Safe Speed Forums

Completely away from driving but ...

What advantage do slotted head screws have over Pozi and Torx headed one? I haven't used a slotted screw for choice for over thirty years yet they are still around. Electricians invariably use them for fitting socket and light switch face plates, thought they rarely bother to align them neatly so appearance can't be the answer.

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When I see an adult on a bicycle, I do not despair for the future of the human race. H.G. Wells
When I see a youth in a motor car I do d.c.brown

I agree entirely, the only reason I can think why they are still produced, is because they must be cheaper to manufacture than pozis. Thay are no use to man nor beast and I always throw any away, that come with an item and substitute for pozi or philips heads. The only benefit from slotted screws, is they are easier to clean out the slot, if some idiot paints over them but the easy answer is not to paint over them.
I think some cabinet makers prefer slotted brass screws for show but when they aren't used in that case, they are totally useless.

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My views do not represent Safespeed but those of a driver who has driven for 39 yrs, in all conditions, at all times of the day & night on every type of road and covered well over a million miles, so knows a bit about what makes for safety on the road,what is really dangerous and needs to be observed when driving and quite frankly, the speedo is way down on my list of things to observe to negotiate Britain's roads safely, but I don't expect some fool who sits behind a desk all day to appreciate that.

Good question, wondered what is was going to be about mind.

I think there's another advantage though Grabs. If you have a pozi in good condition and new screws you can stick the screw on the driver and it will stay there leaving your other hand free or able to get it into tight spots.

Slotted screws are orrible but I use them occasionally because they seem to come in flat head whereas pozi always seem to be countersunk for some reason.

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

What size do you tend to use?

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My views do not represent Safespeed but those of a driver who has driven for 39 yrs, in all conditions, at all times of the day & night on every type of road and covered well over a million miles, so knows a bit about what makes for safety on the road,what is really dangerous and needs to be observed when driving and quite frankly, the speedo is way down on my list of things to observe to negotiate Britain's roads safely, but I don't expect some fool who sits behind a desk all day to appreciate that.

You caught me out there you devil; I had to go and look only to find they are Super Drive/Screw

They use the diameter of the head and the most common I use are 4mm and 5mm.

Sometimes I am screwing down on a non-countersunk hinge or something and because my OCD won't let me use a countersunk screw I have to put a cup washer under the head.

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

I'm not sure why Torx came about

I remember the first time I saw one I thought it was to thwart people from opening things because no-one had a set of drivers. But now you can buy them anywhere.

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

I always assumed they were stronger/more able to take torque.

Can't stand them.

I notice they are used on HDD's a lot. I think you've hit the Torx on the head there JtB.

A Pozi can slip out and burr over because it is a V shape but a Torx looks like it is punched down into the head squarely so it has more contact area and won't creep up and off the head.

I don't know if I said that well but I know what meant and can see it in my minds eye.

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

Both Posi and Torx were introduced to allow easier use of power tools in mass production assembly. They are both self-aligning on the driver bit and Torx has parallel sides which produces no disengagement force when driven.

The big danger with slot heads is misalignment and the tool parting company with the screw and scratching the workpiece.

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Malcolm W.
The views expressed in this post are personal opinions and do not represent the views of Safespeed.

That's what I said or meant!

Only you did say it better TBH.

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

Torx and pozi drive screws were both designed with mechanised insertion in mind - once tight, the driver slips easily away from the screw.
Robotic assembly systems can drive them in at really high speeds without damaging the screw head or driver, and Torx screws can be held on the end of the driver without any special additions such as sleeves or magnetic bits.

The advantage of slotted screws? When you don't have a driver to hand, try undoing a Pozi drive screw with a kitchen knife or a nail file, or even (on large ones) the edge of a 1p piece!

Also if you damage the end of a cross head driver, it is very difficult to repair it!

With crosshead system screws, it is important to have the appropriate screwdriver for the head.
GKNs SupaDrive was good - the driver could turn the screw even when inserted at an angle, but they were only suitable above a certain size.
Pozi Drive work down to smaller sizes than SupDrive, but the heads are easily damaged if you use the wrong size of driver for the large and small ends of the range.

