Parts aren't flush with pocket screws?

[Wade Lippman]

I am making a bed headboard with two rails and 14 slats between them. The rails and slats were exactly the same thickness. I held the slat to the rail with the Kreg clamp that is like a vise grip with two large flat plates. (https://assets.leevalley.com/Size4/1...clamp-f-50.jpg)
All the rails came out to be raised about 1/64"; presumably the screw going in forced it down a bit.

How can I prevent that in the future.

I wish I had waited to sand until after assembly, as I had to do it over again to get rid of the 1/64".

[Michael Burnside]

You are right to want to clamp when screwing the boards together. That said, it's hard to know for sure if the clamps you used were the right clamps for the pocket you were making without a picture of some sort. I have the clamps you linked but I rarely use them. For boxes, drawers, carcasses, etc., generally I just use my Besey F clamps as if I were gluing. One other important point when joining two flat sheets together or building a face frame, is that I usually try to clamp against a flat surface (i.e. my bench) and push down.

Sometimes it just happens though so don't beat yourself up too much.

[Kevin Jenness]

Clamp the parts endways as well as down flat to prevent them working out of plane. The problem is more acute with Kreg joints where the pilot hole does not go through, so the screw pushes a little slug of material ahead of itself as it enters the rail and tries to jack the pieces apart. Routed pockets with a through hole and lower angle are better in that respect but it still pays to clamp in both directions.

[Richard Coers]

I use a long 3/16" drill bit and drill a hole in the bottom of the pocket. If you Kreg bit isn't reaching all the way through the wood, then the screw tries to push wood between the two pieces. Trust me, it makes a huge difference! Also make sure the vise grip clamp is really tight. I have also used pipe camps to put more force on the joint before driving the screws. But the clearance hole for the screw makes the most difference.

[Rick Potter]

Kreg folks told me the bit does not go all the way through by design. Their explanation was that having the two pieces clamped together tightly avoids pushing the mating piece away.

I do mine on a melamine table with a simple L shape fence screwed to it to square up my project. Whenever possible, I push my face frame against the fence and then clamp, to avoid the work 'walking'. Works 'most' of the time.

I have acquired some of the clamping track Kreg sells and one of these days I will make a decent clamping table/track saw table.

[Richard Coers]

Kreg folks told me the bit does not go all the way through by design. Their explanation was that having the two pieces clamped together tightly avoids pushing the mating piece away.

I do mine on a melamine table with a simple L shape fence screwed to it to square up my project. Whenever possible, I push my face frame against the fence and then clamp, to avoid the work 'walking'. Works 'most' of the time.

I have acquired some of the clamping track Kreg sells and one of these days I will make a decent clamping table/track saw table.

That may be their recommendation, but I've drilled hundreds and hundreds in hardwood and drill out every single one after the first few did not result in what I wanted. I can vouch that the wood moves less. I'm not going to force anyone to ignore Kreg, just sharing what has worked for me for decades. I owned the first design in cast aluminum and they gave me a free update at a show about 25 years ago.

[Leo Graywacz]

If you drill the hole through it will move more. The secret I use for face frames which is one end grain part being attached to an edge grain part is this. Use glue. Put the parts together and use the Kreg clamp to make each part level. Make sure there is no space between the parts, even a small space will cause the part to shift. Screw the parts together and let the joint sit for 5 minutes or so for the glue to set. Then you can remove the clamp.

Ya, it's not instant but it keeps the parts level and it's much quicker than gluing up.

[Mike Mason]

Kreg folks told me the bit does not go all the way through by design. Their explanation was that having the two pieces clamped together tightly avoids pushing the mating piece away.

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The way that any woodscrew works best is to have a clearance hole in the first piece and a smaller diameter hole (or perhaps no hole with drywall screws in a softwood) that the threads bite into in the second piece. In this way, the screw acts like a clamp to tightly hold the pieces together. If the screw bites into the first piece, then unless the two parts are held perfectly tight against each other while being screwed together, any small gap will remain after screwing, no matter how tightly you screw them together. This is the same way that machine screws work, you never find two metal pieces that are bolted together and have threads cut into both pieces.

