Kreg help needed

[Jeff Cord]

I just got a pocket-hole jig and am having problems getting the joints aligned.
I drill the holes and, using their clamp, get both pieces perfectly aligned (the face surfaces are perfectly smooth) and clamped to my table.
Then, when I drive the screws one of the pieces (the piece not drilled) is no longer aligned (smooth) with the other piece (the piece I did drill) and there is a small lip.
Is there a trick I'm missing to keep this from happening?
I realize that a bit of sanding will remove the lip but I cannot believe that everyone is having this problem.
Jeff

[Frank Pellow]

Jeff, I assume that you are talking about an edge to edge joint. I have had the same problem that you mention when using just the Kreg clamp. The only way that I found to avoid having this happen was to clamp both pieces to a flat surface using other clamps before driving in the screw.

I certainly would be interested in hearing any other way to eliminate the problem.

[Mark Rios]

On the face frames that I just did I had a good learning curve. I found that if I clamped thr face and the back of the pieces they moved less. In other words, I didn't clamp the pieces to anything just together with the large flange of the clamp on the face; small flange on the back, just out of the way of the screw holes. Sometimes I would have to adjust the clamp so that the large flange was more on one side of the joint or the other, thus putting more force on one side of the joint or the other. About half way through, I found that if I also used one of my K-body clamps to pull the pieces together that I had ALOT less movement.

[Mike Goetzke]

I even went as far as applying self-stick sandpaper to the OEM clamps. I recently installed a Kreg table clamp into my workbench ( http://www.kregtool.com/products/pht/product.php?PRODUCT_ID=37 ). This clamp applies way more force than the std. one. I also find this clamp handy to hold down boards when I cut biscuit slots too.

Mike

[Jeff Farris]

Tighten up your clamp a little, and as someone else said, just clamp the joint together, not to a table. Put the large clamp pad on the face side of the joint and the small one by the screw holes. When you run the screws in, set your clutch pretty high, so that it applies considerable torque to the joint. It should pull together almost perfectly flush.

[Rick Christopherson]

The best way to correct this problem is to understand why it is happening.

When the screw tip leaves the first piece, but before it pilots into the second piece, it pushes the two workpieces apart. This is because the screw threads have some grip on the first piece, and continue to advance before they engage the second piece. This slight gap, coupled with the angle of the screw, causes the tip of the screw to enter the second piece slightly lower than it would if they were tight. When you draw the two piece together, it pulls the second piece upward so the screw holes align.

First off, ignore what the instruction manual tells you about setting the drill bit depth. You want the drill bit depth to be close enough to penetrating the endgrain that it actually blisters it slightly (breaks the fibers). Ideally, the drill bit would completely penetrate the end of the wood, but this would give you a weaker shoulder.

Then, use your fingernail or chisel to clear the blistered fibers from the end grain to allow the two pieces to fit together without a gap.

Regardless what else you do, stop the pieces from separating as the screw penetrates the second piece, and your alignment problem will dissapear. For critical joints, you might consider clamping the two pieces lengthwise to keep them from spreading.

[Ed Labadie]

Rick is correct.
I set the Kreg drill up per the instructions & then go back with a small drill & drill the hole all the way thru. Then clean up with a hand sanding block. I think any lost strength by doing this is made up for with the glue. I still clamp the joint while assembling.

Ed

[Mark Pruitt]

Going on what Rick said, I would think that another factor that complicates the issue is the forward-force with which the screw is driven into the boards. And I would think that the solution is in the mantra, "Let the tool do the work"; i.e. let the mere force of the spinning screw "pull" the screw into position. I need to experiment more with this but theoretically it seems that doing this would alleviate the problem.

[Bob Rufener]

I have had the same problem with mine. I usually glue the face frames as well as screwing them together with pocket holes. I have found that if I glue the joint and clamp it, let the glue set up and then screw it, I get better joints. It takes a bit longer to do because of the waiting time for the glue to set up but the results are good.

