Touch hole location

[Uncle Alvah]

I have everything I need, I believe, to start my first build. I had the barrel channel cut and the stock pre-carved by Jack's Mountain.
I am working from  the "Re-creating the American Longrifle" book. The barrel is fully seated in the channel and the breech face flat against the end of the channel.
I want to inlet the pan bolster but first the location of the touch hole must be determined first yes?  Aside from the process described in the book, any hints tips or advice on locating/marking the TH would be appreciated.

[rich pierce]

Using a ramrod determine where the face of the breechplug is. If you are using a vent liner obviously the rear edge of the liner must be in front of the front edge of the breechplug. And the top and bottom of the liner must locate well on the side flat. Outside of that, keep the touch hole in front of the plug and vertically, where you want the lock positioned.

[Acer Saccharum]

Are you going to use a liner? White Lightnin or other?

if yes, and the liner threads are 1/4" diameter, then the touch hole should be 1/8" ahead of the breech plug. If the barrel flat is 3/8" wide, you have a little vertical play, before the liner flange runs into the corner of the barrel flat.

The hole in relation to the pan should be centered front to back on the pan. The hole can be as low as just above the bottom of the pan valley, and as high as centered on the top surface of the pan.

Realize that the lock can be rotated around the touch hole, which gives you a little freedom in front retaining screw location. You also can rotate the lock a little to get ideal wrist/lock design.

Always consider:
1) lock bolt placement before getting over-committed (ie: removing wood that shouldn't have been removed).
2) type of trigger, placement, and the impact on the wrist wrist profile.

This is probably the most critical part of any gun build. So take your time and ask questions.

[PPatch]

I hope you plan to use a touch hole liner, preferably one of Jim Chambers White Lightings, Ignition will be more reliable and faster with a liner. The 1/4 inch one will be fine. I don't know what barrel you have (what do you have?) but the breech face on the majority of modern barrels is exactly 1/2 inch forward of the rear end of the barrel. With a Chambers 1/4 inch liner the touch hole should be an eighth inch in front of the breech plug face and centered on the flat, or slightly above center. In other words, 5/8ths forward of the rear of the barrel, but not knowing what barrel you have that might not be true.

Your lock and trigger locations all key off the touch hole, which will then determine where your trigger guard goes, so be extra extra careful of its placement.

dave

[bama]

Has the lock been pre inlet? If so where is it's location in relation to the face of the breech plug? Many of today's precarved stocks have the locks inlet with the lock forward enough to allow the use of a vent liner that will allow the threads of the liner to line up with the face of the breech plug. If so this pushes the fence of the lock forward toward the muzzle and it will not line up with the back end of the barrel. This is not a problem but some people have to have the fence lined up the the end of the barrel. I think that Jim Chamber's kits have the locks in let so that the fence does line up with the back end of the barrel. If your lock is inlet like this then you will have to notch the face of the breech plug to install a vent liner. Last if your lock is not inlet then you can make the choice of where to install the vent liner which in turn locates your lock. I hope this make sense.

[Uncle Alvah]

I hope you plan to use a touch hole liner, preferably one of Jim Chambers

I do but I don't have it yet. Sending for it tomorrow.

I don't know what barrel you have (what do you have?)

44" .36 Colrain Swamped.

[PPatch]

Okay then. Jim Chambers sends installation instructions with the White Lighting liner, you'll need a proper sized drill bit and tap to get it in. Be careful not to install too deep as you do not want it intruding into the firing chamber, but (ideally), flush with the inside of the barrel wall. You don't necessarily need to install it right away, but do mark the barrel where it will go. I usually just put an indent as a marker.

The Colerain barrel ought to have a 1/2 inch long breech plug, measure the depth of the barrel with a ramrod or something like it and lay it alongside the barrel to check. Another method, and recommended, is to remove the breech plug so you can check that it is installed correctly, I do this with every build, removing it also gives you an opportunity to polish the plug face to a mirror finish which aids with cleaning.



 Have all the fun you can.

dp

[Uncle Alvah]

http://i.imgur.com/ThhXEos.jpg

The flat, IIRC, is .4.
If I use a 1/4" WL touchole, with the pan positioned correctly, is it true that the top edge of the bolster should NOT protrude above the top edge of the barrel channel wood as it is in the picture?

[WKevinD]

You have something wrong going on there. If Mark (Jacks Mountain) inlet the barrel it will rest fully in the inlet. yours needs to  drop in at least untill the top flat is even with or slightly below the wood. I'd recomend inletting the barrel tang first, locating the web between the barrel and the ramrod hole (front lock bolt location), mark the front of the breech face on the lockside barrel flat then inlet the lock and that will allow the center of the liner to be located.
There are probably other/ better ways but that is the order I use.
Kevin

[PPatch]

Two things - one; In your picture the barrel isn't seated deep enough, it needs to be seated downward in its final resting place, and setting level, before you can determine where that bolster and pan will go in relation to the touch hole. Two - clean off that barrel flat (light sandpaper) and mark where the tough hole will go, a thin point black marker will do, spray it with hairspray, or clear lacquer, to keep it from smearing. Once you've done that proceed to position your lock.

