1 screw Lockplate

[Uncle Alvah]

How do you correctly position the hole for a one-screw lockplate?
Where should the lock bolt contact the lockplate?  I'm guessing drill/tap the plate for the bolt is SOP?

[FALout]

You really should buy one of these two books (or even both), "The Gunsmith Of Grenville County" by Alexander or "Recreating The American Longrifle" by Buchele (Shumway and Alexander).  If you really have an interest in building, these are the first things I have always pointed out for resource material as they give a great starting point. 

[SingleMalt]

How do you correctly position the hole for a one-screw lockplate?
Where should the lock bolt contact the lockplate?  I'm guessing drill/tap the plate for the bolt is SOP?

A "one screw lockplate" in my mind refers to a lock with only one screw showing behind the cock.  But, others use the term to mean the lock is held in the stock by one screw.  Which do you mean?

[Uncle Alvah]

I mean where the lock is held in by one screw.

[Uncle Alvah]

"Recreating The American Longrifle"   

Its on my bench....with a yellow high-lighter

[SingleMalt]

I mean where the lock is held in by one screw.

Through the stock, barrel tang lug, and into the lock bolster.  Position the screw so it misses the screw (if any) holding the bolster and pan to the lockplate.

[westbj2]

Alvah,

Remove the flint cock and using a magic marker or Dykem transpose the bolster area inside the lock to the outside surface and scribe it in.
Center punch and center drill the exact spot you want the drill to come out on the lock.  Be sure the barrel and stock are square to the vertical drill angle of your drill press or mill vise and clamp the stock in place.   

With the tap drill appropriate for the screw you intend use, drill thru the lock plate at the marked spot and right out the other side of the stock.  Put your tap in the chuck and start the tap gently by moving the belts of your machine by hand along with some slight down pressure on the quill.  When you have cut 2 threads or so remove the tap and finish the tapped hole with a conventional tap wrench. 

Remove the lock from its mortise and using a bit corresponding to the clearance size of your lock bolt, drill thru the previous hole and enlarge it to accept the lock bolt.
Jim

[PPatch]

Careful with this one - be very sure you are square and plumb when you drill the stock and lock plate. This operation is best done before any shaping of the lock panels. First, using the tap size bit you will punch and drill through the plate then on through the tang and stock - clamp a piece of wood on the off lock side to prevent splintering when the bit exits the stock wood. Use the clearance bit to slightly enlarge the hole in the stock and tang. Carefully tap the hole in the lock plate. You will have to trim off a lot of the lock bolt end so that it is almost flush with the lock plate. You then round it off to a dome shape and polish it.

In this picture you can see the polished end of the lock bolt peaking out from above the base of the cock.



dave

[Mike Brooks]

Isn't that one of the tumbler bridle screws?

[FALout]

UA, there really is only the two areas (a third for some styles).  The forward area for a front lock bolt , which you don't want and where the cock makes contact on the lock plate, the thick part,The thinner area below that would likey interfere with the mainspring. If you look at percussion rifles with one lock bolt, they are basically in the same spot as flint.  You have some room forward and back, but not much.  Your question on whether to drill and tap seemed odd.

On an Indians trade gun I copied, I put a third screw at the tail of the lockplate.  Now that one will make you puckerup, on that rifle there was no margin of error, no room to come forward due to sear arm.  Too close to either edge, there would have been distortion of lock plate edges when tapping threads.  Some day I'll post a pic.

[D. Taylor Sapergia]

Isn't that one of the tumbler bridle screws?

Yup!!

[D. Taylor Sapergia]

The rear screw (lock nail/bolt) is located in the rearmost, and lowest point in the plate bolster that still allows full threads.  This provides for as much wood as possible at a very delicate and fragile part of the stock.

[smylee grouch]

Some builders tapper the thickness of the lock bolster to flair out the front end of the lock as English guns and some Hawken style guns. It might be advantageous to do that (if you wanted that) before you drill and tap the lock bolt.

[PPatch]

Isn't that one of the tumbler bridle screws?

Yup!!

Yup, and now corrected. ;o)

dave