How do you prevent pieces moving when using pocket holes?

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Forum topic by InstantSiv posted 03-20-2014 10:25 PM 6072 views 0 times favorited 16 replies Add to Favorites Watch
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262 posts in 1529 days

03-20-2014 10:25 PM

Topic tags/keywords: pocket hole kreg clamp jig screw flush

Hi, I cannot figure why I am still getting movement when clamping pieces and using pocket holes(see pic for orientation of pieces, sorry for quality… drawn on tablet). I need the two pieces to be perfectly flush with one another because I am flush trimming and using those as the bearing surface. Kreg makes a specific clamp for that orientation but the reviews say that it’s prone to breaking. I made a quick clamping jig(pictured) to clamp the pieces but the pieces move and are not flush.

What are your thoughts?

16 replies so far

View levan's profile


472 posts in 2913 days

#1 posted 03-20-2014 10:35 PM

lOOKS LIKE THAT SHOULD WORK. Must be slipping on part b. Maybe you could put a clamp from the end of part B to the corner jig, If you have a deep ingagement clamp long enough. You might also try putting stick on sand paper on you corner jig to help with slipping.

-- "If you think you can do a thing or think you can't do a thing, you're right". Henry Ford

View a1Jim's profile


117032 posts in 3511 days

#2 posted 03-20-2014 10:47 PM

Maybe I’m saying the same thing as Lynn
clamp part “B”to the bench then put a board as a stop on the end your going to screw together also on part “B”
put a clamp on the stop block and the other end of part “B”. The stop block will prevent Part”A” from slipping outward.

-- wood crafting & classes

View Nicky's profile


695 posts in 4026 days

#3 posted 03-20-2014 11:00 PM

I just did a fair amount of experimenting with pocket holes. If you screw down to tight, the joint will be uneven. Also after drilling the pocket holes, try a pilot hole with the pieces clamped (1/8” worked for me)

I’ve gotten close but not perfect.

-- Nicky

View Loren's profile


10101 posts in 3582 days

#4 posted 03-20-2014 11:16 PM

Glue them first.

View MT_Stringer's profile


3160 posts in 3165 days

#5 posted 03-20-2014 11:23 PM

Clamp the heck out of them. You are about four clamps too short. :-)
I clamp the workpieces to the table.

-- Handcrafted by Mike Henderson - Channelview, Texas

View Redoak49's profile


3133 posts in 1922 days

#6 posted 03-20-2014 11:30 PM

I do not have that kind of problem but you need to clamp things tightly and not let them move. The idea for sandpaper glued into the jig is a good one.

View Whiskers's profile


389 posts in 1961 days

#7 posted 03-21-2014 01:49 AM

One thing that helps with pocket holes to prevent movement is don’t run them all the way down tight at first. Get screws in both holes most of the way than finish them off. You might also want to add a sliver of 1×2 along the inside edge on top of part B and up against A so that A is engulfed on both sides.

View pintodeluxe's profile


5595 posts in 2747 days

#8 posted 03-21-2014 01:53 AM

Use the kreg brand clamp, and set it fairly tight. It works much better than a standard F style clamp. Also, you can pre-drill the pocket scew with a pilot bit, but it is usually not required.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View MT_Stringer's profile


3160 posts in 3165 days

#9 posted 03-21-2014 02:03 AM

@OP – I was looking at your drawing again. If it was me, I would rotate your workpieces 90 deg to the left. That way, the piece with the pocket holes is on the table.

Use whatever means you can cobble up to capture the vertical piece so it can’t move backwards , left or right.
Clamp the piece with the pockets to the table and run the screws in. I have done this before. It should pull up tight.

Good luck.

Note: It is not beyond me to drill holes in the table, or make up temporary clamping jigs so I can secure the workpieces. I do whatever it takes. Sometimes those videos you may see on UTube, aren’t as simple as it seams.

Good luck.

-- Handcrafted by Mike Henderson - Channelview, Texas

View cabmaker's profile


1706 posts in 2743 days

#10 posted 03-21-2014 02:13 AM

I used to do it with a ritter table and pneumatic plungers. Check em out!

View Craftsman on the lake's profile

Craftsman on the lake

2776 posts in 3371 days

#11 posted 03-21-2014 02:28 AM

Clamping it correctly should work but I often assemble things with a pin nailer. The nails are about the size of a thin sewing needle with no head. You can’t see the place it was nailed unless you get really close and really hunt for it. And they hold amazingly well. Glue / pin nail / then screw.

-- The smell of wood, coffee in the cup, the wife let's me do my thing, the lake is peaceful.

View InstantSiv's profile


262 posts in 1529 days

#12 posted 03-21-2014 12:54 PM

Thank you everyone for the responses.

I kinda dismissed part b moving because I didn’t see any movement while screwing. I’ll have to rethink that and secure part b. I’m going to try the sand paper first and if that doesn’t work then try to clamp part b to prevent movement.

I’ve also heard of sprinkling sand, rubbing sand paper together, over the glue to prevent two pieces from shifting around while gluing. Anyone heard of this? I think it was to prevent minor shift while clamping so I don’t know how well it would work with pocket joints.

Thanks again. I’ll report back with my findings.

View InstantSiv's profile


262 posts in 1529 days

#13 posted 03-21-2014 04:58 PM

Okay just got done experimenting a little.

Sand paper on the jig still caused movement. I was a bit disappointed this didn’t work because it was a super simple and elegant way to solve the issue. I then tried what MTStringer suggested(putting part A flat on the table) and the experimental jig I threw together worked!

Part C & D was just scrap wood I clamped together(not shown in pic). C/D was clamped to the table top with a single clamp. Part B is pushed into part C/D by Part A. Part A is clamped to the table. Part B was simply held down by my free hand because I don’t have clamps longer than the piece. Perfectly flush tight joint.

I’m still going to have to design a better jig than this but I think it’s a working concept. Thank you MTStringer for the suggestion and others who have chimed in. This has been racking my brain for a while now.

View a1Jim's profile


117032 posts in 3511 days

#14 posted 03-21-2014 05:01 PM

After all is said and done I agree with Loren just glue it first ,let dry then ad pocket screws.

-- wood crafting & classes

View bowedcurly's profile


519 posts in 1663 days

#15 posted 03-21-2014 05:14 PM

use a mig welder, just kiddin, pilot holes work well, and bigger clamps

-- Staining killed the wood<<<<<>>>>>Dyeing gave it life

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