Confused about screws

[Adam W.]

Not as silly as it seems. If you really are unaware @civvywood , there are different drive types.
The majority in my world are PZ2 - where 2 is the size. PZ1 for small things, PZ3 for BIG things.
The wrong screwdriver can make a mess very quickly.
I think the majority in the link @Peter Sefton posted wll be PZ2. So you need a PZ2 scredriver, or PZ2 bits for your drill/driver.

Well of course I was being deadly serious, because why would you buy slotted screws when you have a pozidrive screwdriver ?

That would be silly.

 

[markblue777]

I quite like torx head screws. The bit sets in nicely and it's harder to round off the screw head.

Most of the time you will be using countersunk screws, so get a range of them. The common size I use most of 6 and 8 at various lengths.

The general rule of thumb I use is the screw goes into the connecting piece of wood by at least a 1/3, so of you have a 18mm piece of wood connecting to another piece of wood I would use a screw that goes in 6mm at least ( as long as the connecting piece has the room).

Use glue and screws where you can as the real strength will be from the glue then and you use a screw more as a clamp.

Mark

 

[Phil Pascoe]

PZ2 will cover most things, PZ1 and PH2 occasionally. If you are making trestles etc. use a larger gauge screw - not so much because the screw is stronger, but because the head is larger so you pull things up tight without burying it too deeply. Use TurboGold, Spax, Reisser or one of the better brands - cheap screws usually are junk (the basic range from Toolstation being exceptionally bad). When the head shears off or strips on a cheap one it will be in a hinge or a handle - then you'll know why you should have spent a few quid more.
https://en.wikipedia.org/wiki/List_of_screw_drives

Strangely, I watched my neighbour shear the head of a screw yesterday - in a gate hinge.

 

[Phil Pascoe]

I have found screws a good thing to make up minimum order values with for free P&P - I've got to within a few quid on a Toolstation or Screwfix order so just ordered a box of a size I'm missing or short of.

 

[pe2dave]

*Very* general advice. Stick to Pozi, get drivers for #2 or a set of 1,2 and 3.
Screws: Find a (Screwfix / any other) type of screw you like. Stick to it. Size: number 4.5 (4.5mm thread diameter) is good for most jobs.
When it gets to really beefy stuff, keep a few 5's around. Length: Enough to go through the first piece (clearance hole?) and roughly same
distance into second piece.
Suggest like chisels, you buy screws as you need them or you'll wind up with boxes that are never used. You'll soon find out
which sizes you like.
HTH

 

[JobandKnock]

When it gets to really beefy stuff, keep a few 5's around. Length: Enough to go through the first piece (clearance hole?) and roughly same
distance into second piece.

Interesting that you consider 5mm screws "beefy". On a lot of structural stuff (e.g 4 x 2 or 6 x 2 studwork, etc) we tend to use 6mm screws. They are also good for door frame/lining/casing installation, but I'd only buy them when or if you need them. They Pozi ones are invariably a PZD#3. For lighter joinery and installations 5mm screws are a good choice because they can be driven straight through a 7mm SDS bit drill hole (as required for brown plugs) but will still hold whereas the heads of 4.5mm screws are too smallto prevent pull out.

One major point about Tx drive screws (other than their higher price) - you can't cam out with them. The ability of PZD screws to cam out, or be driven slightly out of alignment, is often very handy in installation work where you may not be able to get a drill or impact driver in position in-line with the screw head and you need to cam out to be able to drive the so and so

 

[pe2dave]

Interesting that you consider 5mm screws "beefy". On a lot of structural stuff (e.g 4 x 2 or 6 x 2 studwork, etc) we tend to use 6mm screws. They are also good for door frame/lining/casing installation, but I'd only buy them when or if you need them. They Pozi ones are invariably a PZD#3. For lighter joinery and installations 5mm screws are a good choice because they can be driven straight through a 7mm SDS bit drill hole (as required for brown plugs) but will still hold whereas the heads of 4.5mm screws are too smallto prevent pull out.

One major point about Tx drive screws (other than their higher price) - you can't cam out with them. The ability of PZD screws to cam out, or be driven slightly out of alignment, is often very handy in installation work where you may not be able to get a drill or impact driver in position in-line with the screw head and you need to cam out to be able to drive the so and so

Beefy for you?
I worked on a framed building and gave up on screws, using oak pegs.
For the work I do, seldom go bigger than 4.5.
All a matter of choice?

 

[cowie122]

I would consider getting a pack like this, I am sure it will cover most of your needs.

https://www.screwfix.com/p/goldscre...cs/69034#product_additional_details_container
The most common screw size we use is 4 in various lengths as shown within the link, this is not the same as the old No 4 gauge.

I have found the grab packs to be very useful - Screwfix / B&Q

 

[Spectric]

These days only I use Reisser cutters and Timco velocity, occasionaly some Fischer powerfast. For heavy jobs then Heco Topix, you want big screws then they do 10mm by 400mm with flange or C/S head. Another screw from Heco is the Combi connect which adds structural integrity in heavy framing jobs and supports and comes in 6.5 mm upto 200 mm or 8.5 mm upto 400 mm .

