Transfer holes from lock plate to as-cast plate

[ShutEyeHunter]

This has me stumped & I couldn't find anything with search

I want to transfer the holes in an original lock plate to a replacement “as cast” plate. The darn as-cast plate doesn’t have the holes spotted. The bolster won’t let the two plates lie flat against each other. So (I think) I can’t just use a transfer punch

Any ideas from the experts?

[Metalshaper]

clamp together and use a set of transfer punches, that fit the holes and mark the spots?

Respect Always
Metalshaper/Jonathan

[Tim Crosby]

 A question if you don't mind; What are you trying to do, use old internals on a new plate?

    Tim C.

[rich pierce]

Use a piece of cardboard like from a cereal box and lay the old plate on it. Trace the lock. Pin prick the holes. See how it lines up on the other plate.

[ShutEyeHunter]

Yes, I messed up the cast in logo engraving on a Goulcher lock and I want to make a new plate and use the old internals

I was thinking I couldn't use a transfer punch because the bolster won’t let me get the old plate flat on top of the new casting. Old lock works fine, so I didn’t want to file off the bolster. Will a transfer punch stay straight enough to mark a hole that’s 1/4” away?

As I’m typing this, I’m thinking if I clamp the parts together I could use my drill press to hold the transfer punch perpendicular?  With layout dye, doesnt take much pressure to mark it

[ShutEyeHunter]

Use a piece of cardboard like from a cereal box and lay the old plate on it. Trace the lock. Pin prick the holes. See how it lines up on the other plate.

That was my first thought, but I was worried (as usual) that I couldn’t get the holes precise enough for the bridle. What kind of tolerance do I need?

[rich pierce]

Use a piece of cardboard like from a cereal box and lay the old plate on it. Trace the lock. Pin prick the holes. See how it lines up on the other plate.

That was my first thought, but I was worried (as usual) that I couldn’t get the holes precise enough for the bridle. What kind of tolerance do I need?

You can clamp the bridle on the exterior of the plate once you have a pretty close location from the template.

[Clark Badgett]

Yes, I messed up the cast in logo engraving on a Goulcher lock and I want to make a new plate and use the old internals

I was thinking I couldn't use a transfer punch because the bolster won’t let me get the old plate flat on top of the new casting. Old lock works fine, so I didn’t want to file off the bolster. Will a transfer punch stay straight enough to mark a hole that’s 1/4” away?

As I’m typing this, I’m thinking if I clamp the parts together I could use my drill press to hold the transfer punch perpendicular?  With layout dye, doesnt take much pressure to mark it

Get a couple pieces of 3/8” key stock and place them between the plates. Line everything up perfectly, clamp together and use transfer punches to spot new holes. Make sure to place the risers where there aren’t any holes.

[Scota4570]

I can easily mess this up so I am extra cautious.  I do one hole at a time.  First the tumbler hole.  I'd use spacers and a transfer punch.  Next the bridle screw hole.  That is determined by where it needs to be to function smoothly, I transfer it through the bridle screw hole with a transfer punch.  I then drill and tap it.  I then secure it with the screw and transfer punch the sear screw pivot hole.  Drill and tap it.  The sear spring screw location and the mainspring pivot can be transferred from the old plate.

If I was making a plate I'd leave it thick super glue them together to transfer the hole locations.  The boss is can be added later by silver solder of thinning  the plate on a milling machine.   

[ShutEyeHunter]

 This is starting to make sense, thanks!  So I locate (bore) the tumbler hole and then use bridle itself to spot its holes! Mainspring peg can (probably) be spotted with the template or 3/8 key stock & transfer punch methods

[Clint]

Locate and drill the tumbler hole just big enough to admit the support pin that goes into the bridle.Use that hole to temporarily mount the bridal on the outside of the lock plate. Add the flint cock to the tumbler and rotate to the 'down' or fired position and mark the plate (trace the tumbler) Let the bridal rotate as close as you can to match up with the 'down' position and mark the plate fro the sear and bridle screws. Double check the hole locations with the old lock plate and drill ONE of the bridal screws. Tap the hole and screw the bridal to the plate, then drill the other hole. If you drill both holes, you may get into trouble. Now you can ream the tumbler hole and assemble the package.

[Birddog6]

Last time I had to make a lock plate, I took two short pieces of 5/16" key stock & put between the plates, lined them up & glued with Devcon 2000 clear epoxy. Let it set overnight & then went to drill press & drilled thru the old plate into the new one & everything worked out fine. 
As long as you have very sharp bits & start with light pressure so the bit doesn't wander.  I also put the drill bit up in the chuck very far & just leave enough bit to drill the hole. That leaves less bit length to flex.