On 26/09/2017 13:28, Dave Plowman (News) wrote:
In article ,
Graeme wrote:
In message , Huge
writes
On 2017-09-26, Graeme wrote:

Why is a machine screw called a screw when it is a bolt?

Because it isn't a bolt.

OK. I have always assumed that anything with a parallel shaft or thread
is a bolt, but anything with a tapered shaft and thread is a screw, but
apparently not.

Huge's definition is certainly the one I remember - a bolt isn't threaded
all the way. But just when a machine screw becomes just a screw I dunno.

A bolt is a screw if screwed into something rather than having a nut
attached.


Bolt probably comes from the same root as a bolt for the door. It locates
the two parts due to being a good fit before being tightened.