Lock size?

[Cherrybow]

I have read through a lot of building threads and several times it is said to pick the right size lock for your barrel. My question is: What determines the “size”? The length of the plate or the depth at the bolster? Could someone explain this for me.

 

[Flintandsteel]

The height of your lock plate compared to the width of the barrel at the lock.
There is a lot of leeway there. It’s hard to get the right shape on the lock area if your lock is way too tall, or way too short.
There are more things to consider, but that’s the main thing.
Hers

 

[Flintandsteel]

This is an A wt barrel, using a M&G classic. Between large and small Siler, with wider bolster to maintain wrist dimensions.

 

[Cherrybow]

Thank you!

 

[EC121]

Another consideration is if the lock is too small, the plate bolster too shallow, or the barrel too big, the mainspring can hit the barrel. You have to get pretty far off the norm, but it has happened.