pocket screws

[RFGuy]

I have never tried pocket hole joints before, but I am not opposed to trying them. One question that I had is how strong are they for plywood where you attach two pieces at 90°? Say you have a cabinet carcass and you are attaching the back to the top, so end grain to face frame. I see them used for this on projects online and always wondered how strong this was in reality. My concern is the fact you would be drilling diagonally into the face frame through to the end grain. Isn't tearout and possible plywood delamination a concern here? Does it work well on 3/4" but not so well for 1/2" because of this, or are my concerns not valid? For solid wood, I expect the joint to be strong, but it seems to me that plywood at 90° may not hold that well. Just asking to try to understand since I have no experience with them.

Answering my own question, since I found some answers on another forum. Most of my questions wrt using them on 1/2" plywood was answered at the link below. Any opinions on the new pocket hole jig from Armor Tool, or is everyone a Kreg devotee?

Can I use Pocket Holes in 1/2" plywood?
https://sawmillcreek.org/showthread.php ... ot-plywood

Armor Tool Jig:
https://armor-tool.com/products/woodwor ... gLmC_D_BwE

[BuckeyeDennis]

I know reible uses them, who else? Do you like/dislike them, pro and cons.

I was introduced to them a few days ago and I like the speed and strength of the joints we got with them making some quick cabinet carcasses I made for a friend's shop.

So far I am kind of impressed. He was telling me that the Shakers actually invented the joint and used them as far back as the early 1800's.

What say you?

Thanks in advance!

If you don't have pocket-hole equipment, then by all means get some. When it comes to screwing components together, it's usually the slickest way to do it. But I mostly use pocket screws on quick & dirty utilitarian-type projects.

For joining sheet goods, I'm a big fan of "rabbet and dado" joints (aka “tongue & dado” and “locking rabbet”). For me, making them is generally faster than drilling a bunch of pocket holes and then driving screws. But what I really like about rabbet and dado joints is that they make the components self-jigging for assembly. No futzing around trying to keep the edges aligned while driving screws. I just apply the glue, mate the parts, pop in a few pin nails to hold them while the glue dries, and move on.

Rabbet & dado.jpg (13.54 KiB) Viewed 11739 times

In plywood, about half of the glue surface is long-grain to long-grain, giving a good strong bond. More info and instructions for making the joint can be found at https://www.aconcordcarpenter.com/tongu ... joint.html.

[sehast]

I will just add that I really like these screws for all types of wood joining, not just pockets especially in solid wood. Their ability to auger into the wood without splitting it makes for a quick strong hold.

[RFGuy]

I will just add that I really like these screws for all types of wood joining, not just pockets especially in solid wood. Their ability to auger into the wood without splitting it makes for a quick strong hold.

Thanks Steve. That definitely helps me understand better. I have never used them, but I know a lot of people use these with great success. It makes more sense to me now knowing that part of their success comes from have a specific screw profile that minimizes tearout particularly for plywood.

[rjent]

I know reible uses them, who else? Do you like/dislike them, pro and cons.

I was introduced to them a few days ago and I like the speed and strength of the joints we got with them making some quick cabinet carcasses I made for a friend's shop.

So far I am kind of impressed. He was telling me that the Shakers actually invented the joint and used them as far back as the early 1800's.

What say you?

Thanks in advance!

If you don't have pocket-hole equipment, then by all means get some. When it comes to screwing components together, it's usually the slickest way to do it. But I mostly use pocket screws on quick & dirty utilitarian-type projects.

For joining sheet goods, I'm a big fan of "rabbet and dado" joints (aka “tongue & dado” and “locking rabbet”). For me, making them is generally faster than drilling a bunch of pocket holes and then driving screws. But what I really like about rabbet and dado joints is that they make the components self-jigging for assembly. No futzing around trying to keep the edges aligned while driving screws. I just apply the glue, mate the parts, pop in a few pin nails to hold them while the glue dries, and move on.

Rabbet & dado.jpg

In plywood, about half of the glue surface is long-grain to long-grain, giving a good strong bond. More info and instructions for making the joint can be found at https://www.aconcordcarpenter.com/tongu ... joint.html.

Hey brother! That is my goto and favorite joint for a lot of things. I agree, lots of holding power with glue, Ron just amazed me with the speed and strength of a carcass we built in my shop. Still kind of reeling from the experience LOL.

I have some small projects coming up (putting off again my wife's kitchen ) making some HO train rolling stock cases. I plan on using PS to build them. I will report back ....

Again, thanks everyone!

[edflorence]

I have used them...They are great for certain uses, like the joint between a case side and a top. But do they compare in strength to more traditional joinery? Check out this page:

https://woodgears.ca/joint_strength/pockethole.html

Comparing time spent to make a joint, pocket screws seem much faster than mortice and tenon, but when compared to dowels, not so much.

Anyway, interesting reading.

[RFGuy]

I have used them...They are great for certain uses, like the joint between a case side and a top. But do they compare in strength to more traditional joinery? Check out this page:

https://woodgears.ca/joint_strength/pockethole.html

Comparing time spent to make a joint, pocket screws seem much faster than mortice and tenon, but when compared to dowels, not so much.

Anyway, interesting reading.

