posi woodscrews v Torx

[powertools]

After a life time in the motor trade I hate torx with a passion pozi for me.

 

[AES]

@marcros: I don't KNOW this but assume that pianos are always (or almost always) made of hardwood? And I also assume that as the screws for the hinges will almost certainly be brass, so I guess that a pilot is always used - probably even a 2 stage pilot. In which case I GUESS there's little chance of under or over-torqueing - rpt, just my GUESS.

For clocks, though I've not done it myself (yet - that's still to come - one of these fine wet days!) I've read that the "trick" if a visible screw/bolt head won't come exactly into line is to remove the screw and give the hole just a very gentle extra touch with a sharp c/s bit. Again brass screws/bolts into brass frames/plates, so I agree, one would have to be a bit gentle. Again my guess is that as experience grows (and as you've had to remove a couple of sheared bolts!) you gain a feel for how tight to go.

@voyager: Agreed, you do have to be a bit careful with SS. Generally they seem to be a bit "weaker" in tension than steel. Again, "feel" is the answer I think - if tightening suddenly becomes too easy then it's already too late! (DAMHIKT).

 

[wsb1207]

Very high end pianos fit their piano hinges with brass slotted screws and go to great lengths to align all the slots. I notice this kind of thing

So do I, as an apprentice we were taught to 'dress' the heads of slotted screws. I have to admit, it irritates me far more than it should if I see some that aren't lined up! :x

 

[Freddyjersey2016]

I have had a few stainless ones snap,
however this is a combination of stainless being a fairly brittle material and the impact driver now being in common usage, back when it was a stanley screwdriver (lost so much finger skin to those things over the years) then everyone got cordless drills and the level of head stripping went up, now the once rare impact screwdriver is in common usage , cheap screws just dont stand a chance.

I suspect that as stainless steel is more expensive that the manufacturers make the shanks of s/s screws thinner than the equivalent zinc plated ones - that certainly seems to be my experience that they snap more easily. (though i also remember it was fairly easy to snap slotted head no 12 screws if you put them in with a screwdriver bit in a brace, but I was younger and less experienced then)

 

[Jake]

The small difference between Torx sizes at the smaller end is a bit of a negative trial-and-error fiddle. They also just aren't as quick IMO when driving lots and lots of repetitive screws, just because Pozi has a bigger acceptance angle (the cost being more risk of cam out once you are in as it were). I haven't noticed wearing out more on Torx, Pozi seem worse and to shatter more often under duress.

Been using a metric sht-ton of big/long fasteners doing my attic. TX50 is a brute and really hard to source bits for but at that size most turn to internal hex or external hex with an internal hex. Not had any difficulties with any of those. Torx is slightly easier due to the taper.

 

[AESamuel]

Can't stand pozi, the amount of inline force needed to get enough torque without the head slipping out is ridiculous!

Torx is great and my current choice! Unless it's something which needs to look halfway decent, in which case I go for slotted. Don't know why but they are the most aesthetically pleasing IMO.

 

[thetyreman]

never had a real problem with pozi head screws, I've yet to try torx though, what I have noticed though is pozi screwsvary in quality, well worth getting better quality screws and paying a bit more, the grip will be more pozitive.....

 

[Jake]

never had a real problem with pozi head screws, I've yet to try torx though, what I have noticed though is pozi screwsvary in quality, well worth getting better quality screws and paying a bit more, the grip will be more pozitive.....

Life's too short to put with bad screws.

 

[Andy Kev.]

Very high end pianos fit their piano hinges with brass slotted screws and go to great lengths to align all the slots. I notice this kind of thing

And if they were anything other than slotted, would they look as special? Or just ordinary?

I wonder if it's one of those things that only matters to people over about 50?

I think that if a screw is to be visible and appearance matters then it needs to be slotted. If the only factor is mechanical then it is just a matter of using the head you find best for your purposes.

