Author Topic: Touchhole problem  (Read 10686 times)

Offline Elnathan

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Touchhole problem
« on: June 10, 2010, 05:05:23 AM »
Well, I seem to have made a major error. I am building a rifle with a .54 caliber barrel with a 1.080 breech and a Chambers Virginia lock. I inletted the lock some time back, have already partially shaped the lock panels, and was getting ready to inlet the trigger when I realized that the lock placement makes the touchhole placement very awkward indeed. If I use a 3/8" cone, the edge of the cone will be flush with the breechplug but rather high (not even quit touching the line across the top of the pan, much less in the sunset position it should be) and rather far back, about 1/16" from the center of the pan. I can grind back the pan slightly, but the touchhole will still behind the center of the pan. If move the touchhole further forward, I run the risk of creating a fouling trap. If I try to lower the touchhole, the cone will drop beneath the bore (and if I use a liner, it will drop below the barrel flat). If I use a smaller cone, I will create a fouling trap. I can't move the lock, as the panels have already been established, and I can't move the barrel.

Does anyone have any ideas? I have learned at least one lesson: when building a rifle to plans drawn up from Track of the Wolf pictures, don't follow them without double-checking to make sure the pieces actually fit together properly. The pan on the Virginia lock is not where it looks like it is in Track's photographs!
A man can never have too much red wine, too many books, or too much ammunition -  Rudyard Kipling

Offline Dr. Tim-Boone

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Re: Touchhole problem
« Reply #1 on: June 10, 2010, 05:18:56 AM »
Sounds like the barrel and lock are no longer movable??  So use a smaller 1/4 inch Whilte Lightning liner and place it with the hole centered on the pan where it is supposed to be. The "fouling trap will just have to be cleaned. Thats what breech scrapers are made for.... honestly my experience is that if the touchhole is a little forward of the plug it really doesn't hurt much....unless maybe you plan on shooting a couple hundred rounds between cleanings??  I think you would have to wipe the bore anyway.

just my $.02
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Offline Nate McKenzie

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Re: Touchhole problem
« Reply #2 on: June 10, 2010, 05:30:37 AM »
The touch hole does not need to be perfectly centered top to bottom on the barrel flat. Its relation to the pan is much more important. Like Tim said, move it forward a little bit and get it in the sunset position. A 1/4" liner might fit and look better.

Offline Long John

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Re: Touchhole problem
« Reply #3 on: June 10, 2010, 05:44:59 AM »
Put the vent in the ideal location from the perspective of the lock.  Don't worry about the so-called "fouling trap".  If you had a groove filed in the breech face you would have a trap.  But as long as the breech face is flat it is OK if the vent comes into the barrel a little forward of the breech face.

JMC

northmn

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Re: Touchhole problem
« Reply #4 on: June 10, 2010, 12:13:10 PM »
I can only agree with what is already said.  Touch hole placement to the pan is very important.  so much so that I have had to make liners to correct misplaced ones.

DP

Birddog6

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Re: Touchhole problem
« Reply #5 on: June 10, 2010, 01:08:53 PM »
I agree. Smaller vent liner & move it where it needs to be. I build all of mine with vent ahead of the breechface so the vent liner threads & breechplug threads don't intersect & I have had zero troubles with them.   ;)

J.D.

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Re: Touchhole problem
« Reply #6 on: June 10, 2010, 08:59:23 PM »
Just to play devils advocate, why install a liner at all..at least before the TH burns out?


God bless


Offline Acer Saccharum

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Re: Touchhole problem
« Reply #7 on: June 10, 2010, 09:23:40 PM »
Just to play devils advocate, why install a liner at all..at least before the TH burns out?


God bless



along these lines, I just got a set of inside coning tools from Tom Snyder (Snyder on the ALR). My current build I coned, but have no liner. Fantastic tool.

...and so what if the cone intersects the breech face a little? not a big deal. Like the others have said above, touchhole placement in relation to the lock is the most important constraint. All others are secondary.

