# Pocket hole screws



## Barry747 (Jun 16, 2011)

I am going to build a replacement top for a coffee table. The first picture shows the existing top which is 39” X 39”. It is a veneer on plywood. The edges are supported by a frame of some kind of composite. I will be replacing it with a walnut and maple top similar to the second picture, which I found on the internet.

The inside part of the table will be constructed by edge gluing 6 boards 5 ½” X 33”. I have never glued up a panel this large although I do have enough clamps to handle it. Hard to believe I actually have enough clamps for a project. That’s one in a row for me. Anyway, in the past I’ve used cauls to keep the boards flat while the glue dries. I’ve had relatively good success with this although on larger panels, along some of the joints, the boards would be a bit higher on one side of the joint and lower on the other which required sanding to even them out. I’d like to try to avoid as much of that as possible with the new table top although I know it won’t come out perfect and will require sanding. 

As an alternative to cauls, I’ve seen some videos where, after the boards are clamped, they use face clamps to align the boards and pocket hole screws to secure it until the glue dries. Some people removed the screws after the glue dried so they could reuse them, some people left them in. I do have a pocket hole jig and screws. My question is, has anyone used this technique and what kind of success or failure was it? I will be using pocket hole screws to help secure the maple/walnut edges since two of those edges will be gluing edge grain to end grain.

As always, thanks for your help.


----------



## Cherryville Chuck (Sep 28, 2010)

I can’t help with the screw question. I rarely use them. If I really wanted the glue up flat on one face I’d either spline (blind grooves if they aren’t supposed to show at the ends) or dowel. You could make a quick and easy dowel jig using some ply and wood scraps along with Lee Valley drill bushings. The jig would look like a T with the bushings in the leg. With the cross registered on the show face the holes would all be equidistant and the same distance from the faces. As for gluing to the end grain I would keep adding glue until the end grain stayed wet before I stuck it to edge or face grain.


----------



## DaninVan (Jan 1, 2012)

If I understand you correctly, Barry, you want to 'breadboard' trim onto solid lumber panels(?) ... "I will be replacing it with a walnut and maple top" .
There are species specific expansion/shrinkage tables for lumber planks, and even for the relatively stable ones it's still significant. the sidetrim isn't an issue; very little longitudinal movement, but the end grain over three ft. would have significant movement.
Gluing the end trim might be a serious problem down the road if not immediately. 
https://www.popularwoodworking.com/tricks/how-to-calculate-wood-shrinkage-and-expansion/
https://www.woodbin.com/calcs/shrinkulator/
Oh, and before Stick beats me to it,_ splines!_


----------



## DesertRatTom (Jul 3, 2012)

Blind splines will allow you to glue up the pieces while leaving the ends unaffected. Splines for the long grain side. The trick is to flatten and thickness your stock BEFORE you cut the grooves for the spline. Flatten the top either with a hand plane or a planer. Cut all the grooves with the flattened face down. This will help greatly on producing a flat glue up. Do the flattening, cut the spline, glue up and clamp on the same day. Wood can warp enough to be annoying in one day. Be very careful in selecting your stock. Quartersawn is your best bet for this kind of project. 

The grain of your splines should be cross grain, the grain should run perpendicular to the long pieces' grain. This means you will have to piece together the spline piece by piece. I'd thickness the spline material and match the grooves to the spline thickness so it's a snug fit. If you don't have a planer, you can use your table saw or band saw to resaw your spline pieces to the thickness you want. Then trim off short pieces for the spline. If you use your table saw to resaw, make sure your blade is exactly 90 degrees to the table. If you don't have a Wixey digital angle gauge, get one first. They're $30 on Amazon.

If the piece you're resawing for splines is 3/4, you can get two quarter inch wide pieces from each pass, and if the material is too wide to split in one pass, you can flip it over and resaw the other half. Try not to have the blade overlap the first cut on the second pass. This will allow you to cut at least a 5 inch wide board for splines.

You can use splines to attach a finished edge to the short ends. Make a nearly full length groove, but not all the way across, in other words, a blind groove. Remember, face side down on the router table, or face up if you're cutting the groove freehand. Place 3-4 splines here and there along the groove to allow a little freedom of movement for normal expansion and contraction. 

