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.

In article ,
Richard wrote:
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.

Not so - an obvious example being car cylinder head bolts. Which screw
into the block in most cases.

--
*If horrific means to make horrible, does terrific mean to make terrible?

Dave Plowman London SW
To e-mail, change noise into sound.

On 27/09/17 06:51, Richard wrote:
On 26/09/2017 13:28, Dave Plowman (News) wrote:
In article ,
Â*Â*Â* 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.Â* 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.


No, it isn't.

A bolt is a part threaded machine screw, A machine screw is designed to
attach into a pre threaded hole, possibly in a nut. Both have constant
diameter and thread.

A Woodscrew is self cutting and so are self tappers for metal sheet and
plastic.




--
€œIt is hard to imagine a more stupid decision or more dangerous way of
making decisions than by putting those decisions in the hands of people
who pay no price for being wrong.€�

Thomas Sowell