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I purloined the following non-copyrighted information from the Kreg Tool Discussion Board. I edited the comments to match my HTML format. The following comments are a response to a remark made regarding clamping workpieces when screwing in pocket hole screws. The response was submitted by Jim Boelling (Kreg Tool Guy) on 11/1/2000.

A few weeks ago at a trade show, someone in the audience said that he had a Kreg Jig, loved it, and that he wouldn't part with it. But he was sometimes having trouble with the parts moving when he was trying to drive the pocket hole screws. And yes, he had secured the parts with a face clamp, but he didn't think that it was good enough (I assumed he meant clamping pressure) to do the job.

So... I thought it would be a good idea to talk about clamping parts, so here goes... First of all, people are not all alike, specifically in hand strength and dexterity. If manipulating any one of the face clamps (we have several sizes available) is a bit awkward, remember that you can always use another type of clamp to assist in assembling the parts in addition to using a face clamp. Of course, the physical size of the parts will sometimes dictate what you should do. The man I met, was joining a bottom rail out of maple that measured 3/4" x 3" x 60" long to a cabinet stile. Okay. Maple is a heavy hardwood weight wise, and when clamped to the smaller stile, also maple and much lighter in weight, that measured 3/4" x 2" x 36" long with one of our face clamps, he just couldn't keep the parts from shifting around.

The solution to his problem was a two-part answer:

• First, attach the face clamp to keep the two parts forming the joint flush.
• Second, add another clamp "in-line" with his long bottom rail to prevent the parts from shifting laterally. It's okay to double up with clamps in some instances, but we've found that in most general joining applications, a face clamp is enough to do the trick.

Let's assume that you are joining a rail to a stile for a cabinet face frame. In most cases a face clamp is enough to hold the parts until the screw is driven into the pocket hole. BUT, there are a few things you need to think about:

• Machining the Parts
  • The parts must be uniform in thickness. However, if they are slightly different, the difference can be offset onto the backside of the joint by placing the small pad of the face clamp on the thinner piece.
  • The edges must be accurately cut (i.e. edges at a 90-degree angle)
• Face Clamps (6", 9", 11", 18")...The Primary purpose of the face clamp is to hold the face surface of the two parts flush with each other in the same plane and to hold both parts with enough pressure to keep them from moving when driving the screw.
• Pocket Holes and Screws...The tip of the Kreg stepped-drill bit, drills a "guide" hole that is larger in diameter than the outside diameter of the threaded portion on any of our pocket hole screws, and is similar to drilling a "shank" hole drilled for standard wood screws. Shank holes DO NOT allow the screw threads to engage the walls of the shank hole. The self-tapping tip of our pocket hole screws, utilize the "guide" hole to contain the screw until the tip starts to drill it's own "pilot" hole out of the first workpiece (the piece with the pocket hole in it) and on into the second workpiece. Once the screw is fully seated at the bottom of the pocket hole, the threaded portion of the screw has driven itself via its' own "pilot" hole, into the second workpiece, which greatly reduces the potential for the screw to push the parts out of alignment with each other, something that a lot of people experience when using other types of screws in conjunction with pocket holes.

Remember that clamping two parts that form a joint, is a two-way dimensional relationship between the parts. If you experience the parts shifting when driving the screws especially after applying the glue to the mating surfaces, try this:

1. Apply the glue, then attach the face clamp to hold the "face surfaces" of the parts flush with each other in the same plane, then
2. Apply a long clamp (pipe, bar etc.) "in-line" with the joint being assembled.
3. Then drive the screws.

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