Moderators: Random Orbital Bob, nev, Noel, Charley, CHJ

 Reply
By shed9
#1197254
Distinterior wrote:I've used these http://www.axminster.co.uk/ujk-technolo ... d-ax884993

I am getting low on these myself but would be happy to order more from Axminster.


They often sell the UJK screws cheaper in the Axi shop itself near the POS/exit. Bit like the chocolates at a Tesco aisle.
By Mark A
#1197280
In the past I've used normal countersunk wood screws with a small washer under the head. Not the most elegant approach, but it was only for a jig.

Sent from my Moto G (4) using Tapatalk
User avatar
By Eric The Viking
#1197290
lastminute wrote:...are plasterboard screws worth trying?


Taking the question literally, then yes!

They have a trumpet-shaped head, flat at the edge, as they are designed to pull slightly into plasterboard, but...

... to get a pocket hole joint to pull up properly you need the right tension, meaning in this case enough tension/torque for the purpose. That may be hard to do, as Phillips-head screws do tend to cam out.* I have a diamond Phillips bit -- they are easily found -- and that makes life much easier, but it wouldn't fit in a pocket hole, as the adaptor is too wide. You might find that a bit intended for an auto-feed screwdriver system would fit, but that might wipe out any saving from not using Robertson screws (the ones branded as Kreg).

I'm sure Jacob is right about countersunk screws, but the key thing he said is "... [no worse than] in any other situation.." So let's consider that for a sec:
  • The as-drilled pocket hole has a squared-off shoulder, and the pilot hole part doesn't match the shank width of a normal screw (probably), it's narrower.
  • If it's natural material, the first part of the wood in the joint is effectively end grain. If you sink a countersunk screw in end grain, with as little material surrounding it as you get with a typical pocket hole joint, I'd expect it to split some hardwoods. Man made boards probably wouldn't be as bad.
  • Plasterboard screws are designed to hold in softwood. They have a very coarse thread, and wouldn't be suitable for some applications. Unlike the proper Robertson screws, I don't think you can get the right length in a range of threads.
  • On that topic, the pocket hole system does need fairly specific lengths of screw. My Kreg system has a table of what you should use and I find 1 1/4" is the most common size I use. If you can get that in a plasterboard head..

The obvious thing is to try it, but with the same stock at roughly the same dimensions that you intend to use. And, if it is natural wood, put the finished test joint in a warm place (in the airing cupboard or on a radiator), as shrinkage encourages splitting - you want to find the worst case, before you find it when you dont want to.

E.

PS: there are other advantages to Robertson screws, such as the fact they sit well on the driver (even a worn one), and have almost no tendency to cam out at all. I like them, and bulk prices on the internet aren't too bad really.

*You live and learn: apparently the idea that this is intentional is an urban myth. I used to believe it but, thankfully there are more knowledgeable people on the forum!
By Jacob
#1197304
Eric The Viking wrote:.......
[*]The as-drilled pocket hole has a squared-off shoulder, and the pilot hole part doesn't match the shank width of a normal screw (probably), it's narrower......!
Not as I drill! Basically drill a hole with a long twist bit for a loose fit of the screw, clean it up with a countersink and bang in a screw. No pilot hole in the far end. It's been done like that since the invention of the screw, as a cheapo quick fix and slightly stronger than nailing.
Not sure what purpose the modern gadgetry has. This maniac shows a pocket jig in use but I see no prob in doing exactly the same but without a jig, special bits/screws etc.

PS I forgot to add, I expect some will wonder; how do you drill a hole at a shallow angle with an ordinary twist bit freehand without a jig or other guide?
The answer is you start it it perpendicular to the surface until there's a little starter "pocket" (hence the name) big enough to keep the end of the bit engaged, then lift the drill to the desired angle and carry on. It will be a slightly raggedy hole so trimming with a countersink bit serves two purposes - it also allows use of any old countersunk screws
By ApplebyWT
#1199058
Kreg are the kings at the pocket hole systems. However it's not just the systems you want, the screws are the main competent for doing pocket holes. All the other brands have copied their designs and unfortunately just don't cut it. Yes they're cheaper but the quality just isn't there.
By woodywoodwood
#1204646
Hi Jacob.
I am a fan - you clearly are a talented craftsman, and I do bow down to your superior general skill. However, I have read, and then re-read your comment and would like to comment.
I think technically you may be right. A countersunk screw is, maybe, no more likely to split the wood in a countersunk or pocket hole than in normal use. However, part of the appeal of the pan-head screw in use with a pocket hole jig is that it pulls the two parts together, in some circumstances negating the need for clamps. Good practice is, of course, to clamp anyway, but the fact remains that a pan-head screw is able to successfully apply more pressure without splitting the wood. The wedge shape of countersunk screws is, of course, more likely to split than a flat bottom.
This is, I think, beyond argument. So, for me at least, in the several thousand joints I have 'jigged' with a kreg, or one of the other pocket hole systems we use, any old screw will simply NOT do.
The square drive point ( what's it called?) the kreg screws use also allow off centre driving. Again, in an ideal world unnecessary, but in my shop it lends itself to a quick turnaround.
I do agree with other aspects of your post (s) but this any old screw business is another rounded bevel! :twisted: