Pocket Holes and MDF

[Gene E Miller]

Greetings & Salutations,

I am about to embark on a project that will entail making a case
out of MDF. I am also going to try to use my new Kreg Pocket Hole Jig to attach the panels of the case.

My question is has anyone done this or have any knowledge of this method being used on MDF for case work before?

It seems that I have seen it somewhere but am not sure and before I start to make sawdust I would like some outside opinions as to whether this would be a good method of attaching the case sides as well as a few fixed shelves.

Any comments will be welcome as usual.

Thanks,
Gene

[Jamie Buxton]

The screw heads tend to pull right through the end of the MDF board the hole is in.

[glenn bradley]

I would pass on the PH if you really want to use MDF. Rabbets, dados and / or Confirmat screws are better. If you really want to use PH then use plywood. JMHO.

[Paul Demetropoulos]

What Glenn said, dado, rabbett and confirmat screws.

If you don't use the special bit for confirmat screws, you need to drill a clearance hole in the top mdf board. Otherwise the back of that board will
"flower out" and boards won't come together.

[Gene E Miller]

Greetings & Salutations,

Thanks guys for the quick answers. I kind of figured that PH use might not be acceptable in MDF. I was just trying to figure out a way to use the new jig when it gets here and that is the only project I have in the shop at this time.

I do have 12 feet of base and upper kitchen cabinets to build for the LOML very soon. I expect I will get to work that new jig really well on that one.

I will resort back to dado's and other methods for the current project.

Thanks again,
Gene

[Peter Quinn]

My results with PH screws and MDF have been poor at best. Screws pull out, they pull through, the receiving end splits, its a mess. I prefer biscuits for but joints in MDF if necessary, or dados and screws with glue.

[Mike Gager]

weird, i had no problems with mdf and pocket screws

use the right screws and it should be fine

[Dave Lehnert]

I just did a small project with pocket screws and MDF and so far so good but will need a little more time to see if it holds up. I was a shop jig.

[Sue Wise]

I have not had much luck with Pocket holes/screws and MDF.

[Mike Gager]

im curious what you guys were building when you had bad luck?

did you use glue with the pocket screws?

[Cliff Rohrabacher]

MDF is only tough on the outer skin. The innards are pretty poorly compacted. Pocket screws will likely fail in that application.

[Greg Hines, MD]

I have heard of problems with screws pulling out of both MDF and particle board, and have heard of people inserting dowels or Dominos into the area that they were going to be putting screws, for that very reason.

Doc

[Bob Sanders]

I've used pocket holes with MDF a ton, with virtually no problems. Obviously it could depend on the specific application you're talking about... but in my experience, its a seamless operation. Very strong results.

[Gene E Miller]

Greetings & Salutations,

Thanks again for all of the responses.

The application I was thinking of using PH and MDF in was a fairly large
case. Approximately 48"H x 60W x 24"D.

In a piece that large I am pretty skeptical as to how well the PH screws will hold.

I would be using glue as well as the PH screws and may give it a shot for one side and see if I like the results before assembly of the entire case.

I still haven't decided for sure yet. I will post again if I do go that route but for this project I may just use dado's and confirmant screws.

Thanks again.

Gene

[Chris Padilla]

MDF quality varies all over the place. Some stuff is quite soft in the middle and other stuff is pretty stiff throughout.

Generally, regular old wood screws just don't do well in MDF due to its density. Pilot holes are almost always needed to clear out material. MDF also doesn't support itself well at all as it'll sag under its own weight.