[frank shic]

jeff, you might want to try the larger FAC clamp that kreg makes and formerly included in their kit. i had the same problem as you did until i bought one of them. make sure that the clamp is set TIGHT. using this method saves on the extra steps that others have recommended: lengthwise clamping and drilling the mating piece.

[Lee Schierer]

As the others have stated, the joint is not being held tight while the screws are inserted. Proper hole depth helps so that the screw exists the first piece on the center line. You must also hold the second piece tightly against the first otherwise a mis alignment will occur. More clamping pressure should be all that is needed. Also make sure you are using Kreg Screws for the proper type of wood. The make hard wood and soft wood threaded screws.

Some other brands of screws don't self drill as well and will produce more problems with joint alignment.

[Russ Filtz]

The trick is to use a piece of simple notebook paper folded in half. Slip the folded paper behind ONLY the screw head piece and clamp into the jig. After you drill the holes, the extra gap will allow the screws to pull tight and into proper alignment. Without the extra gap, the screws pull the piece past flush and now you have the problem you're describing.

Depending on how bad your alignment is off, you may need more/less folds.

[Jim Becker]

The only thing I can add to this conversation is to check the clamp before you screw each joint...the Kreg clamp can tend to "loosen up" quite sporadically and that will also help cause the issue you are facing.

[Joe Chritz]

For those who recommend not clamping to a table.

Are you using the kreg clamp of something else?

I have been assembling the last few face frames by clamping the joint to the table using a K-body clamp. Sometimes one on each piece but mostly just over the joint. I have been getting almost totally flush joints so far.

I crank the pressure on though so maybe that helps.

Joe

[Mark Rios]

For those who recommend not clamping to a table.

Are you using the kreg clamp of something else?

I have been assembling the last few face frames by clamping the joint to the table using a K-body clamp. Sometimes one on each piece but mostly just over the joint. I have been getting almost totally flush joints so far.

I crank the pressure on though so maybe that helps.

Joe

I use the clamp that comes with the kit; The clamp with two swivel pads with one pad being a little smaller than the other. Then I clamp the two pieces of faceframe together lengthwise as I mentioned above. I don't really crank it down but it is tight. Again, I started doing this about halfway through my job and it really helped with the line up issue.

[Steve Clardy]

Look in here at my post. Simple fix.

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

[John Stevens]

As you can see from the solutions, with the Kreg pocket hole jig, you can either have speed or accuracy, but not both. Best of luck to you with whichever one you choose.

[Michael Adelong]

I was considering trying the pocket screw route until I read this thread.

Seems to me that the plate jointer and biscuits are less troublesome. Am I missing something here? I thought that pocket screws were supposed to be both faster and easier to align?

Thanks,
Michael

[Joe Unni]

Jeff,

Here is what has worked for me.

1. Make sure your lumber is planed the same thickness. I know this sounds dopey, but before I got a planer the 3/4" S4S lumber that I bought was not always exactly 3/4". This helps a ton.

2. Secure a piece of flat 3/4" cabinet ply to your bench big enough to support the majority of the pieces you will be joining. Let the ply overhang your bench by about 2"-3".

3. Clamp the joint to the ply using the clamp that came with the jig with the large pad on the screw side. This way the ply acts like an extension of the clamp (i.e. a huge flat face). Make the the clamp quite tight and check it often as I agree with Jim that it does loosen easily.

Since I've started do this my joints require little or no sanding. Depending whether you glue the joint or not, you may have to deal with a little glue squeeze out.

Overall with this method I've been able to achieve both speed and accuracy. Pocket holes are a really great addition to your woodworking arsenal. Like ANY tool you have to learn IT.

Good luck,
-joe

[frank shic]

michael, the pocket screws are much faster than the biscuit jointer when you take into account the clamping time for the glue. alignment with the biscuits is easier but you end up needing to make alignment marks across the mating pieces or build a jig to slot the ends not to mention that you'll need to change out the blade (and you can only do this with either the pc557 or the lamello).

everything has trade-offs, but for me the pocket screws are still the fastest. i just built a set of kitchen cabinets and i hate to think how much extra time i would have spent biscuit jointing the face frame pieces especially on the extra wide cabinets with all the intermediate stiles and rail!