Regards the upper edge of the wood and bolster; the tops should be level with one another, BUT, at this point you may have some wood to remove off the upper edge (I don't know). You determine if you still have wood to remove by seating the barrel and observing where the wood is on your flat, if the barrel is all the way down and the wood goes up past halfway on the flat then take some wood off all along the upper stock until you have half the flat showing all the way to the muzzle.

1. Clean barrel flat - mark where the touch hole will be.
2. Seat the barrel all the way - is the wood showing half the flat, or perhaps a bit more? Good.
3. Using the touch hole location as the focal point play with the lock until it is orientated on the stock to your satisfaction.
    - Be sure you have the nose of the lock positioned so that your front lock bolt goes through the web between the barrel and ramrod - if there will be no front lock bolt then you have a bit of freedom orienting the lock as I remark below.
    - pay attention to where your sear bar is as that will dictate where the triggers go - this is important.
    - The tail of the lock should be fairly centered on the wrist, slightly higher is better than lower - fiddle with it and get it as close as you can.

After that you know where that bolster goes and can inlet it.



4. Take a break.

dave

[Uncle Alvah]

Carelessness on my part. I had dropped the barrel in to help protect the stock and blunt warpage. Because of circumstances beyond my control, this project has been on the bench for about 5 months.

[Acer Saccharum]

As to the pan edge above or below the line of the stock, I have seen(and made) guns with locks higher than the wood. 

There are few "true" things in gun building. The longrifle is such an enigmatic and elusive beast, hard to define by 'the right way'.

But your question about touchhole location is central to the design of the gun. I see your photo holding the pan, separate from the plate. This is ok, but do not locate the pan without knowing where the plate goes, how it's tipped, does it visually flow with the wrist, is there room for the lock bolts and ramrod, and and and is there enough wood under the tail of the lock for your trigger(s)? All that has to be decided BEFORE you inlet the pan.

[PPatch]

Where is your touch hole indication?

In this last picture either the barrel is canted a bit to the right, or the wood at the top, behind barrel, isn't square with the right side of your stock. Take a square and determine which it is, barrel or stock not square?

During the build keep your wood square (to the right side) and maintain centerlines as long as you can. If you've not marked out centerlines on the stock, top and bottom, do it now. You will find the lines very useful during the build. Of course they will eventually be removed late in the build.



Even though that barrel looks canted in your last photo, it looks like it is sitting down where it needs to be. Once you mark where your touch hole will be you are ready to inlet that lock, at least the bolster and the lock plate. Remember to determine where the sear bar will be once you have oriented your lock plate on the stock. I mark the top side of the lock plate to indicate where the sear bar is, disassemble the lock, and then put a mark on the wood underneath the mark I made on the plate. In fact I drill a 1/16th hole where that sear bar is so I can keep track of it as i inlet the lock guts (see pix below - a different type of lock but you can see the one-sixteenth inch hole). Once you know where that sear bar is you will then know where your triggers go.



dave

[flehto]

Working from a blank and using a 1/4dia. liner, I draw a vertical line 5/32" {.156} from the plug face. Usually the threaded plug length is .5  plus the  .156"  equals .656  which is the dim from the end of the bbl and the dim. used for the vertical line.  . I don't draw in the horizontal line before inletting the lock.

The lock is positioned so the front lock bolt doesn't interfere w/  the RR hole  and the "tail" of the lockplate is centered w/ the wrist. However high the top of the pan comes out isn't that important ...just so that the liner is on the side bbl flat.

Shown is a Bucks county LR w/ a high TH and also the top of the pan is quite a bit above the bbl CL and  is quite a bit above the forestock wood which is below the bore centerline by quite a bit.  The liner just makes it on the bbl flat......Fred

[Uncle Alvah]

[

Where is your touch hole indication?

Centerpunch mark

In this last picture either the barrel is canted a bit to the right, or the wood at the top, behind barrel, isn't square with the right side of your stock. Take a square and determine which it is, barrel or stock not square?[/quote]

[Uncle Alvah]

Sincer the top flat of the barrel  is square to the right side of the stock, is it necessary to shape the wood to remove the cant before inletting the breechplug and tang or should inlet the plug and tang and worry about the cant when shaping the stock later on?

[PPatch]

Worry about the slant later, go ahead with the tang inlet. Once you inlet your bolster/lock plate and begin shaping the top behind the barrel you'll know how to deal with the wood in that area behind the pan, as some of it touches the rear of your pan.



Also check out Flehto's picture above and you'll see how it will look.

dave

 

[Ric27]

Alvah, doing the layout work that you will find in chapter 13 of you reference book in where you must start. you didn't mention if you had shaped and inlet your tang yet. That is to be done before you get into this bit about the touch hole placement. After you have done the layout and located your breach face, the bottom of the barrel and the top of the ramrod channel you will have the necessary reference points to properly locate your touch hole and the lock around it. There will at times be a need for fudging but starting out you are seeking the optimum of course. Read your book and do the procedures in order. The book you have is very good but fairly academic in nature. So be patient and read all it has to say and then go back and do each step as it is laid out there in the book and you will get it right. Good luck.
ric