Tom
Tom Curran's web site : http://monstermachineshop.net
Ramrod scrapers are all sold out.

Offline Dennis Glazener

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Re: Touchhole problem
« Reply #8 on: June 10, 2010, 09:48:40 PM »
Quote
Just to play devils advocate, why install a liner at all..at least before the TH burns out?
I agree on most thinner walled barrels but I have a .54 with the same diameter breech, Chambers Siler lock. It set the main charge off about 50% of the time until I installed a white lighting liner, have used them ever since. I had even opened the TH up to around .070 which helped a little but still was slow and fired only about 65% of the time. After the liner it very seldom flashes the pan without setting off the main charge.
Dennis
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Offline Elnathan

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Re: Touchhole problem
« Reply #9 on: June 10, 2010, 10:22:08 PM »
The problem is not that a cone, internal or liner, will interfere with the breechplug threads, but that the touchhole will be too far forward. If I use a 1/4" cone, it will leave a 1/8" gap between the rear edge of the cone and the face of the breechplug, which I am afraid will trap fouling and make it very difficult to clean. I was planning on using an internal cone if I could.

I have not been particularly happy with the way this rifle has been going for a while, and have toyed with the idea of starting over with a new piece of wood even before I discovered my layout error. On the other hand, it isn't completely bad as it is and I have a lot of work in it so far. I am trying to decide what to do...
A man can never have too much red wine, too many books, or too much ammunition -  Rudyard Kipling

Offline Acer Saccharum

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Re: Touchhole problem
« Reply #10 on: June 10, 2010, 10:55:51 PM »
Breech the barrel threads deeper, and get or make a plug with a longer threaded section.

Tom
Tom Curran's web site : http://monstermachineshop.net
Ramrod scrapers are all sold out.

Offline rich pierce

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Re: Touchhole problem
« Reply #11 on: June 10, 2010, 11:04:04 PM »
Lots of times I get discouraged on a build when something's not perfect, and then it turns out fine.  I don't think you should have trouble keeping it clean if you use tow on a worm.  Much better than patches on a jag in my experience.  Of course if it is very small bore and you're well toward the front of the charge, you may want a longer breechplug as suggested, but you'd better have a lathe or a machinist who really understands how you want threaded section of the breech  lengthened.
Andover, Vermont

Offline Dr. Tim-Boone

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Re: Touchhole problem
« Reply #12 on: June 10, 2010, 11:09:29 PM »
Many guns are designed with a cavity in the front of the plug or a patent breech.. even they can be cleaned. There is nothing magic about have the rear edge of your touch hole adjacent to the face of the BP....... It just doesn't really matter. It seems you are making this harder than it needs to be??
De Oppresso Liber
Marietta, GA

Liberty is the only thing you cannot have unless you are willing to give it to others. – William Allen White

Learning is not compulsory...........neither is survival! - W. Edwards Deming

Offline Nate McKenzie

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Re: Touchhole problem
« Reply #13 on: June 11, 2010, 12:18:56 AM »
Like Tim says.

Offline Elnathan

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Re: Touchhole problem
« Reply #14 on: June 11, 2010, 06:23:37 AM »
It seems you are making this harder than it needs to be??

Possibly. I do tend to get hyper about details sometimes. Thaks for the advice, everyone.
A man can never have too much red wine, too many books, or too much ammunition -  Rudyard Kipling

J.D.

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Re: Touchhole problem
« Reply #15 on: June 11, 2010, 08:23:53 AM »
The problem is not that a cone, internal or liner, will interfere with the breechplug threads, but that the touchhole will be too far forward. If I use a 1/4" cone, it will leave a 1/8" gap between the rear edge of the cone and the face of the breechplug, which I am afraid will trap fouling and make it very difficult to clean. I was planning on using an internal cone if I could.

If you're that worried about the relationship of the TH to breech face, would moving the barrel forward that 1/8", by inletting patch to the face of the stock, where it contacts the breech work for you?

