Touch hole height

[Wingshot]

Need some opinions on just how high above the pan bolster is too high for a touch hole liner. I have an older DGW .32 cal Mountain Rifle that’s a cap lock. I recently bought a DGW flintlock off a member here and I’ve finally got around to hopefully converting it over. I removed the cap lock, drum and have a liner that will work for that barrel. I can see that there’s going to be some additional inletting required to properly fit the lock plate into the mortise and it’s apparent that the top of the pan is not going to be level with the vent hole and is in fact slightly above it. Suggestions?

[rich pierce]

I’m not sure whether you’re saying the touch hole is going to be high or low. If the pan cover of the frizzen covers the touch hole it’s not too high. I don’t like low touch holes because I hunt and shoot in wet conditions. A little humidity-induced mucky fowling can block a touch hole near the bottom of the pan.

[Wingshot]

I’m going to check it with the frizzen mounted tomorrow, I’ll take some pictures as well. I’m kind of hoping there’s another member or two that’s gone through this conversion and experienced the same issue. The barrel being much a small bore the tapped hole for the original drum consumes the entire flat.

[Lone Wolf]

https://www.blackpowdermag.com/part-6-high-and-low-vent-experiments/

[Wingshot]

A very interesting experiment Lone Wolf, gives me a little more confidence. My (overly?) cautious approach to this conversion is that I remove the little wood I need to get the lock in properly only to find out ignition is lacking, then having a sloppy looking fit if I’m stuck going back to caps. Thanks for sharing that.

[Bill in Md]

It should be high enough to fully load the pan with powder...Higher is better!

[bama]

File the lock plate to fit the existing lock mortise.

[Steeltrap]

File the lock plate to fit the existing lock mortise.

Great suggestion.

How about making a new plug for the barrel and then drilling the vent where you want it?

[Wingshot]

File the lock plate to fit the existing lock mortise.

That’s another great idea and although I have not logged a bunch of time looking it over it may well  be the smarter play to file a little. The area that seems to need attention is the top of the plate behind the pan. Some careful filing and fitting might just save my bacon. Appreciate everyone’s help!

[rich pierce]

File the lock plate to fit the existing lock mortise.

That’s another great idea and although I have not logged a bunch of time looking it over it may well  be the smarter play to file a little. The area that seems to need attention is the top of the plate behind the pan. Some careful filing and fitting might just save my bacon. Appreciate everyone’s help!

With a flintlock that area behind the fence of the pan stops the cock. Filing it down could stick the flint into the pan. A work-around is to add to the shoulder on the cock, that stops against the top of the lock plate.

[Wingshot]

Just to follow up, I managed to fit the new lock into the mortise with some careful filing of the plate on the top arch(behind the cock) and a little wood inletting since the main spring was a bit beefier than the percussion lock. Took my time and had to remove a thin amount of the lock molding for the cock travel, triggers working good and that old Italian made DGW flinter throws some nice sparks! Touch hole is high but I feel it’ll be fine. I may try to get a few shots in this weekend. Thanks for the suggestions and as always, the encouragement!

[rich pierce]

Sounds good; enjoy shooting!

[Wingshot]

Only had time for a little plinking in the backyard today. 6 out of 6 shots all without a hitch. About a half pan of 4f, wiped the pan and picked the touch hole between shots. Surprisingly quick lock time from that Italian made DGW lock.

[Top Jaw]

I had one rifle that had a very high touch hole.  So high, it was barely covered by the side of the frizzen when closed.  I was a little concerned at first.  However I never noticed a reliability issue - or any perceived speed difference because of it.  If anything, that gun seemed “faster” than my others with a sunset TH location - at least in my mind. 😀  The priming is “flashing” upon receiving spark after all.  And therefore high is seems better than too low (maybe not because of the alleged physics involved) but definitely with potential increased fouling - at least to my mind.  Especially if low in the pan and shooting on a humid day.  So anyway, that’s my story, and I’m sticking to it.  ✅

[Scota4570]

The location is fine.  It is slightly above the top of the lock-plate, not much.  The frizzen fully covers it when closed. 

Hint, if a picture is to show some detail, maybe spend some time cleaning it up or trying again.  The picture should communicate the intended information as posted. 

One theory on how the pan lights the main charge is that it happens by radiant heat.  I locate my touch hole in the classics sunset position.  I prime with a tiny amount of 4F and jostle the rifle to coat the bottom of the pan in a thin layer.  When the powder goes off the fireball has no direct fuse to the vent.  I get the same reliability with flint and percussion gun. 

[JTR]

I remember when Pletch was doing those tests, and his careful approach took all the hocus-pocus out, and left no doubt as to what was what.
John

[Jim Kibler]

I remember when Pletch was doing those tests, and his careful approach took all the hocus-pocus out, and left no doubt as to what was what.
John

Funny thing is, none of this has mattered to many folks.

[Daryl]

I had a .32 that had a VERY high vent hole. The ignition reliability was terrible. We meaning Taylor, made a new vent plug with an angled vent hole to the bottom of the plug, hollowed out as could
be on the inside. Ignition was wonderful after that. The exit hole was then at the sunset position.

[Darkhorse]

After shooting one day I took some photos of the rifle I was using. Notice from the gray fouling on the barrel and lock that it appears the flash goes up and out. My TH's are all at the sunset position perhaps they could be a little higher for fastest ignition?

[whetrock]

Hey Darkhorse,
If that Siler is giving good ignition, then it seems to me that you don't have any real problem. But I see what you are saying about that being a lot of fouling. How much priming powder are you using? It looks like you may be using more than you need. You don't need to fill the pan. It just needs a pinch in the bottom. You might experiment a little and see how little you can use and still get reliable ignition.

By the way, you wouldn't need to waste lead to do that. A light load of powder and a tight paper wad would be fine. But in general, if the pan goes off, the main charge will go off.

Very nice looking rifle, by the way.

[smylee grouch]

Do any of you shooters think or suspect that the " WEB " of the vent liner might be too thick for reliable ignition ?    

[Daryl]

The thicker the web, the slower the ignition and the larger the vent has to be, imho.

[Wingshot]

My pic does kind of stink, I snapped after the shooting session and the flash fouling hid the liner very well, lol. If the shooting test I preformed (albeit brief) my plan was to make a new liner and drill on a slight angle as was mentioned above. Warmer weather will have me putting it through its paces, maybe even a squirrel hunt this weekend since the weatherman says we’re going to warm up to almost freezing!!

[Darkhorse]

Whetrock, Those photos were taken years ago before I had settled on my prime charge and could have been shot with a full pan. I now use one push, perhaps 1 1/2 grains, on a pan charger and get excellent results. I posted that photo to demonstrate to the OP where the flash goes and in what range the TH can be in.
That Siler works perfectly. It took awhile to get it tuned to my satisfaction but I finally got it dialed in. Now both my Silers are tuned identical. Prime ignition and main charge almost sound like one. Very fast and smooth. Of course there is more to it than just the lock, touch hole geometry and placement plays a major part also. Years ago I made TH liners for myself and others and I learned a lot about what works good and what doesn't. Now I just use white lightnings because they just work well.