Lock geometry question....

[GANGGREEN]

This photo is a bit misleading because I had to take it at a downward angle so that you could see the touchhole. I'm using a re-purposed barrel with the touchhole already drilled. When I lined up the L&R late English lock to start inletting the lock mortise, I see that it doesn't really line up right (again, the photo looks OK but it's misleading). If I put the nose of the lockplate between the barrel and ramrod channel, the tail sits way to low and if I sit the tail halfway on the wrist, the nose sits too low. Also, the touchhole is apparently going to have to sit inside the pan, lower than flush/horizon level. Now, I suppose that I can drill a new hole slightly higher and install a liner, but that's still not going to totally rectify things.

What am I doing wrong? Am I missing something obvious? As it is, I THINK I'll be able to make this work, but only by adding a liner and moving the touchhole slightly up and by drilling the nose of the lockplate very high. Thoughts?

 

[dlgraley]

No problem at all drilling the nose of the lockplate high; does not have to be centered.

 

[vulture]

I am assuming that you are talking about the front lock bolt when you talk about drilling the nose of the lock plate, but what is the possibility of using only one lock bolt, the center one. I've see cap locks installed this way, can a flintlock be installed this way also. If so then no hole in the nose of the lock plate would eliminate the problem altogether.

 

[GANGGREEN]

I am assuming that you are talking about the front lock bolt when you talk about drilling the nose of the lock plate, but what is the possibility of using only one lock bolt, the center one. I've see cap locks installed this way, can a flintlock be installed this way also. If so then no hole in the nose of the lock plate would eliminate the problem altogether.

I didn't think about that. Does anyone think it's a reasonable alternative/solution? I've been driving around all day thinking about it and I'm wondering if I might not be better off using a Germanic style of lock. I'll take one off one of my other rifles and see if things line up better.

 

[Vaino]

The problem is caused by the bottom wrist contour being cut too soon....not enough wood. If the front lock bolt hole is high in the lock nose....no problem. The problem you have is w/ the position of the bottom of the lock tail.

Perhaps some of the lockplate tail could be filed off and a new, higher TH would solve the problem? A 1/16" higher lock nose and the front lockbolt hole is in....use a #6-32.
Good luck.....Fred

 

[GANGGREEN]

The problem is caused by the bottom wrist contour being cut too soon....not enough wood. If the front lock bolt hole is high in the lock nose....no problem. The problem you have is w/ the position of the bottom of the lock tail.

Perhaps some of the lockplate tail could be filed off and a new, higher TH would solve the problem? A 1/16" higher lock nose and the front lockbolt hole is in....use a #6-32.
Good luck.....Fred

I thought that about filing some away on the lower rear. I also happen to have a #6-32 lock bolt which would be used up front. Thanks for your thoughts Fred.

 

[GANGGREEN]

Also, if I drill for the front lock bolt roughly where the lockplate is sitting in this photo, I'll not only have to drill high but back a bit. It will be above the mainspring, there's nothing else in there to get in the way if I drilled it a bit further back than normal, right?

 

[Zonie]

There is nothing that says the front lockbolt must be centered with respect to the shape of the locks forend. In fact, it is rare that the front lock bolt will actually be in the middle of that area of the lockplate.

Getting back to the location of the touch hole.

Move the lockplate around to get the touch hole as close to the right place (centered with the pan and even with the surface of the top of the pan.) as possible.

You may need to compromise a bit on the location but that relationship between the touch hole and the pan should be the main driver.

After the lockplate is installed, you may have to modify the shape and size of the wooden lock panel but IMO, that's the nature of the game.

The barrel vent liner tells the lock where it has to live. The lock tells the trigger where it has to be and what the lock panel shape is going to be. The trigger tells the butt plate and trigger guard where it has to be and so forth....

 

[Artificer]

First off, :hatsoff: to Fred for his suggestions!

