulation?
Dave

[Dphariss]

Blah, blah, blah......more bench racing where everyone gives their own private formula.  Of course, for some unknown reason they have to include the caliber, whose barrel, whose liner, patch thickness, load, and a bunch of other things that are not germaine to the question asked.

Sizing your touch hole is dependent on the granulation of powder you will be using.  The screen sizings of powder granulations is no secret,  The hole should be sized slightly less than the granulation of powder you will be using.  When it starts to self prime, you replace the liner.

Obviously, military muskets or larger guns were designed to use 1F powder and they necessarily have a larger hole than a .36 cal squirrel rifle using 3F powder.  A fowling gun or shotgun might use 2F for its load and would have a hole between the above two.

One that will not pass FFF swiss is going to be pretty small since as I stated 1/16 will  pass some FF.
With a liner like a WL the powder granulation is irrelevant.
If no liner is used then it a 3/32 is pretty well a necessity at least based on my experience.
Swiss apparently uses a .020 minimum and a .034 max screen size for FFF. This is before  polishing.
Dan

[Acer Saccharum]

Somebody's cranky today. 

[David Rase]

Somebody's cranky today. 

And your point Tom? 

[A.Merrill]

    Dave R,     I started putting a crown on my liners back in the 70's and I always thought it helped speed things up by funneling more flash into the barrel . I just use a countersink tool to crown it with.    AL
      

[Dphariss]

   Dave R,     I started putting a crown on my liners back in the 70's and I always thought it helped speed things up by funneling more flash into the barrel . I just use a countersink tool to crown it with.    AL
      

To continue the discussion somewhat.
I have a swivel breech with a flat face liner in one barrel and a similar one with a small but significant countersink in the other barrel. If there is a difference in any form I cannot tell it. Now, if I were forced to give and "opinion" or choose I will choose the flat faced. I believe in a fouled situation that the countersunk version is more likely to have a layer of fouling in the countersink and thus promote misfires since I have experienced this, but not SFAIK with the swivel breech.
We also have to remember that very little or no flash enters the vent. The ignition (IMO) is from radiant heat. Since the bore is sealed it would require significant pressure to blow fire into the vent any significant distance. Though on rare occasion a spark may bounce in or a grain of flaming priming might enter the vent most the heat source is radiant. Again this is my opinion. So in theory the main charge is actually father from the pan (by some minute distance) in the counter sunk vent. The closer the main charge is to the prime the more reliable and fast the ignition (the reason for the recessed Manton locks).

I also favor the flat faced because this was the standard with Manton and other late English makers. The only people I know of, outside maybe Larry Pletcher who has done a lot of testing, that actually spent time trying the REALLY improve the FL. They were doing it for fame and MONEY. I would also submit that there has been no real advancement since the late 1810s. So if we look there we will likely find the answers.
Though some of their answers are not appropriate for 18th century rifles.

Dan

[Larry Pletcher]

Hi Dan,
I also think the jury is still out on the best surface opening configuration for the vent.  There is a fluid dynamics theory that suggests that a funnel shape may be better - constant velocity stack on Stromberg 2 barrels as an example. 

I hope to have a way to explore this with help from Tom Snyder.  When I bought Tom's vent tools, he made me a tool to cut a funnel shaped opening on the barrel surface.  This will be used on a gun that is being built now.  Steve Chapman and I  intend to cut the the vent hole using Tom's tools and time the vent, add the exterior funnel, and time again.  (As you can imagine, with the very thin web, the funnel will be quite small.)

As with many experiments, there may be no significant difference.  But, one never knows without running the test. Currently I like a CLEAN vent with barrel powder visible  through the hole and prime against the barrel flat.  I believe that loaded this way, we are igniting one charge instead to two separate ones.  If a shooter can't or won't keep the vent clean, all this is out the window. IMHO,
Regards,
Pletch

[dannybb55]

It has always struck me as a deviation from traditional practice to put any liner on a FL. One look at a rifles breech and "Oh look, a liner, it's new!" We want to hunt and shoot so traditional and then we go late english and bush the vent. My Deringer Indian Rifle is not getting one, and I am using a post drill to run the hole in.

[Curt Larsen]

Sort of sounds like we're in a rut.  Just to change to something else, has anyone tried one of Tom Snyder's counterbores?  They require a 1/16" pilot hole for mounting the counterbore on the inside of the barrel.  I know they are a bit harder to install than a WL liner but just wondered.
Curt

[Larry Pletcher]

Sort of sounds like we're in a rut.  Just to change to something else, has anyone tried one of Tom Snyder's counterbores?  They require a 1/16" pilot hole for mounting the counterbore on the inside of the barrel.  I know they are a bit harder to install than a WL liner but just wondered.
Curt

Curt,
Tom Snyder's tool is the basis for the experimentn I mentioned above.  I have an Dickert rifle built by Mike Miller; Mike used Snyder's tool. The gun works fine; I have confidence this method.

My only reason for this test is to find out what we can learn. My  only thing is adding to our knowledge.  I have guns that I really like using both methods of ignition.

regards,
pletch