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Pocket Hole Problems

4K views 36 replies 19 participants last post by  wmgworks 
#1 · (Edited by Moderator)
I'm trying to build a set of saw horses. All 2×4 construction. One side of the set of legs is attached to he stretcher by pocket holes.. The other leg is attached to that leg via a hinge so they can fold up. Legs are mitered at 19 deg. The problem I'm having is the pocket screws do not seem to be grabbing the material correctly. This is my first time using pocket holes so I'm sure I'm doing something wrong here. I set the depth of the drill bit to 1 1/2" (the max on the K4) and the height of the holes to 1 1/2" (the max). I'm using coarse 2 1/1" kreg screws. On the end opposite this one, I actually pushed the screw through the stretcher a tiny bit. In this picture it shows that the unthreaded part has pushed through the leg. What am I doing wrong here?
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#5 · (Edited by Moderator)
Are you overdriving the screws? Meaning - countersinking them past the depth stop of the pocket because the torque of the driver is set too high? Also, the joint needs to be clamped before the screw is applied or it will push the opposing member out of alignment.

I don't agree with the assessments that pocket hole joinery is "just not strong" or "one of the weakest joinery methods", especially coupled with glue. However, though the other methods of joinery are stronger, they too are not always appropriate just as pocket holes aren't always appropriate. M&T doesn't work very well with plywood and other materials, where screws and glue excel.

Edit: The video was done well. Just wondering why the person who did the testing didn't use glue with the pocket hole joints. That would probably make for a much better comparison. No arguing the other methods aren't stronger. That's an accepted principle.
 
#6 ·
Pocket screws are neither the second coming or El Diablo.

They are great in a production environment (with a machine, not jig) for face frames.

But as stated above, with saw horses glue it and screw it and forget it. I dont see pocket screws/holes buying a thing.

Face frames are about as fast and stronger if you have a boring machine.

Sorry to get off topic there.

Steve
Who has made more than his share of pocket holes and dowel holes, and if he believed voting made any difference would cast his for dowels.
Vote Dowels: Its for the children.
 
#7 ·
Here is the video of Steve Ramsey making them so I know the pocket hole screws will work for this.

http://woodworking.formeremortals.net/2014/06/build-a-folding-sawhorse/

I watched Steve put these things in over and over and over. All he does is prop the leg on his shoulder for support and screw it down into the cross member. I didn't see him use any clamps or glue.

It's entirely possible I overdrove the screws I guess. I'm also just starting to use an impact driver for the first time. How deep into the pocket hole should the head of the screw be?
 
#8 ·
For those of you that complain about poor joints with pocket hole sccews,,,I don't think you have given them a fair shake. I use them for all sorts of stuff. The screws used by themselves hold really well.

I think the OP just needs to improve his technique. After all, it is his first time. It will get better.
 
#9 ·
Pocket screws are neither the second coming or El Diablo.

They are great in a production environment (with a machine, not jig) for face frames.

But as stated above, with saw horses glue it and screw it and forget it. I dont see pocket screws/holes buying a thing.

...

- SirIrb
I think the reason he used Pocket holes maybe was to hide the screws underneath so you have less of a chance of hitting them with a saw blade. Not necessarily for a stronger joint (my guess). I saw this video a long time ago and was planning on just countersinking screws from the cross member into the legs instead of the other way around because I didn't have a pocket hole jig at the time. Then one was generously gifted to me so I moved forward with the original concept.
 
#10 ·
I disagree with pocket holes not being strong also. Different joinery works for different projects. It looks like maybe to much torque is being applied and the screws are being driven in too far. If you have the holes set 1-1/2" from from the edge and you are seeing that much of the smooth shank, that has to be whats happening.

On a side note, and I know you are pressed for space in your shop, but these are some quick, down and dirty sawhorses that work great. I just built a pair this morning: Sawhorses
 
#11 ·
For those of you that complain about poor joints with pocket hole sccews,,,I don t think you have given them a fair shake. I use them for all sorts of stuff. The screws used by themselves hold really well.

I think the OP just needs to improve his technique. After all, it is his first time. It will get better.

- MT_Stringer
Thanks, Mike. That's my thought, too. After I had this failure I went back to the Mere Mortals community threads on the build and saw no one else having this complaint. So I was pretty sure it was something I was doing. I'm not going to go to pocket hole screws every time Just Because. I'd like to make this work because i know it should, though.
 
#12 ·
I disagree with pocket holes not being strong also. Different joinery works for different projects. It looks like maybe to much torque is being applied and the screws are being driven in too far. If you have the holes set 1-1/2" from from the edge and you are seeing that much of the smooth shank, that has to be whats happening.

On a side note, and I know you are pressed for space in your shop, but these are some quick, down and dirty sawhorses that work great. I just built a pair this morning: Sawhorses

- Reaperwoodworks
I think I ended up pushing them too far, too. But I kept pushing them because they didn't feel like they were grabbing the cross member. There was always a little gap there. How far should the head of the screw be inside of the pocket hole?

I watched Jay's video as well. Those are probably much easier to build than these. I really dig the way the one's I am doing fold up, though.
 
