I’m building a workbench featured in FW’s Tools and Shops 2006. It’s made from birch plywood with a top of MDF. The plywood is cut down into 3-1/2″ lengths and then laminated to make legs, stretchers, aprons, etc. There is mortise and tenon joinery in the design. The one thing that’s confusing me right now is the pocket holes to be drilled into the aprons.
I made a pocket hole jig that’s set at 25˚ from FW, Oct.’91 No. 90.
Here’s the confusing part, the magazine article for the workbench says to drill the pocket holes on one side of the two outer apron pieces, before laminating the apron. Makes me think that the pocket hole is only going through the outer apron piece. Well, the plans for the workbench and the drawings in the magazine article show the pocket hole going through the outer apron piece and through the center apron slat. That would be well more than 25˚. It doesn’t specify anywhere what angle the pocket holes should be.
When drilling out the pocket hole, what sized bit should I use?
Here’s the link to the workbench article:
http://www.taunton.com/finewoodworking/ProjectsAndDesign/ProjectsAndDesignArticle.aspx?id=29507
Replies
I'm not sure what the actual angle is, but the commercial pocket-hole jigs are set such that the hole would be centered on 3/4" thick stock, I believe.
The commercial sets also use a stepped bit, so the screw threads catch only in the secondary piece, pulling the primary tight to it.
I tested the jig I made at 25˚ on a piece of scrap 3/4" and it came out centered. I guess the drawings are just confusing. I think the bit I need has to be big enough to pass the threads of the screws but not bigger than the head of the screw. BTW, are there specific screws used for pocket holes? I'm just using the deck screws suggested in the article.
I've never used pocket holes, but I believe the purpose-made screws have an enhanced shoulder and sockets for a square drive.
Pocket-hole screws come in various sizes, and are self-tapping. There's a choice of fine or coarse thread for hard or softwood. All have Robertson heads and a flat shoulder to stop the screw entering too far, unlike the deck screws. Some have an extra built-in washer for softer woods.
Jim
The 25 ° may be too wide , although centered the angle comes at a wide angle and will have the tendency to push the frame member down from the direction the screw is . When the screw is coming in from a steeper straighter angle it helps to pull instead of push . 12 ° may be closer .
the picture shows a face frame bit with fish tail insert and carbide spurs
dusty , a pocket screw user
I agree about the angle. Old Shopsmith manuals call for a 20 deg angle and Kreg jigs are 15 degrees.
This forum post is now archived. Commenting has been disabled