Question about Pocket Hole "Creep"

[Joe Vincent]

I understand one of the issues that some have had with using pocket hole screws, particularly for face frames where flush faces are needed, is misalignment due to what has been described as shifting or creeping.

Is this creeping something that gradually happens over time or is it just an issue of the screws pulling the faces out of alignment at the time they are inserted?

I'm just wondering if I should be concerned that joints that look fine now may "creep" out of alignment in the future?

[Joe Vee]

Joe,

I am by no means a pocket hole expert but have used my Kreg kit multiple time. I have found, if you have the 2 pieces of wood clamped and drill the pocket hole at the angle of the jig, then when the screw is inserted and tightened you don't get much creep. Also, if you are using hardwood, don't over tighten the screws. I have snapped a lot of screw heads off. Hope this helps

Joe

[Anthony Whitesell]

I have noticed if both pieces are not clamped when the screw is driven then the face opposite the screw may not be flush. The effect has been instant and I attribute it to the fact that screw is on an angle and being driven on an angle in a way that pushes the faces out of being flush.

[Jim Becker]

Effective clamping is absolutely essential to avoid this in my experience.

[Ray Schafer]

I have been considering using a couple of dowels in some cases to avoid the creep. I have also used hand-screw clamps to hold the joint in alignment -- this works well for face frames. When doing 90 degree joints, I just use a couple of bar clamps to hold the joint very tight.

[Chris Padilla]

http://www.sawmillcreek.org/showthread.php?t=8119

(Edit: sorry for the broken links but unfortunately Todd didn't load up pics to SMC)

[Josiah Bartlett]

Clamping the parts together and pre-drilling the holes helps even more. I wish Kreg would make a bit with the shoulder further up the shank (giving a longer tip) so you could clamp the mating parts together, drill the holes with the jig, and have pre-drilled starter holes in the mating side all in one swell foop. Maybe I'll customize on of the dull bits I have with a grinder and see if it works.

[Jim Becker]

Josiah, I suspect that it's intentional that the bit doesn't penetrate the second piece, because it would be larger in diameter than you want on that piece. Hence, the reason that the pocket screws are self-tapping. The tip of the step bit is a clearance hole that keeps the screw from binding on the host piece.

[Chris Padilla]

Josiah,

That could work but you need to be careful of the depth of the hole in the mating piece...don't wanna drill out all the wood such that the threads have nothing to bite on.

[Brian Dormer]

For pocket hole joinery (I'm speaking from experience with Kreg) to work - you MUST securely clamp the parts being joined. For most joints, this isn't a problem. For a few types of joints - you have to get creative in holding everything together while the screw goes in. Once the screw is in - the pieces shouldn't move relative to each other.

As for driving the screws - if you are snapping the heads off - you need to back off the torque on your drill/driver. The best solution is to use a driver with a slip clutch and set it so that the clutch slips at the point where the screw just bottoms out (start out a low torque and adjust up until you find the sweet spot). Overdriving the screw (especially in composite materials or softwoods) will strip out the hole and leave you with a loose joint.

[Larry James]

I agree with the comment about being securely clamped. That is a must, but not always easy.

I use a drill/driver just to drive the screw most of the way in and finish with a screwdriver, this is extra work but I have found it is worth it.

I use glue on most joints. I've been using the Kreg jig and clamps for several years and have never noticed "creep" after the joint is properly made.

Amazing how many pocket hole screws I use - Kreg must make their money from selling screws!

Larry

[Karl Brogger]

Glue is a must. I run 2 screws in anything over an 1 1/4". Over 4" I add a third screw.

Kreg has a really sharp angle but work well enough, especially if you can't justify spending $2500 for a Castle Machine.

[glenn bradley]

The following is, of course, JMHO: Guess I'll chime in. Unless I missed it, someone should mention the proper screws are critical. Clamping is important but you only need a snug grip if you are using appropriate screws. I fought creep and clamped tight enough to dent my material till I switched screws.

The threads should not cross the joint line where the two pieces meet. By this I mean the non-threaded shaft crosses the joint once the screw is tight. If they do, clamp the pee-wad out of it or it will want to creep (and probably will once you unclamp). I find it easier to just use the right screws.

This pretty well covers it: http://www.mcfeelys.com/tech/pocket-hole.htm

[Steve Mellott]

I clamp both pieces of wood to the surface of my workbench and then insert the self-tapping screws. I have never had a problem with "creep." I also glue all surfaces and have never had one fail.

Steve

[Joe Vincent]

Lot's of great tips. Thanks, everyone.