 

[AJB Temple]

Re Piano screws and torquing / lining up, I had this conversation with Richard Dain (an engineer who worked with Frank Whittle) who designed Phoenix Pianos. He says it leads to over tightening. He actually uses stainless steel slotted screws in brass hinges in piano lids.

I went round the Bechstein factory a few years ago. The lid screw holes are done on a jig with a special bit that matches the thread and taper. The screw slots are aligned by hand. If you go to the Bechstein showroom in Koln / Cologne, you can see their tier 1 pianos have perfectly aligned screws, whereas their lower tier stuff (can't remember the branding they use) do not.

High end pianos are likely have hardwood lids, but many cheaper brands (usually Chinese now) have veneered MDF lids and some have hollow core lids. Weight is a factor on big pianos. Mine is a Steingraeber Phoenix and the lid is hardwood and the underside veneered with figured maple. I had to line up the screws myself. Couldn't stand looking at them all misaligned!

 

[AES]

That's very interesting and informative "AJBT", thanks.

 

[TheTiddles]

Very high end pianos fit their piano hinges with brass slotted screws and go to great lengths to align all the slots. I notice this kind of thing

Isn't the counter argument that in doing so, some must be under or over torqued to ensure that they align?

There is a way of aligning heads and not having this (so long as the thread start is consistent with the slot orientation on all screws, you can specify this on high-end screws) by placing a ruler or similar in all the slots then pressing them down into the pilots... this works fine on two or three, how you'd domitmon a piano I suspect would be a right faff

Aidan

 

[mbartlett99]

The superyacht interior guys went to torx ages go and I love it - so much easier in a tight space. Gotta use the right gear though - Spax screws + decent driver . If its visible I'll still use slotted all heads clocked.

 

[Phil Pascoe]

My bil, who was a ship's joiner in NZ told me years ago that no one there uses anything other than square drive.

 

[worn thumbs]

I haven't got an impact driver and don't intend to buy one for screwdriving.My feeling is that its a bit like the tyre fitters who use impact drivers,rather than correctly torquing the wheel nuts.You get the fastener done up quickly but out side the slap it together and move on fast type of work,why would you.The price work mob may get away with it but I'm glad to have no part of that sort of stuff even if it may have cost me.I prefer to operate with proper screws-those that have plain shanks-and if it takes a little more time to drill a clearance hole and a pilot hole,so be it.I have put in over 4000 slot head screws with a Stanley pump screwdriver in a single day a tool I haven't picked up in about twenty five years.From the point of view of driving efficiency a Torx has to be about the best compromise because of the number of slots and their depth.Philips or similar probably about the worst and I was staggered to see how many variations on cross head exist.I get exasperated when DIY'ers ask for Philips screws or screwdrivers when they ought to be describing pozidriv.I know the square recess has a very keen following but the geometry seems all wrong and they are a pig to deal with if the heads are full of paint.For repair work you have to enjoy the simplicity of cleaning a plain slot compared to any of the others.

 

[TheTiddles]

I don’t think there will ever be a standard, this isn’t the Soviet Union, no comrade will decide for all of us.

They all have their advantages and disadvantages, the thing that makes me cringe is the number of people who don’t understand them, which is amusing till it’s their job to know and they still don’t. It’s like listening to someone complaining their vice handle bent, or their gazpacho has gone cold.

Aidan

 

[mbartlett99]

My bil, who was a ship's joiner in NZ told me years ago that no one there uses anything other than square drive.

Yup. Kiwi and Aussy yards are very keen on the Robinsons and its not a terrible solution at all. North European went torx ages ago.

 

[thetyreman]

never had a real problem with pozi head screws, I've yet to try torx though, what I have noticed though is pozi screwsvary in quality, well worth getting better quality screws and paying a bit more, the grip will be more pozitive.....

Life's too short to put with bad screws.

exactly, every screw should be savoured :lol:

 

[Silly_Billy]

their gazpacho has gone cold.

I hate it when that happens :lol:

 

[voyager]

here's a quick guide to screw head variations, i must admit a few were new to me,

https://www.wiha.com/gb/en/service/screw-profile-guide/