On 6/26/2014 10:57 AM, Grant Edwards wrote:
I'm about to make a sliding fence for my router table (something to
attach a box joint spacer fence to). The base is going to be a chunk
of malamine MDF with a Kreg miter bar screwed to the bottom. [HD had
a pallet of 3/4" thick 11" x 2' melamine MDF shelf boards on special
for a $3 each, so I picked up a few.] On top of that goes one of
these:

http://www.amazon.com/Craftsman-3152.../dp/B00F3BFZAQ

In addition to the aluminum miter rail (which runs along the front
side of the table), there will be a hardwood "outrigger" rail that
rides along the back edge of the router table top -- similar to the
design in Bill Hylton's Ultimate Guide to the Router Table. If you've
never seen one, it's much like a table saw cross-cut sled. The side
of the miter slot closest to the bit is going to be the reference
edge, so I'd sort of like to try making the outrigger sort of
spring-loaded, but I haven't quite figured out how I'm going to do
that yet.

Anyhow, I've never worked much with MDF and was wondering what tricks
there are for screwing stuff to MDF shelf boards.

For example, when screwing things to balsa, it's common practice to
put a drop of cyanoacrylate into the pilot hole so that it wicks into
and hardens the walls of the hole. You let the CA cure completely
before driving the screw -- so you're not gluing the screw in, you're
just using the CA to reinforce the walls of the pilot hole.

Any recommended tricks like that for MDF?


I've always found that Confirmat screws are, hands down, the best screws
for MDF or particle board. Unfortunetely, they don't come in very many
sizes and their shafts are quite thick so they might not work for attaching
standard hardware. Spax makes screws for MDF but I've never tried them;
their regular screws seem to do the job in other materials so their special
ones might be worth a try if you can obtain a few samples. If neither of
these work for you then some experimentation with regular screws and
various sizes of pilot holes might let you find a good compromise between
grip and distortion. Squirting some sort of thin non-water-based glue (to
avoid swelling of the fibers) into the pilot holes certainly shouldn't hurt
anything even if it doesn't actually help.