On Sun, 18 Sep 2005 19:42:58 GMT, "david lang"
wrote:

Having problems with putting screws into the edge of 18mm MDF.

That's because you can't.

If you absolutely must, drill and glue hardwood plugs in there. Ideally
drill the plugs through the face perpendicular and screw across them,
like a wooden knock-down barrel nut.

Don't do anything to MDF that puts a tensile force across the
laminations. It might not delaminate today, but it will do.