Why is this socket so shallow?

[jacked_72]

This is an older S-K socket. I'm wondering why effective portion of the socket is so shallow. Seems like a good way to round off some bolts.

 

[Moose-LandTran]

It appears to be a special purpose one, probably for something like an oil pressure sensor. They only have a shallow hex, but the socket needs a large inner bore like that to clear the sensor body.

 

[redwrench60]

This is called broach depth. It's on purpose so a nut or bolt wont disappear down in the socket. It's an advantage when using a long extension and feeding a fastener into a tight area to start it in a bolt hole.

 

[redwrench60]

It appears to be a special purpose one, probably for something like an oil pressure sensor. They only have a shallow hex, but the socket needs a large inner bore like that to clear the sensor body.

I just saw it does have knurling at the base, is that a spark plug socket?

 

[jacked_72]

I guess it is a spark plug socket I see the remains of old rubber on the inside I hadn't noticed before. It is 13/16". Mystery solved. Thanks.