does anyone know why certain phillips head wood screws dont pull in tight? I've done a few DIY jobs in recent times, usually these type of screws pull the wood surfaces together really tight but I've used screws from BQ and Screwfix and you actually have to almost cramp the two wood faces together to get them screwed tight and thats with a pilot hole as well!
screws that dont pull up tight
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kostello
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If they are threaded along the whole shank it is difficult to get them to pull tight without backing the screw out and then retightening it
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A screw threaded to the head is really unlikely to pull two pieces together - in effect, the screw is just like a piece of threaded rod going through two nuts. Unless you can rotate one piece along the thread, they will both stay in whatever position they were in when the screw established a thread in them.
Best practice with the old-style woodscrews was, if possible, to choose a size such that the piece to be pulled close was the same thickness as the plain shank if the screw.
Best practice with the old-style woodscrews was, if possible, to choose a size such that the piece to be pulled close was the same thickness as the plain shank if the screw.
Eric The Viking
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Two things:
Some woodscrews are double-start. That means two threads intertwined, so you get twice the in-out distance per rotation. These aren't good for tightness, although they are quick to use.
Secondly, what others have said - drive the screw right through the first piece, so it penetrates the piece below, then back it out, apply pressure and then fully tighten it.
Finally, if they're not plasterboard screws, they're most probably Pozidriv, not Phillips. The Phillips ones have a thinner "X", and the Pozi ones usually have a second "X" set of lines on the diagonal too (not actual slots). It's wise not to try to drive either with the wrong driver.
Personally, I greatly prefer the diamond bits (with industrial diamond chips embedded in the metal), as they grip far better than any other bits I've come across.
Some woodscrews are double-start. That means two threads intertwined, so you get twice the in-out distance per rotation. These aren't good for tightness, although they are quick to use.
Secondly, what others have said - drive the screw right through the first piece, so it penetrates the piece below, then back it out, apply pressure and then fully tighten it.
Finally, if they're not plasterboard screws, they're most probably Pozidriv, not Phillips. The Phillips ones have a thinner "X", and the Pozi ones usually have a second "X" set of lines on the diagonal too (not actual slots). It's wise not to try to drive either with the wrong driver.
Personally, I greatly prefer the diamond bits (with industrial diamond chips embedded in the metal), as they grip far better than any other bits I've come across.
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Use a clearence hole in the countersunk piece of timber and it should pull up fine.
Cheers Peter
Cheers Peter
Random Orbital Bob
Established Member
+1 for a pilot clearance hole. I'm always amazed at how many people don't actually know how to screw two pieces of wood tight together! get your drill bits and make a template of one hole per bit in a row. When you come to choose your screw, place it in each hole until you get a fit where it doesn't bite but isn't floppy either. That's the correct drill bit to use for the clearance hole. Drill it, countersink it and then screw and its the HEAD of the screw that pulls the boards in tight not the threads. The purpose of the threads is to lock in the underside piece. This is how it was always done until these new fangled spax/reisser etc etc came out claiming to screw anything to anything without pilot holes or countersinking. For framing a roof or stud wall or where it wont show in chunky bits of 4x2 then fair enough, especially with an impact driver. But for furniture, or close to the edge of a board....rubbish. There's no substitute for a proper clearance hole and careful countersinking with a seriously sharp countersink.
blackrodd
Established Member
As members have said, the screw, exiting the first piece, momentarily spins before entering the second piece
and so allows a small gap.
Either back the screw out and drive it back in, drill a pilot hole or clamp the two pieces together tight in the fixing area, with a quick clamp before screwing.
Regards Rodders
and so allows a small gap.
Either back the screw out and drive it back in, drill a pilot hole or clamp the two pieces together tight in the fixing area, with a quick clamp before screwing.