Thanks Ed. Matthias' testing is definitely interesting. Just scanning YouTube, there really isn't a lot of joint testing that I can find for pocket screws (lots of videos though on wood glue strength testing). I found these couple of videos helpful. Both seem to use more pocket screws than Mathias for his small joint tests. Without professional equipment to do this testing, I think all of them did a decent job of capturing the performance of the various joint strengths. In summary, pocket screws seem to be about half as strong as M&T joints. So, if absolute strength is needed M&T is a clear winner, but the real question is how much strength is needed for a given application? Also, for cabinet carcasses, noone is going to do M&T joinery (unless they own a Festool Domino), but I wonder how pocket screws compare in joint strength to the rabbet and dado approach like BuckeyeDennis uses? I would have to think the rabbet and dado approach would win out for sure. Pocket screws do appear to be a good bit stronger than biscuits based on the testing in this one video and in the other video they were strong enough to hold a car on a ramp. Granted that was one beefy ramp they built AND a lot of pocket screw joints, but it still held. Bottomline, I think for pocket screws it comes down to speed of making the joint versus joint strength. You are giving up a bit of strength for a much faster execution, but that may be acceptable for a given application.

It seems like certain things in woodworking follow fads/trends like everything else in society. I wonder if this rediscovery of pocket screws in the general woodworking community is part of that (fueled by manufacturers wanting to sell tools and pushing said tools on social media). Will pocket screws go out of style again in a few years? I mean, I know biscuit joinery definitely peaked in the '90s I think due to Norm evangelizing it on the New Yankee Workshop. Epoxy filled tables, aka river tables, peaked on Youtube about a year ago and hopefully are going out of style now. Hand tool joinery, e.g. handcut dovetails, making everything with saws, planes and chisels seems to be going through some kind of resurgence. In fact, I stopped going to my local woodworking group meetings because they tended to shun those of us that still use power tools to make woodworking. I am neither pro nor con on pocket screws, but I do find them interesting and will likely try them out someday...just wondering where in the trend I am at. It seems like this new trend on pocket screws started around about 2011 (if Google Analytics can be trusted - ). By the time I get around to it, they may be out of style again!!!

[youtube]https://www.youtube.com/watch?v=6cAUz_eCmbw[/youtube]

[youtube]https://www.youtube.com/watch?v=Ahb9RUf6wtg[/youtube]

Pocket Screws Trend on Google:

GooglePocketScrews.jpg (57.29 KiB) Viewed 11640 times

Pocket Screws Trend on YouTube:

YouTubePocketScrews.jpg (56.64 KiB) Viewed 11640 times

[sehast]

That was an interesting joint test video. Kind of confirmed my beliefs that mortise & tendon joints and dowel joints are strongest and I think if they would have tested floating tendons (dominos) similar results would have been seen. I feel these three joints are basically equivalent in strength as shown in the tests when using 1 inch penetrations. While pocket screws are usually good enough for most applications they are a long way from the strength of these three other joints. Ease of implementation also is important, at least for me. Mortise and tendons are by far the most time consuming. I think dowels (if you have a good jig like Jessem) are slightly easier than or at least equivalent to pocket screws but slightly more difficult than floating tendons (dominos). That is the reason I have gravitated to dowels when strength and/or appearance are a concern. Dominos would be nice but it is hard to justify the cost of the tool.

[RFGuy]

That was an interesting joint test video. Kind of confirmed my beliefs that mortise & tendon joints and dowel joints are strongest and I think if they would have tested floating tendons (dominos) similar results would have been seen. I feel these three joints are basically equivalent in strength as shown in the tests when using 1 inch penetrations. While pocket screws are usually good enough for most applications they are a long way from the strength of these three other joints. Ease of implementation also is important, at least for me. Mortise and tendons are by far the most time consuming. I think dowels (if you have a good jig like Jessem) are slightly easier than or at least equivalent to pocket screws but slightly more difficult than floating tendons (dominos). That is the reason I have gravitated to dowels when strength and/or appearance are a concern. Dominos would be nice but it is hard to justify the cost of the tool.

Yeah, I don't know how accurate these tests are because I am sure there are quite a few variables that are not being taken into account such as wood variation, already existing stress cracks in the wood, glue vs. no glue, making the most optimal joint of each type for comparison, etc., etc. Still, I think these videos give us some idea of how strong these joints are relative to each other. Here is another video where actually the Domino (loose tenon joint) came out on top of all other joints...and not by a little, but by a lot. Still, I am not sure of his test methodology, e.g. he did some joints in softwood and some in hardwood so it seems to be comparing apples to oranges. You need to make all the joints in the same wood to try to compare them.

Personally, I have always loved dowel joinery. I own the Jessem Dowel Jig which is awesome and makes them easy. However, I read this article that talks about how round tenons deform and become ovals resulting in weak joints with time, so I don't know what to believe anymore. After awhile, you start splitting hairs and can easily over-analyze this stuff.

DowelJoints.pdf

(626.93 KiB) Downloaded 1500 times

[youtube]https://www.youtube.com/watch?v=xfjg3eQxlnw[/youtube]

[bainin]

i use them occasionally for cabinet type stuff. My router table build from a few months back used them. They are fast and positionally agnostic...can place them just about anywhere so long as they provide the support you need.

The issues I have with them are :

1) Sometimes the screw doesn't set correctly to align with the pre-drilled hole. Then when you drive the screw in-the clearances are small enough that you can get the screw point popping thru your second piece. Keep a file handy

Its hard to tell visually if you have the screw placed properly in the pre-drilled hole to avoid this.


2) I'm sure there are valid reasons for forcing me to keep the special screw head adapter for my drill - but I'm constantly worried I will lose it. Not sure I see a good reason why these screws couldn't simply use a philips head.


b