The reason that the two pieces shift vertically in the Kreg jig is that you are screwing them together at an angle, in which case the clamping force of the screw has a vertical component. Unless you very tightly hold the two pieces down flat to counteract this vertical force component, there will be some shifting. I've not used my Kreg jig all that much, but when I have, I haven't experienced the shifting. I use the same sort of vise grip clamps with large round pads, but I clamp across the joint very tightly and use wooden blocks to prevent me from marring the workpieces.

[Rick Potter]

I suspect that using glue a bit too heavily will actually keep you from getting the clamp tight enough. A thick glue layer may be keeping the two pieces of wood too far apart when you clamp. A lot of squeeze out would be an indication of that. My preferred method is to butter only the end grain and wait a couple minutes to allow the glue to sink in a bit, then clamp it and screw it down. YMMV

I also made my first kitchen with the original aluminum jig, and the small vise grip clamp they sold at the time. That was in the late '70s/early '80s. My daughters family lives there now, and the kitchen has had zero joints loosen in the 40 years since.

I have my fathers original aluminum one also, which is a bit different than the one I bought back then. Pretty neat.

[Leo Graywacz]

Yes to what you said about the glue putting a space in between but I think it's more of a lubricant that helps the wood shift. I've noticed without using glue there is usually less shifting because of the roughness of the two pcs cause resistance and when you add a glue layer it can be considered a lubricant because it allows the pcs to float on each other even though the "float" is only a few thousandths of an inch.

[Bernie Kopfer]

I had the same problem the OP described years ago and since then have put a small amount of glue in the joint. That has eliminated the movement for me.

[Rick Potter]

Years ago, when Craig (Kreg) Summerfeld was selling the Kreg jig at shows, he would mention how important it was to set the stop collar slightly above the jig, which means it doesn't go through. The screws are self tapping and work much better than drywall screws. He also mentioned glue is unnecessary, but if you use it don't overdo. He was a cabinet maker and built a lot of kitchens.

Drilling deeper into the wood in order to have the through hole has two problems. The deeper pocket leaves less meat on the piece for the head to tighten to, making it weaker. Deeper pocket also changes the point at which the screw enters the companion piece, the deeper you drill, the lower the screws enter the other piece, which may cause it to split. The split is also for two reasons, the uncentered, lower entry point plus the fact the screw now goes in deeper.

Years ago I made up a bunch of trial joints on oak, so I could understand this. I varied the depth of the holes, and found that there isn't much room for change before bad things happen.

The Kreg jig is part of a system, and the instructions should be followed for best results. The type screws are super important, and drywall screws are a no-no. The angle on the head is a wedge that will weaken the small seating area the drill makes.

I had a Castle machine for a while and it was really nice, but for DIY guys like me the Kreg system has worked fine, and is affordable. And it fits in a drawer.

[Michael Burnside]

Yes to what you said about the glue putting a space in between but I think it's more of a lubricant that helps the wood shift. I've noticed without using glue there is usually less shifting because of the roughness of the two pcs cause resistance and when you add a glue layer it can be considered a lubricant because it allows the pcs to float on each other even though the "float" is only a few thousandths of an inch.

I had the same problem the OP described years ago and since then have put a small amount of glue in the joint. That has eliminated the movement for me.

Odd, you're both suggesting the same thing has different outcomes. Hmmmm. I generally glue my joints but I'm with Leo on this one, but still suggest that good clamping is the way to go. Having said that, I haven't really had much of a problem the last couple of years since switching from Kreg to Castle 110, which is a much better system for pocket hole joinery IMHO.

[Leo Graywacz]

I did actually say both things about the glue. Don't use a lot or it's like lubrication and can cause slippage. But when you do use glue you can't release the clamp until the glue sets, which is usually about 5 minutes fort TBII which I use. If you put glue on the joint, clamp tight and drive the screw(s) and release the clamp right away the joint will slip on the glue and misalign. If you don't use glue then you can release the clamp right away. I use glue because no glue in the joint will show up in the clear coat.

[Richard Coers]

To summarize, every methods each person uses works for them except for poor Wade. LOL Craig Summerfeld used to stress that everyone use a corded drill because of the higher rpm to eject chips too. I think that went out the window since corded drills are few and far between now.