Who decided on the sizes for Torx?

[bimmer630]

I always wondered.. Why does torx go: T10,T15,T20,T25, and then T27 (?) and then T30, Jumps to T40 (No T35) and then T45, T50, T55

Most of the T25/20 stuff could have been handled with the same size. They are so close to each other, it seems like in a lot of applications, They could have just had a T25 and not even have made the 20 a thing.
And whats the story with the redheaded stepchild, the T27? Who came up with this ****?

 

[trashmanssd]

I think the put numbers on one these and ........................

 

[Real_PhillBert]

I love Torx, and buy torx drive over philips 99% of the time; but I agree with the OP. There are too many sizes that seem redundant.

 

[drtyler]

See Post #25 for the T27 answer (also pasted below):

https://www.garagejournal.com/forum/showthread.php?p=6000736#post6000736

From member Camping57:
"I was the guy who maintained the global standards for Torx for a number of years so I pretty much know a little bit about the whole thing.
There is no such thing as a T35 Torx.
Never was, never will be.
T27 was developed because there was too big a jump between the T25 and T30 and the recesses were not big enough to drive the large screws and too big to fit into the heads of the smaller ones.
Any questions about Torx or Torx Plus I will be glad to help out on.
One key: never buy the off brand bits - the heat treat and material are really substandard- they would almost never meet the minimum torsional strength requirement in the standards. Apex, Wera, Wiha, Snap-on are all good. "

 

[gungatim]

IDK but agree it seems strange. and some sizes are near impossible to find. trying to take apart a Garmin and the torx is so small every set I look at stops at T6...yet internet search says T5...why do they skip around with occasional odd sizes???

 

[Metalio]

I have torx drivers down to T2, so they definitely exist, but you'd need to look at precision screwdrivers. For example these wera drivers go down to T1. Though I'd just buy a set with bits instead of separate drivers if you don't intend to use them often.

 

[maico]

The bases of Asus laptops are often T4, and you need that to get to the battery and memory. It's the bottom one

 

[Mr Ratchet]

I always wondered.. Why does torx go: T10,T15,T20,T25, and then T27 (?) and then T30, Jumps to T40 (No T35) and then T45, T50, T55

You missed T-47, another odd size.

 

[Michael_in_DE]

You missed T-47, another odd size.

I know that is the size for the bed bolts on my 99 f150 to hold the bed down. I am guessing its used for the seats as well.

 

[Real_PhillBert]

I know that is the size for the bed bolts on my 99 f150 to hold the bed down. I am guessing its used for the seats as well.

The seat bolts in my 02 Ford Focus were also T-47s.

 

[bimmer630]

Oh yes, T47. I forgot to include that.
That stupid size comes with all of my Torx sets.. And its got more of a round shape to the flutes.. almost like a torx plus. And since I work at BMW... I NEVER use that size

 

[maico]

I expect the odd T35 bits seen floating around come from a confused Chinese factory.
There is one here in the main photo https://www.ebay.co.uk/itm/8mm-thic...hash=item3f6a4101f1:m:mDAFcF4x0DVrGTvJ0bxHNvQ

 

[EOC_Jason]

https://en.wikipedia.org/wiki/Torx

Since none of the point-to-point distances seem to be any logical sequence I'm going to guess it is more based on the diameter of the green circle that represents the point of contact as shown in the pictures on the left side of the page linked above. Just a guess...

 

[wolf_from_wv]

I expect the odd T35 bits seen floating around come from a confused Chinese factory.
There is one here in the main photo https://www.ebay.co.uk/itm/8mm-thic...hash=item3f6a4101f1:m:mDAFcF4x0DVrGTvJ0bxHNvQ

they even made them in tamper-proof...

 

[2ndGearRubber]

Torx heads sides seem to be the smallest size possible to be able to tighten the fastener on the assembly line, not a ft/lb more. So after they've been exposed to the elements, torx is a terrible concept.


That said, having just finished some re-modeling and repairs on my new house, the t25 construction screws were great. No way I could drive a 2 inch screw through pressure treated wood with a worthless Phillips bit. Which I suppose is a god-send compared to the flat head screws on all the 60s electrical connections.


Realistically, torx, phillips, allen, they all ****. I inherently despise any fastener that requires a "male" removal tool. Triple square is mildly acceptable, but they are just so damn tight most of the time. 6 point is the correct answer for most applications. 12 is only okay when not subjected to corrosion (jeep wheel hub bolts are an example of 12point gone wrong). Inverted torx is the newest abortion to be released. Pre-rounded for your pleasure!

 

[EOC_Jason]

Why are there so many hex sizes when the simple 1/4", 3/8", or 1/2" square drive part interfacing the ratchet to the socket work so well? Conspiracy!

 

[jhn9840]

If there are T-35’s out there than why no T-37’s?

jhn9840
John

 

[wolf_from_wv]

If there are T-35’s out there than why no T-37’s?

jhn9840
John

ssshhhhhhh... They might hear you and make one...

 

[disston]

I think that T-47 was used on Fords. Stopped a Snap On truck in a self service gas station because I had a new Ford car and wanted to make sure I had the right size Torx for the rear seats. They had stopped using T-47 and now used normal hex head bolts.

Really common. The manufacturers want to use us shadetree mechanics up. Using odd sized fasteners is only one of their tricks. Now with new software we don't have much of a chance, do we?

 

[CJM8515]

After stabbing myself a few times due to the phillips bit popping out using my impact driver Im buying torx screws next time. I swear at one point gripe right made good phillips screws, but now they are dull and the heads **** the bit pops out easy.

 

[CR888]

Torx are widley used in small engine product for good reason. Outdoor power equipment like saws, brush cutters, blowers etc are now mostly held together with torx fasteners. I like them, especially with a good Wiha T-handle or 6" extended torx. With serrated fastener heads so things stay put, they are much better than Phillips or flathead type heads.