Countersink on External Torx Plus Sockets

[The Critic]

It was recently brought to my attention that most of Snap-On’s External Torx Plus sockets contain a countersink. Snap-On says the countersink is required for proper engagement of “low-profile” External Torx Plus fasteners. I have attached a copy of the Snap-On literature that illustrates this.


No other brands have identified the countersink feature in their External Torx Plus sockets. In the below picture, the VIM EP24 socket has the countersink but the OTC one did not.

I have not encountered any low profile External Torx Plus fasteners myself, but if you have, you may want to check if your sockets have the countersink.

 

[L.Cheapo]

I don't know why manufacturers have to make things so complicated. Torx, Etorx, Torx Plus, Etorx Plus, and now Low Profile Etorx Plus?

 

[Chipm]

Low profile looks like maybe the bolts on the undertray of a Corvette, but torx plus works fine for me. No idea if they have a countersink or not.

From your photo, I can't see much of a difference. What exactly am I looking at?

 

[Chipm]

OH! i get it now - the fancy FLEPL ones have a REDUCED countersink compared to FLEP, as in the engagement teeth are closer to the end of the socket. The LP fasteners are not tall enough to reach the teeth on a normal-countersink socket.

You want less countersink for low profile fasteners, not more. The OTC socket would work better on low profile than VIM.

 

[The Critic]

You want less countersink for low profile fasteners, not more. The OTC socket would work better on low profile than VIM.

Edit: I think you are correct.

 

[KnurledNut]

I don't know why manufacturers have to make things so complicated. Torx, Etorx, Torx Plus, Etorx Plus, and now Low Profile Etorx Plus?

If it makes ya feel any better they make ULTRA low profile E-Torx Plus fasteners too.

 

[darkzero]

I've encountered them. Had to machine down my socket to fit, just a HF Pittsburgh so I didn't hesitate to.



Also later machined down my coworker's Bluepoint socket.

 

[2ndGearRubber]

I've encountered them. Had to machine down my socket to fit, just a HF Pittsburgh so I didn't hesitate to.



Also later machined down my coworker's Bluepoint socket.

I've done that for partially rounded Etorx, using a roloc, flap wheel, or cut off disc. Yours look much prettier.

The low profile style basically just remove lead-in taper which external torx always had in obnoxious amounts. Ford? or somebody is using them for fender bolts in the engine bay.

 

[KnurledNut]

I've encountered them. Had to machine down my socket to fit, just a HF Pittsburgh so I didn't hesitate to.



Also later machined down my coworker's Bluepoint socket.

Those sockets appear to be standard torx, not plus, no?

 

[KnurledNut]

The low profile style basically just remove lead-in taper which external torx always had in obnoxious amounts. Ford? or somebody is using them for fender bolts in the engine bay.

It's not for lead-in. Its for full engagement on the splines below the dome.

 

[2ndGearRubber]

It's not for lead-in. Its for full engagement on the splines below the dome.

Perhaps lead-in was a poor choice of words, it's not lead-in in the way a 6pt socket has the taper at the entry interface. I was commenting on the design of the drive tool/fastener itself.

 

[KnurledNut]

Perhaps lead-in was a poor choice of words, it's not lead-in in the way a 6pt socket has the taper at the entry interface. I was commenting on the design of the drive tool/fastener itself.

Drive tool to fastener interface is really all that matters. That's where problems begin when the proper tool isn't available and demands have to be met. There is also the ignorance factor of many that are unaware of all these drive interfaces. And one can't discount a crusty fastener in a tight spot that's all but impossible to see, leaving the worker to guess at what they are dealing with. The old "close enough" socket wiggle test comes into play.

For those new to these designs and trying to learn:
A countersunk socket is a poor choice for a standard non-low profile head because critical engagement is lost, especially on high torque applications.
The name itself can be confusing, because one naturally would think this is talking about the deep countersink on standard EP rather than the shallow countersink on tooling designated as such.
To make things more confusing, some regular EP sockets have a shallow countersink but are not designated as such, again leading to poor engagement by those unaware of the options.

On the other hand, a standard deep chamfer socket is a going to cause limited contact on low profile fasteners and could slip.
E-torx geometry is interesting to me because you have to think about it backwards.

In a nutshell, I feel like it would be beneficial if a tool manufacturer offered a master set of external torx sockets that came with three profiles, standard deep chamfer, shallow countersink, and the one that doesn't exist but seems necessary for ultra low profile, a completely flat end.

 

[Professor Gascan]

How common are these external torx plus fasteners becoming? I've only run across regular e torx bolts on a relatives Chevy Aveo that had quite a few under the hood.

 

[darkzero]

I've done that for partially rounded Etorx, using a roloc, flap wheel, or cut off disc. Yours look much prettier.

The low profile style basically just remove lead-in taper which external torx always had in obnoxious amounts. Ford? or somebody is using them for fender bolts in the engine bay.

Yep, in our case they are on a Ford. The only one specific vehicle & bolt size we run into.

Those sockets appear to be standard torx, not plus, no?

Yes

 

[KnurledNut]

How common are these external torx plus fasteners becoming? I've only run across regular e torx bolts on a relatives Chevy Aveo that had quite a few under the hood.

Rare.
A well known example is the low profile Ford bed bolts.

 

[2ndGearRubber]

Rare.
A well known example is the low profile Ford bed bolts.

Depends on what you work on. GM 1.4L and 1.8L in the cruze/trax are covered in them, as are Benz. It's a euro thing, but it's a global world, so they pop up where you wouldn't initially expect.

 

[Chipm]

How common are these external torx plus fasteners becoming?

Engine/trans undertray on C8 Corvette has low-profile torx plus.