#13 ·
I think I ended up pushing them too far, too. But I kept pushing them because they didn t feel like they were grabbing the cross member. There was always a little gap there. How far should the head of the screw be inside of the pocket hole?

I watched Jay s video as well. Those are probably much easier to build than these. I really dig the way the one s I am doing fold up, though.

- wmgworks
When using pocket holes, the two pieces need to be clamped/held together before driving the screw. They do not pull the joint together.
 
#14 ·
Yeah, clamping them together will do wonders for keeping them aligned, flush, and setting the screws properly. Used properly… pocket holes can make strong joints. Maybe not heirloom or extra points for being fancy, but easy and certainly have a place.
 
#17 ·
Great advice everyone, thanks. I don't own a right angle clamp, or any other Kreg type clamps. All I have are bar clamps. Any suggestions on clamping it up?

@RedOak49 I'll give the drill driver a try next time.

I have materials to build a second sawhorse so I'll try all of these ideas on the second go around
 
#20 ·
If you are using the Kreg jig for your pocket holes, remember to set the depth on the jig to the thickness of the material you are drilling in to, and the length of the drill stop to the length of the screw you are using.

It is set up so that the unthreaded shaft of the screw is just at the end of the board you drill the pocket in. That way it will have some power to pull the joint together. It looks to me like you are drilling the pocket too deep.

-Brian
 
#22 ·
If you are using the Kreg jig for your pocket holes, remember to set the depth on the jig to the thickness of the material you are drilling in to, and the length of the drill stop to the length of the screw you are using.

It is set up so that the unthreaded shaft of the screw is just at the end of the board you drill the pocket in. That way it will have some power to pull the joint together. It looks to me like you are drilling the pocket too deep.

-Brian

- bbasiaga
All materials are 2×4. The highest the k4 model goes up to is 1 1/2" for material or screws. I read around and figured I should use 2 1/2" screws for what I was doing. Does that sound right? I'm leaning towards 'I pushed it too far' as the problem.
 
#24 ·
All materials are 2×4. The highest the k4 model goes up to is 1 1/2" for material or screws. I read around and figured I should use 2 1/2" screws for what I was doing. Does that sound right? I m leaning towards I pushed it too far as the problem.

- wmgworks
I think you've just figured it out. You're drilling a hole for a 1 1/2" screw and then using a 2 1/2" screws. The longer screws are going to have more un-threaded shank so it's coming through.

Since you are trying longer screws, I assume your are trying to get the screw to go deeper into the piece it's screwing into. While you could not drill as deep, you can only go so far before the head won't go below the surface.

In that case the hole really needs to be moved further back from the edge. Just as the Kreg guide would do. But then the screw won't exit the wood in the center. I.E., wood is still 1 1/2" think but you are drilling as if the material were 2 1/2" thick.

If you really want to use something longer than the 1 1/2", maybe just try 2" and not drill quite as deep.

As far as clamping, if you really, really want exact alignment, things have to be clamped really tight. The screw is pulling pieces at an angle. So as it pulls them together, it makes them slide across each other and out of alignment. So either it has to be clamped really tight, so the screw cannot pull it any tighter (really hard do do), or you have to set the initial position a bit off to anticipate the movement. Then the screws pulls it tighter and into alignment.

All that being said, these are saw horses and not fine furniture. Exact alignment isn't critical. And as others said, I'd throw some glue in the joint, even though the glue joint is pretty much just a but joint. Some glue is still adding some strength.
 
#26 · (Edited by Moderator)
The screws are quite large. larger than normal pocket screws.

It is not holding up a 4k lb car. it is holding up a fraction of the weight.

Did he make a strong joint? yes. Did he compare it to any other?-no.

So is this a strong joint?-yes. is a real pocket hole a strong joint?-yes. But apples for apples this video doesnt really prove anything. He doesnt compare it to M&T or Dowels. At the end of the day any of the listed joints would have held a fraction of the car. He was able to modify the concept of the pocket hole so that it held a fraction of a car.

Not sold.

I could have driven 4- 1/2" dowels through each side and held a fraction of a car.

I dont hate pocket holes. They have their place. As I said above I have used them tons to slap together faceframes. They work good for that.

I see pocket holes like beards. I have had a beard for 20 years but it just became cool to grow one in the last 2 years. Pocket holes are like beards. And soon everyone will start shaving and get the new look and people will sell their pocket hole jig for the new thing and everything will fall back to its rightful place: people will use pocket holes in limited places where they work well and make other, better options for other places.

EDIT:
I submit for you to ponder the amazing Bizkut Joiner and beards. Norm leading the charge, backed by some large companies, made everyone [hangs head in shame] including me think they must have this tool to make any joint.

[Everyone shaves their beard]

How about a pocket hole?

I will give them this: Pocket holes are far better than Bizkuts but their overuse has caused a fad.

EDIT 2:
Loose tennons.

[same as above]

Its what rwe2156 said, pocket holes are just not strong. A mortise and Tenon or some other joint would work.



- Will Merrit

I disagree… and so does this video

- InstantSiv
 
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