On Wednesday, July 5, 2017 at 8:57:48 AM UTC-4, wrote:
On Wed, 5 Jul 2017 03:49:16 -0700 (PDT), DerbyDad03
wrote:

On Tuesday, July 4, 2017 at 7:34:19 PM UTC-4, wrote:
On Tue, 04 Jul 2017 22:44:07 GMT, Dave
m wrote:

I bought a sliding barn door that was the right width but a bit too tall. The
bottom has a groove for a guide, so in order to shorten the door, I cut a
couple inches off the top.
The trouble is, I cut off the hardwood at the top of the door that the roller
assembly screws into and now all that's left is the particle board interior.
The particle board isn't strong enough to hold the weight of the door on the
rollers. So... I need to figure out how to attach the rollers to the top off
the door, with only particle board to screw into. (In retrospect, I clearly
should have cut extra height off the bottom - too late now.) I'm wondering if
I drill holes, fill them with epoxy, and then set the screws in place if that
will be strong enough. Thoughts?

Here is the door for reference:
http://www.homedepot.com/p/Masonite-...7590/206193108

Saw a slot in the top of the door 3/4" wide and as deep as your blade
will go. Glue a piece of hardwood in there, screw into that.
Perfect would be a dado blade in a table saw but you could do it with
a circular caw and the fence. Set it to cut the outsides of the 3/4"
slot first then eat out the middle. Start smaller than 3/4 and sneak
up on it. Clamp 3-4" of material to the side of the door, even with
the top to get a stable base to work from. Laid flat and clamped on a
table or the bench, hang the fence from the top surface with your
clamped "base" on the bottom using the wide side of the saw plate
against it.
Just be sure everything is stable before you start the saw.

A router would probably be the better choice for cutting the dado.

You just have trouble getting it very deep.
If the surface of the door is not important, you could use one of
those cylinder shaped nuts. That is what the furniture guys use in
that sawdust material.

How deep do you think it needs to be? He mentioned that he cut off "a couple
of inches" but he didn't say that all 2€œ were hardwood or how long the screws were.

Even if he needed the full "couple of inches" you can get straight bits with 2" cut lengths.

e.g. https://www.amazon.com/Freud-12-142-.../dp/B0000225VZ

Multiple shallow passes could easily get him the full 2". A simple jig with a straight edge
clamped to the door and he's good to go.

Of course, he could also use the tool shown at 3:00 of this video. ;-)

https://www.youtube.com/watch?v=DiPyLtDpHto