You can use pocket screws to hold the table pieces in place during glue up, but put the screws in through bottom side and use a cawl to hold the pieces firm, finished face down as you pocket screw them together. Once glue is set, you can remove the screws and even fill the holes. But you really don't need then since you're using splines for alignment, and everything cut flat face down will align pretty well.

This method will allow you to get a very flat table top that will require only a minimal amount of sanding to level. Finally, I'd consider using a scraper for a final pass to smooth out the top. Nothing looks better than the effect of a good finish on a scraper prepared table top.

Again, I'd go with quarter sawn wood for the long pieces. It costs more, but will be easier to get a great result. BTW, if your stock is 3/4 inch, your spline should be about a quarter inch thick. I love splines. Easy, strong, invisible, although a through spline with a different color between equal width glued up material can really look nice. One nice thing about a solid wood top, you can put a beautiful edge on it.

Hope this is helpful.


----------



## Barry747 (Jun 16, 2011)

Wow, I’m glad I posted this. I’m such an idiot. I was going to do a future post questioning how to attach the base since it’s screwed down on all four sides (as you might be able to see in the picture, 20 screws is a bit of overkill) and I was concerned about wood movement. It never occurred to me that the bigger problem would be the edge to end grain over the 33”. I used the calculator in Dan’s link and, using some assumptions since I don’t have the lumber yet, I came up with ¼”. I will be finishing the table top with Extreme Protection Polyurethane from Crystalac. I don’t know how much this will reduce the movement but I know it sure won’t be 0.

As both Tom and Charles suggested I’ll use blind splines to align the boards. I have a slot cutter for my router and, as you stated, if I route all of the slots with the boards face down on the router table all of the slots will be the same distance from the top of the boards so they should align quite well. Since I’m using the spline for alignment not for strength, I can cut a spline the full length of the slot so that the grain going in the same direction won’t make a difference. However, for the frame on the end grain sides I’ll do as Tom suggested and cut the slot full length but use cross grain splines at intervals. Does this make sense to you?

Tom, I always do as you suggested about prepping the wood. I buy rough cut lumber from the yard let it acclimate to the shop for a week or two then mill is slightly larger than finished dimensions. I let it sit overnight then mill it to final dimensions and glue it up. I learned this lesson the hard way early on in my woodworking. 

If I can ask you one more question since we’re on the topic it’s about attaching the base. First off, I’ll use two screws for each side not five. This is a coffee table and not built to withstand a nuclear attack. If I elongate the holes so that the elongation goes across the grain, and snug up but don’t firmly tighten the screws, do you think that will be enough to handle any expansion?

Once again, I want to thank you for your help. Without it, this project would have ended in disaster.


----------



## DesertRatTom (Jul 3, 2012)

Probably the simplist way is to use table top mounting brackets as shown in the picture. Cut a groove in the table frame and loosely attach the top with a short screw. There are other methods, but his one works great.


----------



## Knothead47 (Feb 10, 2010)

What DRT just said.


----------



## Biagio (Mar 2, 2013)

Hi Barry,
I used your proposed method for a vanity slab some 12 years ago. Used polyurethane glue and pocket hole screws, nothing has moved in that time. My end-grain length was about half of yours, but nothing has moved there either (but I was able to leave a "free" end at the non-visible splashback end). Probably because the wood was very well-seasoned up-cycled floorboards of a species formerly known as Rhodesian Teak Rhodesia is now Zimbabwe) not a teak as such, but a hard, splintery wood, used for railway sleepers before concrete took over. Sands to a very smooth finish.
I used clamps and caulk as well, although probably overkill. Did not remove the screws out of laziness.
At the time, I was not equipped to make splines, at least not safely. But I have since become interested in spline joinery thanks to Stick, Tom and others here, and was took Tom’s advice to watch the Mark Sommerfeld videos on spline-based cabinet-making, so might well use them if I were doing the job now.
Although I followed Tom’s good side down rule, the piece still needed a fair amount of sanding and scraping.
I turned the legs from laminated sections of the same wood, and beat the copper basin out of 1mm copper sheet.
If you zoom in on the images, you will see the joints are all tight, in spite of noxious potions my adored wife might have spilt onto the surface.