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Time to take responsibility for our actions.. and don't be afraid of speaking out!

Very true. I have had my plain drivers for twenty years with the occasional regrind whereas pozis only seem to last for a couple of years.


Where do Philips head screws fit into the pantheon?

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When I see an adult on a bicycle, I do not despair for the future of the human race. H.G. Wells
When I see a youth in a motor car I do d.c.brown

Well, when I was little, ALL cross head screws were referred to as "Phillips", but I had to resort to Google to find out why!

http://en.wikipedia.org/wiki/Henry_F._Phillips
Fascinating!

I did know that Posi Drive, and GKNs Supa Drive were refinements on the Phillips screw - and the Tri Wing is used in an anti tamper application by Nintendo - because I had to resort to ebay to buy one to fix my son's Nintendo DS!!
In fact I now have a kit of bits to tackle 17 types of anti tamper screws - excluding different sizes!
Some of them are just plain bizarre. It is as if the manufacturer chose to invent a new one just for the sake of it - one is a hexagonal stepped bit which looks like several sizes of hex head (or Allen head) superimposed on each other, which engages in a similarly shaped head which must be costly to manufacture!

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Time to take responsibility for our actions.. and don't be afraid of speaking out!

What a fascinating table, or should that be fastenating , showing the 19 different head types in your link Ernest. I think some designers must have been ‘on something’ or doing it for a bet.

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The views expressed in this post are personal opinions and do not necessarily represent the views of Safe Speed.
You will be branded a threat to society by going over a speed limit where it is safe to do so, and suffer the consequences of your actions in a way criminals do not, more so than someone who is a real threat to our society.

I have actually seen some of them in use - notably the square one - which brings to mind the "square peg in a round hole" quote!

I have bits for a good number of those - including the Tri Wing I mentioned, favoured by Nintendo!

McDonalds toys are another source of strange screw heads! When you have kids you get to find out these things!!

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Time to take responsibility for our actions.. and don't be afraid of speaking out!

I hate philips/pozis with a passion, for applications with less than a tiny amount of torque they are more trouble than they are worth! Damage to heads and tools; on more than one occasion I have had to resort to chiseling them out.

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Regulation without education merely creates more criminals.

They do lend themselves to being drilled and use "Easy Outs" to unscrew them!

The drill self centres in the cross head!

I use a lot of brass screws, and the modern ones are rubbish - slotted or cross head, because the heads shear off as soon as they get tight, and have to be painstakingly drilled out.

Older screws didn't suffer this way!

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Time to take responsibility for our actions.. and don't be afraid of speaking out!

Modern screws are are threaded all the way to the head which introduces a weakness at the point of highest torque just below the head. Older screws have a long un-threaded portion which makes them great for screwing two pieces of wood together bit less than ideal for fastening thin things like hinges or metal plates. In an ideal world both types would be readily available but that would inconvenience the retailers

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When I see an adult on a bicycle, I do not despair for the future of the human race. H.G. Wells
When I see a youth in a motor car I do d.c.brown

Not in my case - I buy the ones where the thread still stops well short of the head.
The colour of the brass is a very pale yellow compared to older screws - even when freshly cut.

I am using them to fasten 1.5mm thick brass plate to benches or backing boards, and always drill the wood in steps to suit the screw... right down to a 1mm pilot to accommodate the pointed end!

I'm certain the problem arises from the choice of brass, and the method used to form the head.
To prevent it, I have resorted to screwing in a steel screw, then reversing it out and putting the brass ones in - and there are still occasions when one has sheared off!

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Time to take responsibility for our actions.. and don't be afraid of speaking out!

Ernest

Why use brass screws. Brass is a very weak material in sheer and is just not suitable for screws. It was used in the past because of its corrosion resistance but now that stainless steel is not expensive it is the material of choice.

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When I see an adult on a bicycle, I do not despair for the future of the human race. H.G. Wells
When I see a youth in a motor car I do d.c.brown