A sear-ious lock tuning

[rich pierce]

On a current build I chose a little-known and used commercial lock because the pan, frizzen, and frizzen spring matched my needs better than other, more popular models. 

This is not a product bashing thread and please don’t turn it that way if you reply.  I just wanted to show how to change sear arm position to a more favorable one.

You can see an unusually high sear bar position as delivered. This necessitates a very tall trigger blade and may confound leverage of a simple trigger for all I know. I didn’t like it.  So I made a new sear with more of an angle between the sear nose and sear arm.  Worked a charm.  Also learned that shortening the sear nose a tad changes thing quite a bit.

before fix




after fix

[Jim Kibler]

Nice fix, Rich.  I have no idea who made the lock, but I can't believe anyone would ever ship something in the condition it was.  How could someone think this to be ok? 

If the customer isn't experienced and able to identify this as a problem just think of the troubles something like this could cause.  Add this to the host of other problems that sometimes occur and you end up with a frustrated consumer who might not ever give black powder gunbuilding another try.

Jim

[jerrywh]

 I just want to point out another potential  problem. It is the form and position of the main spring. With the mainspring so high on the lock plate it will probably interfere with the barrel especially if the barrel is very large. Note the position of the mainspring on this English lock in the photo below. This prevents interference wit hthe barrel.

[rich pierce]

Good points, gentlemen.

Regarding design, I think or guess that some locks are copied off or based on originals that had their own issues. For example, previous versions of the Harpers Ferry 1803 lock were bad rock-busting bashers. Some of my best flint customers back in the day shot model 1803s. My flints were tough yet they needed a lot of them!

[E.vonAschwege]

Nice fix Rich!  Most locks need some work as shipped - Tolerances, screw fit, etc, though that sear placement is nuts.  Most locks on the market today use standard parts for many of their locks across the board and make them fit new lock designs, sometimes with less than stellar results.  I have a stash of undrilled sears that I can bend up or down with a torch to solve issues like this.  Same for bridles too. 
-Eric

[Jim Kibler]

Even the sear placement on the one Jerry shows is pretty bad.

[jerrywh]

 The photo I posted is of a Davis Twigg lock.  I don't understand the sear position but A trigger with a high bar would probably work OK. It doesn't look like other photos of the same lock for some reason.