screw head type

[333rocky333]

Had to remove some ductwork recently to get at the fan.
The duct was held together with self tapping type screws, but the heads at first glance looked like allen keys, but were actually square holes, aprox 2.5 mm square.
looked at all these multi kits which appear to have every type adapter you could need.
But unable to find something to fit..
Any advise welcome

 

[JohnW2]

.... the heads at first glance looked like allen keys, but were actually square holes, aprox 2.5 mm square. ... looked at all these multi kits which appear to have every type adapter you could need. But unable to find something to fit..

I agree that the multi-kits rarely have them but, in my experience, the square hole ones are usually quite easy to deal with - it's usually the case that I can find a hex or star bit (from a 'multi-kit') that will fit and grip sufficiently well - or, if one is lucky, a small straight bit that fits nicely (diagonally) across the square.

Kind Regards, John

 

[EFLImpudence]

They're called square drive.

Can't find any here.
http://www-de.wera.de/catalog_de.ht..._wera_bits_bits_for_square_socket_screws.html

 

[EFLImpudence]

http://www.ebay.co.uk/sch/i.html?_f...ive+bits.TRS0&_nkw=square+drive+bits&_sacat=0

 

[333rocky333]

They're called square drive.

Never thought of that.

They look the type but hard to tell the width, I take it theres various sizes, think I will pass as hopefully wont need one again.

 

[Risteard]

They're called square drive.

Or Scrulox. Everyone here uses them for all electrical installation work.

 

[333rocky333]

...

 

[rsgaz]

square holes, aprox 2.5 mm

That will be a "number 1 square drive" then, actually 3/32 inch (so 2.38mm). The 'number 2' is 1/8 inch; 3.175mm.

Canadians call them Robertson drive, but Robertson drive tips are tapered in order to grab the screw so it won't fall off the end of the driver during use.

Gaz

 

[rsgaz]

think I will pass

A set like this will cover everything you'll ever want...

http://www.ebay.co.uk/itm/191960385353
http://www.ebay.co.uk/itm/191960385353
...but being just a cheapo set, don't ever put them in a drill, just use a hand driver, or they'll be ruined in no time.

Gaz

 

[Lectrician]

They seem to be regularly used in commercial kitchen canopies and extraction. I acquired a bit from the fabricator

 

[333rocky333]

They seem to be regularly used in commercial kitchen canopies and extraction. I acquired a bit from the fabricator

Yes, this was a tesco bakery, I had never seen them before, it was a pain using an old flat head screwdriver and then a pair of grips on the tighter ones.
Thinking about it, i could have filed a torx bit square to fit

 

[333rocky333]

A set like this will cover everything you'll ever want...

http://www.ebay.co.uk/itm/191960385353
...but being just a cheapo set, don't ever put them in a drill, just use a hand driver, or they'll be ruined in no time.

Gaz

Just realised I have that set in the garage, forgot I had it.
All my other sets on the van dont have them in

 

[333rocky333]

I agree that the multi-kits rarely have them but, in my experience, the square hole ones are usually quite easy to deal with - it's usually the case that I can find a hex or star bit (from a 'multi-kit') that will fit and grip sufficiently well - or, if one is lucky, a small straight bit that fits nicely (diagonally) across the square.

Kind Regards, John

Only just noticed this reply
Thats what we did in the end, but some were so tight, had to get grips on the side of the screwhead

 

[Lectrician]

The steel fabricators that install canopies and ducting/extraction usually use these for some reason. I guess they all use the same suppliers I've come across them quite often on installs, so assume they are common place in that trade.

 

[Iggifer]

Only just noticed this reply
Thats what we did in the end, but some were so tight, had to get grips on the side of the screwhead

Also happens when they round off (some seem to be made of butter) I've also found a pair of end nipping pliers work well, make more of a mess of the screw than grips might but once you've applied force, its coming out no messing.