On Wed, 5 Jul 2017 10:25:23 -0700 (PDT), trader_4
wrote:

I don't even see the need for a jig. He can just clamp the two pieces
back together, drill holes in from the top, put it together with glue
or construction adhesive and dowels. But it also looked to me like
the roller part on top had wide brackets and his idea of drilling holes,
using glue, adhesive, to help anchor the screws plus putting in under
the metal brackets, would bond it too, without attaching the original
piece that he cut off.

Maybe, but he didn't say how much he cut off. As I think he only
really has one shot at making the repair, and knowing how difficult it
can be to accurately freehand drill, multiple, relatively deep holes,
I would urge him to use a self-centering doweling jig, like this one
from HF. $15 is a relatively small investment to insure he doesn't
create another CF and run the drill through the outer surface of the
masonite.

https://www.harborfreight.com/self-c...jig-41345.html

As it is, I think he only has a 50/50 chance of effecting a functional
repair with expending excessive time and resources. And, let's face
it, the door sounds like a piece of crap anyway.