Robert Allison writes:
blueman wrote:
I need to mortise out a door to accept a Baldwin mortise lock.
I know that the tolerances are really tight (with errors being pretty
disasterous) and that locksmiths typically use a router with a fancy
mortising jig.
However, I have not been able to find the jig in the local tool
rental
shops, so I was wondering whether there are any reliable alternative
approaches or sources for a good jig?
Thanks

What is really tight is the mortise for the plate that the plunger
passes thru (the one that you see when you have installed the mortise
lock). For the interior, it is not that critical. You can do it with
a drill and a good chisel.

First lay out the two areas to be mortised. There will be one for the
plate and one for the lock (a rectangle within a rectangle). Select
the proper size drill bit and drill a series of holes within the
layout marks for the lock. Use the chisel to clean out the rest.
Then, use the chisel to mortise for the plate.

You should drill the handle holes after doing this, and from both
sides, rather than straight through the whole door.

My concern is that I need to keep the drilling & chiselling "plumb" or
otherwise I will "poke" through the door. My understanding is that
there is not much wood left standing between the mortise hole and the
door faces.

I guess I could always just be careful, but this is not a mistake you
want to make (and maybe I should just dig into my pockets and get a
locksmith to come out to my house...)