GangGreen,

A simple way to see how much you can move the front lock screw hole back and ease your concerns ahead of time is to put a piece of tablet paper on the inside of the lock. Punch it with a hole punch if you can for the mainspring post/stud hole, though just piercing the paper would most likely work. Tighten the mainspring in a mainspring vise and put it on the paper and up tight against the lockplate. Use a pencil and FIRMLY press down and trace around the top and front of the mainspring. Also trace around the outer surface of the lock plate and especially the bottom and front of the lockplate ”“ this to align the paper pattern/template later on. Take the mainspring off the lock and trim around the line on the front and bottom of the lockplate. Now put the paper tracing/template on the front of the lockplate and align it with the hole and lockplate front and bottom. The lead pencil tracing should show you where the mainspring will sit and how far back you can drill for the lock plate screw hole. You may find it helpful to trim the tracing/template along the line that outlines the top and front of the mainspring.

Gus

 

[Artificer]

P.S. Looking at the photo in the link (Click the "View 2" tab) and where the mainspring sits, it seems you have room to move the lockplate screw hole further back.
http://www.trackofthewolf.com/Categories/PartDetail.aspx/724/1/LOCK-LR-900-D

Gus

 

[GANGGREEN]

Yeah, since the forward lock bolt will apparently have to be on the top edge of the lockplate, it looks like it can be moved back quite a bit and still clear the mainspring. Thanks for that link and suggestion.

 

[Artificer]

Fred and Zonie deserve high praise or their suggestions, but I am pleased you may find some use for my suggestion.

Gus

 

[GANGGREEN]

Fred and Zonie deserve high praise or their suggestions, but I am pleased you may find some use for my suggestion.

Gus

Yes, thanks to Zonie, Fred and all for their help. I'm still not sure what I'm going to do yet, I'll need to sit and study it a bit more.

 

[Pete G]

That lock is a late flint period lock and by then a single lock bolt was fairly common. You could also install a lug that slips under the head of a screw in the front of the lock mortise. Sidelock shotguns are a good place to look for inspiration for this arrangement.

Also, if the vent is too low you can deepen the pan to help alleviate the problem. It's not optimum, but is considerably better than a vent at the bottom of the pan.

 

[GANGGREEN]

Thanks Pete. I think between several things I'll be fine with the vent placement. The first thing I'm going to do is to install a vent liner and try to get the vent hole up a little bit, then I'll figure out lock placement and bolt arrangement.

 

[EC121]

Check to see how much metal there is in the bottom of the pan and grind it out some. 1/16" will make difference. I use one lock bolt all the time. Mostly due to laziness, but it works fine. I also harden the edges of the lock inlet with epoxy or Gorilla Glue to prevent splitting, and I harden the wood screw holes with CA glue. Be careful if you try to drill the touch hole out. A regular bit will run on you. It really requires an end mill bit to prevent runout.

 

[GANGGREEN]

Check to see how much metal there is in the bottom of the pan and grind it out some. 1/16" will make difference. I use one lock bolt all the time. Mostly due to laziness, but it works fine. I also harden the edges of the lock inlet with epoxy or Gorilla Glue to prevent splitting, and I harden the wood screw holes with CA glue. Be careful if you try to drill the touch hole out. A regular bit will run on you. It really requires an end mill bit to prevent runout.

Yeah, I was worried about a drill bit getting happy feet. I don't know that I have an end mill bit for metal and in the proper size, maybe I'll have to look into purchasing one today. Thanks.

 

[Vaino]

An end mill must be used in a vertical milling machine because it has a very stable spindle and the workpiece must be clamped so it doesn't move. A drill press spindle isn't stable enough and I wouldn't chance it even when the workpiece is clamped......Fred

 

[Artificer]

Probably the best way to accurately align the location of the hole is to scribe or center punch the location and then use a spotting drill bit before drilling the hole all the way through. You will need to know what size hole you want to drill, of course, and get the spotting drill bit that is that size or the size smaller than the drill bit you intend to use.

Here is a drill bit size chart: http://www.gearhob.com/eng/design/drill_eng.htm

You can scroll down through the sizes on the left to find the best size for the drill bit you want to use. http://www.mscdirect.com/browse/tn...ills?navid=12106130#navid=12106130+4287565637

Gus

BTW, if you have never used a spotting drill bit before, I would suggest practicing on a bit of scrap barrel or steel before using it on your barrel.

 

[GANGGREEN]

Thanks everyone. At present, I don't really think that there's anything wrong with the touch hole location so even if I do add a liner, I'll probably drill the hole centered on the present touch hole. I'm inclined to use a single bolt through the lock mortise; I'm going out now to work on it for a bit. I'll post photos or description when I decide and get it worked out.