Regards Rodders
lol a screw tutorial thread 
I forgot to add that none of this is to do with furniture (which is precision and needs doing properly) just stuff like stud partitions. Last job I did was put up a 3x2 softwood framework for a lean to and the screws were a right pain - nothing like I'd remembered in the past when doing roughish work like this when the screws used to fly in with no pilot and grab the wood together really tight instantly so I just got to thinking where am i going wrong all of a sudden!
I forgot to add that none of this is to do with furniture (which is precision and needs doing properly) just stuff like stud partitions. Last job I did was put up a 3x2 softwood framework for a lean to and the screws were a right pain - nothing like I'd remembered in the past when doing roughish work like this when the screws used to fly in with no pilot and grab the wood together really tight instantly so I just got to thinking where am i going wrong all of a sudden!blackrodd
Established Member
Matt@":1rrpkjx2 said:lol a screw tutorial thread
The better screws, spax, f'rinstance seem to be easiest to use, I've just used up my stocks of 70mmx3mm,
They're easy and quick start for screwing on the skew in studwork, that don't split and look a real dog
Jewson, etc are ok budget screws but not always easy to find other than 60mmx4mm lately.
Regards Rodders
The last ones I bought were a big tub of approx 3" x 10 from BQ and it is these that have been giving the hassle. Now I come to think of it, they are threaded to the head and have a very fancy thread - they are useless though as will not draw faces together dead tight even after reversing and going in again and from memory I did pilot them. Previous poster is right I think, many dont know how to use a screw even some who should know better
Phil Pascoe
Established Member
Also it pays to slightly countersink or at least sand the exit of your clearance hole - when the bit bursts through, it often creates a slight bulge or splinter which will prevent the pieces pulling together.
No skills
Established Member
All of the above +1 or just borrow a nail gun for your studwork.
rafezetter
Troll Hunter
+1 to all of the above - especially the blowout of wood between 1st and 2nd section Phil.P mentions; especially covered chipboard / OSB, they are both terrible for it. If I've been lazy (or forgotten to bring clearance hole & pilot hole drillbits) I'll screw and back out maybe 3-4 times in stages to make sure it brings it up tight.
And it's no bad thing to mention how to apply screws correctly, as mentioned there's many a person who just thinks "bang a screw in" and it's sorted. On friday I had to remove an Oak tabletop from a table we had delivered just the day before as it needed some slight (understatement alert, it took me hours....) attention that had been fixed with buttons as it should. But the person who screwed the buttons on, not me I hasten to add, had used pozi headed screws too short, no pilot hole and applied them with an impact drill by a person with almost zero experience of using one.
Needless to say the heads were totally stripped, requiring me to incrementally drill off the heads to remove the buttons then tease out the screws with molegrips, and plug the now damaged screw holes, before I could even set to work on the problems of wobbly legs. (again not my fault, item was delivered without my checking the table for problems).
And it's no bad thing to mention how to apply screws correctly, as mentioned there's many a person who just thinks "bang a screw in" and it's sorted. On friday I had to remove an Oak tabletop from a table we had delivered just the day before as it needed some slight (understatement alert, it took me hours....) attention that had been fixed with buttons as it should. But the person who screwed the buttons on, not me I hasten to add, had used pozi headed screws too short, no pilot hole and applied them with an impact drill by a person with almost zero experience of using one.
Needless to say the heads were totally stripped, requiring me to incrementally drill off the heads to remove the buttons then tease out the screws with molegrips, and plug the now damaged screw holes, before I could even set to work on the problems of wobbly legs. (again not my fault, item was delivered without my checking the table for problems).
Random Orbital Bob
Established Member
rafezetter":2nak5q3o said:
That kind of workmanship, or lack of it would drive me insane! I have to say that the new crop of impact drivers are amazingly useful in the right hands but in the wrong hands and for the wrong job....Why do people want to use the National grid or battery equivalent for every job? Whatever happened to "feeling" when the screw has gone home and just snug it up, especially in quality furniture? It sometimes seems to me that there's a new breed that think every piece of wood is a fencing job regardless the project!