----------



## Stick486 (Jan 4, 2013)

Biagio said:


> Although I followed Tom’s good side down rule, the piece still needed a fair amount of sanding and scraping.



it's good side up for free hand and good side down for the RT......
the splines do a great job of/for aligning for a flush surface...

.


----------



## DaninVan (Jan 1, 2012)

Biagio; that vanity is beautiful! I hate seeing wood around water but yours seems to be holding up extremely well. Great job!


----------



## Barry747 (Jun 16, 2011)

Tom, I’ve seen that before but, since my base is wrought iron I initially dismissed the idea. But somehow it stuck in the back of my mind, what’s left of it, and then the simple answer came to me. All I have to do is attach a wood frame to the top of the wrought iron, cut a groove all around it, and connect the top to the frame using those connectors. I’ve been mulling around how to do that for weeks. Thank you!

Biagio, that is an absolutely beautiful piece of work. Very well done. Did you turn the legs too? I’m not a turner but I can appreciate turned pieces having seen it done and the work that goes into it.

I’m now considering three ideas of how to join the 6 boards. First, the original idea of using pocket hole screws until the glue dries. Second, the popular idea here of using splines, which I will use to attach the edges to the end grain sides. And, a third way that I just thought of. How about tongue and groove? That’s how they make flooring. I’d have to buy the bits but, in the long run, would that be easier than cutting the grooves and all of the spline pieces, not to mention stronger? Oh, wait, I just mentioned stronger. Anyway, have any of you used tongue and groove joinery and if so, how difficult was it to get it right?

Stick, thanks for the info. I've read that before when you posted it for other members questions. I consider you the encyclopedia of RouterForums. Has anyone ever stumped you with a question?


----------



## DaninVan (Jan 1, 2012)

Barry; nothing wrong with T&G but you're over thinking this; glued splines are _incredibly strong_!
Way easier and no new tools to buy...OK, that may not be a selling point. 
If you're doing blind splines, and no reason to if you're adding end trim, just use 1/4" plywood for your splines. Nobody will ever see them and grain direction is no longer an issue (for the splines, not the planks),
and if you're clamping the whole assembly anyway, why do you need the pocket screws? 
Using the cawls is just the right thing to do; you don't want to introduce a bow into the assembly from the clamping pressure.
Just make the spline slots deep enough that there's plenty of glued surface...and make the slots a tich deeper than the ripped width of your splines! You don't want the splines to prevent the plank gap from fully closing


----------



## Stick486 (Jan 4, 2013)

Barry747 said:


> And, a third way that I just thought of. How about tongue and groove? That’s how they make flooring.
> 
> Has anyone ever stumped you with a question?


the T&G joint is sized (sloppy) to allow for wood movement, it's shallow (¼'') and doesn't stayed glued up for long..

Stumped??? all the time...


----------



## Stick486 (Jan 4, 2013)

Stick486 said:


> the T&G joint is sized (sloppy) to allow for wood movement, it's shallow (¼'') and doesn't stayed glued up for long..


no real strength either...
see...

.


----------



## Biagio (Mar 2, 2013)

DaninVan said:


> Biagio; that vanity is beautiful! I hate seeing wood around water but yours seems to be holding up extremely well. Great job!


Thanks, Dan. The piece was given multiple coats of polyurethane marine varnish on all surfaces, including the underside. The finish has laughed off water, but took some strain from nail polish remover, hair remover and other chemicals that women apply to themselves, but that we would hesitate to apply as paint strippers or rust removers.
My first wooden vanity was built in 1993. Imbuia - now a protected species, and costs the earth - at least around here. Simple edge-to-edge gluing, same polyurethane glue, same finish. I had not discovered cope-and-stick bits at the time, so the cabinet doors were made with routered M&T joints. At the time, I found some Imbuia-faced plywood for the panels. Made the tenons and mortises too deep, so that the tenons suddenly showed through when I undercut the lip for the doors.
Interestingly, the oil in the wood reacted with the marine varnish to form tiny bubbles, and because it was hot weather, the varnish started setting before the bubbles could break the surface. No amount of thining helped. After several sandings down and re-finishing, visits from supplier experts, etc, I just acceoted it as "hand-crafted slight flaws".


----------



## Cherryville Chuck (Sep 28, 2010)

I normally use the same fasteners that Tom showed but Lee Valley also sells elongated steel washers that will work. They are a Christian Becksvoort design. They allow movement between the head of the screw and the washer.


----------



## Barry747 (Jun 16, 2011)

Yep, you're all right. I'll go with splines the entire length and, Dan, you answered my next question which was, can I use 1/4" plywood for the spline The good thing about 1/4" plywood is that it's true to size, not undersized like thicker plywood. I ordered a 1/4" slot cutter this morning since the one I have for biscuits is the wrong size. I already have the arbor and various size bearings so I just need the cutter. 

I also realized that attaching the top is much simpler than putting a frame over the wrought iron base. Adding the frame would also raise the table higher than we want it. The top of the base has a flange all around it. See the picture in post #5. All I have to do is screw what I call the Z shaped fastener to the table top in such a way that the bottom piece of the fastener, rather than going into a grove, goes under the flange. I may have to reshape the fasteners so that they are snug up to the bottom of the flange.

If anyone has any other suggestions please post them, otherwise I'm good to go as soon as I get the lumber. I have a call into the lumber yard to see if they've gotten a shipment of better quality walnut.

Again, thanks for everyone's help. I really would have screwed this up without you.


----------



## Stick486 (Jan 4, 2013)

on those plywood splines..
use Baltic Birch...
trust us on this one...


----------



## Stick486 (Jan 4, 2013)

Biagio said:


> s.
> Interestingly, the oil in the wood reacted with the marine varnish to form tiny bubbles, and because it was hot weather, the varnish started setting before the bubbles could break the surface. No amount of thining helped. After several sandings down and re-finishing, visits from supplier experts, etc, I just acceoted it as "hand-crafted slight flaws".


next time...
use a scraper on the bubbles and not sandpaper...


----------



## DaninVan (Jan 1, 2012)

Barry; " I really would have* screwed this up* without you."
Heh...good one!


----------



## Stick486 (Jan 4, 2013)

DaninVan said:


> 1... If you're doing blind splines, and no reason to if you're adding end trim, just use 1/4" plywood for your splines. Nobody will ever see them and grain direction is no longer an issue (for the splines, not the planks),
> 
> 2... and if you're clamping the whole assembly anyway, why do you need the pocket screws?
> 
> ...


1... Baltic Birch for the plywood splines or go home... trust us on this....

2... exactly..

3... pipe clamps are even better w/ wedges (shake shims) for finite bow control....
if you get bowing.....
too much clamp pressure and/or the edges aren't mated...

4... 9/16 deep slots w/ 1'' wide splines...
the splines should fit nicely to a fuzz loose to allow for glue to limit squeeze out....


----------



## DaninVan (Jan 1, 2012)

#3....great idea; thanks for that! Although I think you might have meant cedar _shingle_ shims(?); shakes can be fairly irregular, and can also be pretty thick at the butt.


----------



## Biagio (Mar 2, 2013)

Stick486 said:


> next time...
> use a scraper on the bubbles and not sandpaper...


Thanks Stick, will bear that in mind, I have a nice imbuia counter-top in the loft, waiting for a project.
I must confess I was stumped by the problem - the doors were fine, the mirror frame was fine, only the top gave problems. I later read that it was due to the type of oil in imbuia. I guess my boards were from different trees. I had also not had any problems with a bookcase I finished with Danish oil, so it all rattled me a bit. The supplier’s experts had no solution, but gave me a free 5 liters of the marine varnish.


----------



## DaninVan (Jan 1, 2012)

Perhaps wiping it down with alcohol or acetone before applying the poly?
Maybe worth trying on a test piece?


----------



## Stick486 (Jan 4, 2013)

Biagio said:


> Thanks Stick, will bear that in mind, I have a nice imbuia counter-top in the loft, waiting for a project.
> I must confess I was stumped by the problem - the doors were fine, the mirror frame was fine, only the top gave problems. I later read that it was due to the type of oil in imbuia. I guess my boards were from different trees. I had also not had any problems with a bookcase I finished with Danish oil, so it all rattled me a bit. The supplier’s experts had no solution, but gave me a free 5 liters of the marine varnish.


treat the wood the same as you would an oily tropical wood glue up before you apply the finish...

.


----------



## Stick486 (Jan 4, 2013)

DaninVan said:


> Perhaps wiping it down with alcohol or acetone before applying the poly?
> Maybe worth trying on a test piece?


or the bottom side...