IF you select the right piece of wood and inlet it carefully, the patch won't show once it's finished.

Don't know how moving the barrel forward that small distance would affect a swamp barrel inlet, but it might work...or not.

Just kinda thinkin'...typin' out loud, so to speak...type.

God bless

Offline bob in the woods

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Re: Touchhole problem
« Reply #16 on: June 11, 2010, 03:01:13 PM »
This may seem strange, however; here goes. I never want my TH to be in line with the plug face. I like 1/16 th in to 3/32 ahead of the face at least. When I used a liner, the back edge of the liner lined up with the face, not the TH.  I think having the TH itself in line with the breach face is looking for ignition trouble.
In my experience, the breach face is never that clean anyway, so I don't want that interfering with ignition.
We have one fellow with a .36 with this arrangement, and he has to scrape the breach face during a match, or he has trouble.
I'd continue on in your build and not worry about it.

msw

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Re: Touchhole problem
« Reply #17 on: June 12, 2010, 11:16:11 PM »
I think that Dr. Tim has it in one- let the location of the pan drive the train as regards the location of the touch hole.

just one guy's free advice, and probably worth every penny.

Offline Roger Fisher

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Re: Touchhole problem
« Reply #18 on: June 13, 2010, 01:34:24 AM »
Like Tim says.
Sure like Nate and Tim say!!

Gotta tell ya, your 'fears' of her being difficult to clean are unfounded.  Consider this:
After you arrive home from a shoot or the range take a cleaning patch and crunch it up on a patch worm (I have a seperate range rod already so fitted)  slop the patch good with water or your favorite bore cleaner and run this mess down in to the breech and let it sit while you nutz around with your other stuff 10 minutes or so.  The twist the rod around a little with a wiping motion against the breech. Withdraw it then do it again with another wet patch til the face of the patch comes clean. Then work at the bore as usual....  Going in with a patch on a jag just shoves all that $#@* down on top of the breech face.  Not good  Maybe thats been your problem.. An eight of an inch ahead of the breech no sweat. :)  Now you can sleep better at night. :D

jwh1947

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Re: Touchhole problem
« Reply #19 on: June 13, 2010, 05:06:59 PM »
Way to go, J.D.  A novel idea...make it look original.  You must be either a mechanical engineer or a rocket scientist.   ::)  Wayne

J.D.

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Re: Touchhole problem
« Reply #20 on: June 13, 2010, 07:32:25 PM »
Way to go, J.D.  A novel idea...make it look original.  You must be either a mechanical engineer or a rocket scientist.   ::)  Wayne

I'm not a rocket scientist or an engineer, but I did stay in a Holiday Inn Express the night I posted that suggestion.  ;D

God bless
« Last Edit: June 13, 2010, 07:37:25 PM by J.D. »

Offline Waksupi

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Re: Touchhole problem
« Reply #21 on: June 14, 2010, 08:23:20 AM »
If you don't own a breech face scraper, get one. Clean your gun properly.
 I firmly believe a liner should be placed so it just clears, or skims the breech plug when drilling and tapping. This will help direct the flash more into the charge, rather than at the tail end of it on the breech face. This will give more consistent, and faster ignition. If someone tells me they install a liner vent lined up right at the face of the breech, I think they either screwed up and don't want to admit it, or don't know any better. This is nearly impossible to clean properly.
Ric Carter
Somers, Montana

Offline sonny

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Re: Touchhole problem
« Reply #22 on: June 15, 2010, 04:02:43 AM »
Elnathan
when you install the smaller liner thru the barrel wall,the inside must always be taken down to be flush with the inside of the barrel.I know as you remove material off the touchhole liner you will get a smaller conned area on the inside of the liner.If you only have 1/8" to go to be perfect, you are all set.You can take the liner out after it fitting smoothly the barrel shape on the inside,an with  a small grinder ,re tapering the inside to be flared out  with a more wider cone to the breech face.Heck  you are all set!!!..........perfect.sonny