Kreg Pockethole Breakthrough

A reader’s question about pocketholes and melamine:

Dear Stu,
 
I have the Kreg master system and I am having trouble with joining 16mm melamine chipboard to get a strong and firm joint.
 
I am using the 5/8 setting on the jig as suggested for use with 16mm material as well as using  1” screws as also suggested, (course thread) as I am using chipboard.
 
I think my problem stems from the fact that I am trying to join two pieces of melamine together to make a small box.   It may also be that
I don’t as yet have a Kreg right angle clamp.  Could you please advise me as what I might be able to do to get a firm joint without the blowout
of the screws through the other side of the melamine.
 
I don’t have this problem with ordinary pine.  I have only just tried using melamine, I know it should work fine, I am just doing something wrong.

 

My response:

I have done quite a bit with pocket holes and melamine, and haven’t had a particular issue (after some fine-tuning).

Using coarse screws is correct for that sort of product, so no problem there.  It does compress more than timber, particularly when cutting into the ‘end-grain’, so some additional allowance has to be made for that (which is why your setup works for pine, and not melamine, or MDF for that matter).  I would tend to set the drill stop so it is drilling a little shallower than the suggested position.  You have plenty of capacity before the screw head ends up above the surface, and considering it is still punching through the other side, it has more than enough contact area with the material it is screwing into.  As a rough judge, you can work out how much length of screw is jutting out the other side, and decrease the stop position back that much, plus a bit more (you don’t want the melamine even bulging where the screw is)

This will give you a good purchase, allowing you to do up the screw tightly and avoid breakthrough.

The right angle clamp I do find very useful (the one where one end fits down into one of the pocketholes), but it isn’t going to help with this problem.  Fortunately, it is an easy fix 🙂

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