----------



## Cherryville Chuck (Sep 28, 2010)

Stick486 said:


> 3... pipe clamps are even better w/ wedges (shake shims) for finite bow control....
> if you get bowing.....
> too much clamp pressure and/or the edges aren't mated...


It also helps to alternate clamps on top and bottom of a glue up.


----------



## Barry747 (Jun 16, 2011)

Dan, ha, I didn't even realize the pun until you pointed it out. Pretty good, actually.

Stick, yes, I'm using the 1/4 Baltic Birch plywood for all of the splines. I expect the cutter to come in tomorrow. I'll test it out on some scrap, of which I have a lot, to make sure that there is room for the glue all around the spline and that I don't bottom out the spline on either board.

Dan, Stick, Charles, yes, I have 4 of the Rockler Sure Foot Clamps and 4 pipe clamps. I use packaging tape on all of the clamp surfaces that will touch the panel. I'll use the Sure foot clamps on the bottom and alternate them with the pipe clamps on the top. I never thought of the obvious until you pointed it out. I'm talking about using shims under the bar clamps on any joints that aren't flat. I use shims with my thickness planner sometimes when I have a board that has a slight warp to level it before running it through the planner. I now know to use it with the clamps. And, yes, once again, with the shims there is no reason to use pocket screws. 

Biagio, stick's suggestion of a card scrapper is a good one. Personally, I struggle to get a good edge on my scrappers. I've watched many videos and a number of documents on how to do it. That's just one of those things that I'm brain dead with. However, when I accidentally get the right burr it's a really great tool, especially with highly figured wood or wild grain. It also leaves a much smoother surface than with sandpaper. For the table I mentioned when I started this thread, I finally was able to go to the lumber yard today. They got a shipment of 600 bf of 8/4 black walnut so I was able to get a couple of boards for the table. I also picked up a 4/4 birds eye maple board that also exhibits some nice curl. To smooth that out I'll beat the heck out of a card scrapper until I get it right. That's one of the types of wood that card scrappers work well on.


----------



## Stick486 (Jan 4, 2013)

DaninVan said:


> #3....great idea; thanks for that! Although I think you might have meant cedar _shingle_ shims(?); shakes can be fairly irregular, and can also be pretty thick at the butt.


no...
I meant shakes.. not cedar shims...


----------



## DaninVan (Jan 1, 2012)

Resawn shakes?! Or the simple split ones? Nope. I see no advantage over cedar shingles that'd make me go down that road...
If you buy the shim pkg. rather than the full bundle of shingles it'll be a LOT less expensive than either the bundled shingles _or_ shakes.
A full bundle of either will last a loooong time.
And if anyone is buying a bundle of cedar shingles, _buy the lower grades_*; it'll also save you a 'bundle'. 

*you don't really need a clear #1 grade
Grading and Manufacturing | Products | Cedar Shake and Shingle Bureau


----------



## DesertRatTom (Jul 3, 2012)

Really good and useful discussion!


----------



## thomas1389 (Jan 4, 2012)

Biagio, that is one beautiful vanity.


----------



## Stick486 (Jan 4, 2013)

DaninVan said:


> Resawn shakes?! Or the simple split ones? Nope. I see no advantage over cedar shingles that'd make me go down that road...
> If you buy the shim pkg. rather than the full bundle of shingles it'll be a LOT less expensive than either the bundled shingles _or_ shakes.
> A full bundle of either will last a loooong time.
> And if anyone is buying a bundle of cedar shingles, _buy the lower grades_*; it'll also save you a 'bundle'.
> ...


resawn..
those shingles are outlawed here...
a bundle is usually about free... less than a bundle of shims..


----------



## DaninVan (Jan 1, 2012)

The wildfire fire issue? 
To be fair, with the skyrocketing cost of Cedar products here and everywhere else, metal roofing has really taken off. Probably the right way to go.
Are all exterior Cedar products banned? I think I knew about the shingle thing happening in California.


----------



## Stick486 (Jan 4, 2013)

yes..
metal for that know better...
pretty much..


----------



## Biagio (Mar 2, 2013)

DaninVan said:


> Perhaps wiping it down with alcohol or acetone before applying the poly?
> Maybe worth trying on a test piece?