By the way, OP...you can buy drill bits that have either a counter bore or countersink (or both) attached to the drill so you don't need two operations like in the old days. As someone else said, to avoid blowout at the sandwich between the boards, mildly countersink the exit hole (which will be invisible anyway). I have to be honest, for fine furniture work I still use my yankee drivers, different sizes for different jobs because then I'm in touch with the torque of the screw and I know when it feels just right. Any form of powered driver technology cuts you off from that feeling though for speed the torque clutches can help of course.
Phil Pascoe
Established Member
Our club uses an impact driver - on screws that will be reused dozens of times. Bought for the purpose - how daft is that? They wonder why the screws are always fubar.
Eric The Viking
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Random Orbital Bob":1gxy8m9w said:
That simply isn't true. It's just a different technique. As someone who owns a Yankee, I know they're not *****-proof either - you have to feel your way with both, but both work well.
Many years ago, I had to stop using manual screwdrivers (for most things), after stupidly starting to repair a boarded floor by hand, using 'twinquick' screws. Tennis elbow was the result, and it was really painful. A year or two later arthritis sealed the deal, and now manual screwdrivers are for special circumstances only, most often when re-assembling plastic home electronics (where you really need precise feel or it's game over). Even there, I dismantle using an electric driver, as it's faster and better for both screws and plastics.
One has to learn to use electric properly, and adjustable clutches are good, but you don't really need them (my first cordless drill didn't have any sort of clutch) you do need reliable varispeed though.
Although I have one and like it a lot, electric 'rattle guns' (impact drivers) only have very limited use in woody applications, made worse by modern screws (self countersinking screws and rattle guns do NOT go well together!).
The big difficulty is that you need to feel the point where the screw finally pulls up into the stock. A rattle gun drives too well, especially with any type of good driving bit fitted. Unless you use a lot of care in softwood, it's one or two thumps of the gun between a screw not driven home and one that's punched below the surface nastily. I think that's in no small part down to screw design, and having no subtlety in the 'thumper' mechanics of the driver.
As for mangled screw heads afterwards, obviously it's poor technique. In my experience, a screw properly driven by an impact driver usually has less damage than one from a non-impact electric tool, assuming the use of a good quality engagement system (the screw head and bit type). If the head is already damaged though, an impact driver can make matters a lot worse very fast.
That said, for me an electric driver will remove screws that can't be shifted any other way. I think that's because I can concentrate on keeping it straight and the amount of force I'm applying. I rarely attempt to shift anything stubborn with an impact driver, as I've had too many failures in the past. The old 'thump the back' manual ones are OK, but not the electric ones.
E.
Phil Pascoe
Established Member
I suspect the damage is done in a woodturning environment because using a faceplate or a faceplate ring, the screw goes from moving to absolutely dead in a part turn - there is no "give", coupled with most screwdriver bits in that environment being garbage, also.
Jacob
What goes around comes around.
I use yankees a lot too. One of the less obvious advantages is the length - it makes it easier to get a square on good fit.
As has been said - the OPs prob is solved by drilling a pilot hole through the first layer - so that the screw is a loose fit. Same if it's an old screw with a plain shank. No risk of blow out either. There's no particular point in having the screw threads engaged in the top layer, or a plain shank as a tight fit - it's held by the head.
PS adjustable torque clutches are brilliant on a power drill; they work a bit like an impact driver if removing a screw, and avoid the risk of cam out if you are tightening one.
As has been said - the OPs prob is solved by drilling a pilot hole through the first layer - so that the screw is a loose fit. Same if it's an old screw with a plain shank. No risk of blow out either. There's no particular point in having the screw threads engaged in the top layer, or a plain shank as a tight fit - it's held by the head.
PS adjustable torque clutches are brilliant on a power drill; they work a bit like an impact driver if removing a screw, and avoid the risk of cam out if you are tightening one.
worn thumbs
Established Member
Peter Sefton":2t2poeyt said:
Some of the most necessary advice ever for screws.Also some of the most likely to be ignored.
