[Sigia-l] Screws

[Boniface Lau]

> From: Eric Scheid
>  
> On 18/9/05 6:44 AM, "Boniface Lau" 
> <boniface_lau at compuserve.com> wrote:
> 
> > From http://www.wired.com/wired/archive/10.01/standards_pr.html:
> >
> > Wired> In cross section, virtually all screw threads were
> > Wired> triangular, but the particulars of that triangle were
> > Wired> matters of intense debate. The two sides of a Whitworth
> > Wired> thread formed an angle of 55 degrees, and its tip was
> > Wired> rounded off at the top. The Sellers thread, by contrast,
> > Wired> had a 60-degree angle, but its apex was flattened.
> 
> hmmm ... mention of cross section angles and tip treatment. No
> mention of surface characteristics.
> 
> > From http://www.forbes.com/forbes/2005/0919/066_print.html:
> > 
> > Forbes> Last year ITW introduced a plastic fastener that it calls
> > Forbes> the BosScrew. Its threads have tiny notches on their upper
> > Forbes> surfaces that grab the plastic before it can slide down
> > Forbes> the helix.
> 
> hmmm ... No mention of cross section angles and tip treatment.
> Mention of surface characteristics.
> 
> > Thus, I would not say the new screws are "still manufactured in
> > accordance with the various standards."
> 
> Try again.

Mind you, you need to actually understand what you read in order to
get the message. In this case, the message is about the shape of a
screw thread which is affected by angle, tip, surface notch, etc.


Boniface