Dan, I did try that at the time, made no difference. I subsequently read the article Stick posted - Eric Meier advocates using several coats of shellac as a sealant before applying the polyurethane.


----------



## Biagio (Mar 2, 2013)

thomas1389 said:


> Biagio, that is one beautiful vanity.


Thanks Thomas. I would love to say it was all planned, but it kind of took on a life of its own. I originally wanted to make the bowl out of wood as well - I still have a mental picture of a photo of a stunning pear wood vanity on some billionaire ‘s yatch, but I lost my nerve at the thought of all the laminations, so made a copper bowl instead. It started out as a rectangular top, with a plain skirt on three sides. The cut-off corners were added to reflect the pentagonal shower and corner bathtub, and the double bead edging was added to pick out the shape of the tile listello. 
When we eventually downsize, it is coming with us.
Some day I still want to make an all-wood vanity.


----------



## Biagio (Mar 2, 2013)

Barry747 said:


> Biagio, stick's suggestion of a card scrapper is a good one. Personally, I struggle to get a good edge on my scrappers. I've watched many videos and a number of documents on how to do it. That's just one of those things that I'm brain dead with. However, when I accidentally get the right burr it's a really great tool, especially with highly figured wood or wild grain. It also leaves a much smoother surface than with sandpaper. For the table I mentioned when I started this thread, I finally was able to go to the lumber yard today. They got a shipment of 600 bf of 8/4 black walnut so I was able to get a couple of boards for the table. I also picked up a 4/4 birds eye maple board that also exhibits some nice curl. To smooth that out I'll beat the heck out of a card scrapper until I get it right. That's one of the types of wood that card scrappers work well on.


Barry, at the time I had no idea what scraping was about - I tried some ineffectual dust-creation with a flexible paint scraping blade, and gave up. Only recently have I got the hang of actually producing shavings with a decent steel scraper, and have become a convert. Have now gone the whole hog, with some Crown, Narex and LV scrapers, a LV scraper holder (I can highly recommend it) and a LV burnisher for straight scrapers. Have not had occasion to try the profile scrapers yet.
Earlier this year, I wanted a cabinet for my medical instruments. Started out as something with plain black drawer fronts, but then I remembered a board of birds-eye that had been in the loft for 30 years, turned out to be just enough. Sanded and scraped, and finished according to some advice I found on the net: three coats of boiled linseed oil (to pop the grain), allowed to cure for 5 days per coat, sanded to 600 or 800 between coats, followed by three coats of poly. Marvelous deep, lustrous finish, and the color has been maturing ever since.
You can see the reflection of the handles in the gloss. Incidentally, drawers made from up-cycled red mercantile shelving (I think it is called lauan n your part of the world), dovetails made with an MDF jig from a Stottman template (unsung American inventor). Apologies for rotated images- no idea of the aetiology.


----------



## Cherryville Chuck (Sep 28, 2010)

DaninVan said:


> The wildfire fire issue?
> To be fair, with the skyrocketing cost of Cedar products here and everywhere else, metal roofing has really taken off. Probably the right way to go.
> Are all exterior Cedar products banned? I think I knew about the shingle thing happening in California.


Texas too. Me and a buddy about 40 years ago made split cedar pickets for picket fences which we sold to McGillis and Gibbs, a power pole maker. They finally quit buying because the main markets at the time, Texas and California, banned them because they were too flammable.


----------



## Barry747 (Jun 16, 2011)

Biagio, that is a beautiful piece. Your use of the contrasting woods is well done. I live in Florida and work in a garage without air conditioning. Due to the extreme humidity during the summer, one of the things that I have to stay ahead of is rust. Besides the usual suspects of cast iron surfaces, I found rust on my card scrappers. I saw an advertisement for a whole assortment of card scrappers in various sizes and made from several different materials. I decided to get some scrappers made of stainless steel. http://www.tgiag.com Needless to say, I haven't had any trouble with corrosion on those. Of course, I struggle with those also to get a proper burr. Oh well, back to the file and burnisher for another round of frustration. I just restored a 50 year old Stanley #4 hand plane and it came out great. Card scrappers, not so much. Gotta be a mental block. 

Anyway, keep on turning out your beautiful pieces and post them to the Forum.


----------

