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Wood movement, glue-ups, and pocket screws

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Forum topic by Pthomas180 posted 04-28-2018 01:59 PM 1547 views 0 times favorited 7 replies Add to Favorites Watch
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Pthomas180

10 posts in 514 days


04-28-2018 01:59 PM

Topic tags/keywords: wood movement table glue up joinery tips woodworking pocket screws

I have a quick question. I am aware of the issues that accompany table top glue ups and wood movement. I don’t own a domino or biscuit joiner. So I am wondering if I can use (sparingly) some pocket screws to assist with alignment during glue up of a panel for a table top. I wouldn’t use this method to attach the top to the table base. And I wouldn’t really depend on the pocket screws for structural integrity. Just some screws on the bottom of the table top (out of sight) purely for alignment during glue up.

Any thoughts, concerns, or suggestions would be very helpful. I suppose I could use dowels, but seems like pocket screws with a simple Kreg jig would be much faster.


7 replies so far

View TimInIndiana's profile

TimInIndiana

145 posts in 559 days


#1 posted 04-28-2018 02:21 PM

I’m no expert for sure – but why not just use cauls to keep everything aligned?

Fine Woodworking has a nice article that demonstrates how to use them.

View Dustin's profile

Dustin

689 posts in 1159 days


#2 posted 04-28-2018 02:22 PM

I think if alignment is your goal, the pocket screws will be less effective and more of a pain to use then simple clamping cauls. If you google this, you’ll get plenty of recommendations to help with your glue up.

Also, make sure you’re using the right clamps. It’s not that f-style clamps can’t work for this application, but it’s certainly easier using parallel or pipe clamps, or some of those aluminum channel panel clamps HF sells.

-- "Ladies, if your husband says he'll get to it, he'll get to it. No need to remind him about it every 6 months."

View Rich's profile

Rich

4555 posts in 1008 days


#3 posted 04-28-2018 04:02 PM

Part of the difficulty of using pocket screws is keeping the boards aligned since the screws go in at an angle, so as Dustin said, it’ll make the glue up harder.

I third the clamp and caul suggestion.

-- Knowledge is not skill. Knowledge plus ten thousand times is skill. -- Shinichi Suzuki

View WyattCo's profile

WyattCo

93 posts in 523 days


#4 posted 04-28-2018 04:07 PM

As the others noted, the pocket screws will work against you. They will cause a glue up to “barrel”.

View Loren's profile

Loren

10477 posts in 4067 days


#5 posted 04-28-2018 04:15 PM

There’s some debate about the “salt trick”,
which is where you put salt in pva glue to
prevent slippage as the clamps are tightened.

Some say it works and others say it makes a
weak joint. I was going to try it myself but
haven’t yet because of the debate.

One thing I have done that works well is to
put in little wire nails and clip off the heads.
Then as you tighten the clamps the nails
keep the parts in alignment.

View Woodknack's profile

Woodknack

12842 posts in 2799 days


#6 posted 04-28-2018 05:09 PM

I use c-clamps on the ends and a dead blow to correct any center misalignment, always worked for me but cauls are probably the best solution.

-- Rick M, http://thewoodknack.blogspot.com/

View Rich's profile

Rich

4555 posts in 1008 days


#7 posted 04-28-2018 06:22 PM

Down around 12 to maybe 18 inches clamps on the ends of the joints are fine if your boards are flat. If the joints are longer, or if you’re alternating the wood to eliminate a slight bow, cauls are really needed.

I made a caul template out of 1/4” MDF and gave it approximately a 1/16” rise per 12” run on the edge. I then used it with a flush trim bit to make a couple dozen cauls of three different lengths and added red vinyl stucco tape to the curved face so they don’t get stuck in the glue.

They work great with F clamps on the ends of them. Perfect glue ups.

-- Knowledge is not skill. Knowledge plus ten thousand times is skill. -- Shinichi Suzuki

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