 

[J-G]

Interesting that you consider 5mm screws "beefy".

...you want big screws then they do 10mm by 400mm with flange or C/S head. Another screw from Heco is the Combi connect which adds structural integrity in heavy framing jobs and supports and comes in 6.5 mm upto 200 mm or 8.5 mm upto 400 mm

I'm definitely at the other end of whatever scale you are using to describe the strength of screws! I've just ordered some 3mmØ x 8mm C/Snk because I made an error and cut a 3mm hole instead of a 2.5mm and the 2.5mm screw would have broken through the timber I'm screwing into. These screws are in the middle of my stock range - I have 'on-the-shelf' down to 1.6mmØ x 4mm in both Wood & machine screws. My biggest woodscrew is 4.5mm x 60 and machine screw M6 x 50.

This just goes to show that whatever advice anyone gives is tempered by their own usage and the best advice is as that given by AES - general pointers as to definitions, I would have added 'SupaDriv' to his list which was meant to replace PoziDriv but there wasn't a big enough difference. Trouble with Torx, Richardson Robertson and straight slot is that you must have 90° access which is not always available.

Oh yes, nearly forgot - just don't ever paint over screws! - or hinges for that matter!

 

[Spectric]

I think my style dictates bigger screws, coming from a metal background I have not mastered the woodworking finnese, so I build more traditional and solid, read overkill.

 

[AES]

Thanks for the comment J-G. I've heard of "SupaDriv" but AFAIK, they're not available here (Switzerland). How do you tell the difference (if any) between PZ and "SD" please?

 

[AES]

I think my style dictates bigger screws, coming from a metal background I have not mastered the woodworking finnese, so I build more traditional and solid, read overkill.

Yup, I'm in much the same camp Spectric!

 

[J-G]

Thanks for the comment J-G. I've heard of "SupaDriv" but AFAIK, they're not available here (Switzerland). How do you tell the difference (if any) between PZ and "SD" please?

I can't do better than point you to the wiki page - List of screw drives - Wikipedia

Some here may be surprised at how many different drive recesses there are (have been!)

The object of the change was to increase the 'out of vertical' potential which still retaining the anti-CamOut facility, officially (GKN's statement) is that Pozidriv doesn't have any out of vertical possibility but in practice we all know that there is probably a 5° tolerance - with SupaDriv you should get away with up to 15°.

 

[AES]

I can't do better than point you to the wiki page - List of screw drives - Wikipedia

Some here may be surprised at how many different drive recesses there are (have been!)

The object of the change was to increase the 'out of vertical' potential which still retaining the anti-CamOut facility, officially (GKN's statement) is that Pozidriv doesn't have any out of vertical possibility but in practice we all know that there is probably a 5° tolerance - with SupaDriv you should get away with up to 15°.

I knew they're are a lot of "oddities", but not that there are so many. Thanks.

Strange that in so many cases of mass produced "stuff" (just one e.g. - our quite high-priced/quality garden furniture) the screws used (PH 2) are totally unsuitable for the fact that it's impossible to get any driver longer than about a half inch directly over most of the installed screw heads. Grrrrhhhhhh!

But "there are ways"!!!!!!!!!!!! (Of course - designed to show just how "adaptable" us DIY-ers need to be to overcome the influence of bean counters and industrial buyers the wishes and knowledge of the designers in the company). Grrhhhhhh again.

 

[thetyreman]

(delete this)

 

[Vann]

...PZ - as above - the simple cross as above, PLUS a 2nd cross, much shallower, and set at right angles to the deep "driving cross"...

Err... maybe set at 45 degrees - not right angles.

...I certainly would not choose either Philips or pozidrive as camout is way too easy. I would standardise on torx. You will find cam out virtually a non issue...

I agree. Phillips and pozidrive are both outdated. Camout is too easy. Over here (New Zealand) square drive are overtaking ph/pz in availability and are much nicer to use. Torx are not so common, but the few I've tried have been a pleasure to use.

Once you settle on a preferred head type, buy some quality drivers and driver bits.

I also like the look of old fashion slotted brass screws - but recent efforts to replenish my stocks have run into problems - no one stocks them here anymore. I even tried the Lee Valley website (Canada) and they were out of stock of every size I looked at.

Cheers, Vann.

 

[AES]

Vann said, QUOTE: Err... maybe set at 45 degrees - not right angles. UNQUOTE:

Yup, thanks Vann, small "thought error" here!

 

[Phil Pascoe]

. Over here (New Zealand) square drive are overtaking ph/pz in availability and are much nicer to use.

My b.i.l. (34 years in NZ), a ship's joiner by trade, now a DT teacher told me 15 years ago that he very rarely saw anything except square drive used.

 

[JobandKnock]

One of the most anoying things to deal with is door ironmongery (locks, handles, keeps, closers, etc). You can pull the stuff out of the boxes to find that the lock uses PZD#2 screws, the Eurobarrels have a Tx#30 screw and the handles use Ph#2 screws. Not to bad for one door, but a PIA when you are doing multiples