[David Eisenhauer]

I agree with the last post. If it is advisable to: clamp lengthwise, add paper shims, drill a blister and shave the debris off, drill through from the other side, use different clamps, clamp either to or never to the bench, glue first-let dry-then install Kege screws, then it seems that biscuits would be better served. I have heard of way too many people that have progressed from biscuits to the Kreg system for the system to not work, so something is not right somewhere. Back in the 80's, I thought biscuits were such an improvement over a worn out doweling machine, that I figured I had solved a big PIA operation in my shop when I went to biscuits. A few years ago, I tried the Kreg system out when it was just the single metal jig that was moved around to wherever you needed it. I couldn't convince myself that it was faster than the setup that had evolved in my shop over many years with the biscuit method and various shop jigs out of scrap that became part of the setup. Probably not a fair comparison, but I kept on using biscuits. Lately, with so many advocating the Kreg, I've been thinking of getting the latest "Super Duper" Kreg system and giving it another try, but I wonder if it will be worth it?

[Phil Maddox]

Try to make sure you have the smaller clamp pad centered on the joint in such a way that if there is a difference in the thickness of the two pieces that it will pivot and hold both. You may need to increase the pressure a bit.


Good luck

[Howard Rosenberg]

But there is one thing to add here.

I've been using pocket screws to make a pair of patio benches and table out of (YIKES!) ipe.

If the wood you're using is a hard hardwood, you may need to pre-drill the piece you're joining to. You've got to do this at a matching angle.

It's not hard, you just need two drills - otherwise you'll drive yourself crazy with scwitching bits and drills throughout the job.

After you drill the pocket hole, take your second drill and poke out the last pieces of wood.
Clamp both pieces into their final position.
Use the second drill to approximate the angle of entry into the piece to be joined.
Separate the clamps.
Drill further at the same angle into the second piece.

They should mate ok.

It works on ipe, which seems to be as hard as concrete....

HTH
Howard

[Joe Chritz]

FWIW....

The problems with pockets screws are not nearly so troublesome as it would appear from reading the posts. The ability to go from driving the screws to setting the frame aside and do another is the biggest advantage, for me at least.

When I did my kitchen I did not have a pocket hole system and used a PC557 biscuit jointer. It does well but there is still alignment problems occasionally and as mentioned all parts have to be marked and clamped.

They are usefull for lots of other things and a manual jig is cheap enough to have around and try.

Joe

[glenn bradley]

Also check into the type of screw. I have much better results with the design that has threads only on the last 20% or so of the screw body. This prevents the threads from engaging both pieces of wood. The "second" piece is drawn to the first.

[Dale Thompson]

The best way to correct this problem is to understand why it is happening.

When the screw tip leaves the first piece, but before it pilots into the second piece, it pushes the two workpieces apart. This is because the screw threads have some grip on the first piece, and continue to advance before they engage the second piece. This slight gap, coupled with the angle of the screw, causes the tip of the screw to enter the second piece slightly lower than it would if they were tight. When you draw the two piece together, it pulls the second piece upward so the screw holes align.

First off, ignore what the instruction manual tells you about setting the drill bit depth. You want the drill bit depth to be close enough to penetrating the endgrain that it actually blisters it slightly (breaks the fibers). Ideally, the drill bit would completely penetrate the end of the wood, but this would give you a weaker shoulder.

Then, use your fingernail or chisel to clear the blistered fibers from the end grain to allow the two pieces to fit together without a gap.

Regardless what else you do, stop the pieces from separating as the screw penetrates the second piece, and your alignment problem will dissapear. For critical joints, you might consider clamping the two pieces lengthwise to keep them from spreading.

Rick,
AMEN!! :) Any "bite" on the first piece will offset the joint with the second piece. There are two ways to get around this. Either set the drill to penetrate the piece a little deeper than the template on the jig or redrill the small end to make SURE that you have a "pilot" hole for the screw. ;) :)

Dale T.