[Sigia-l] Screws

[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 triangular,
> Wired> but the particulars of that triangle were matters of intense
> Wired> debate. The two sides of a Whitworth thread formed an angle of
> Wired> 55 degrees, and its tip was rounded off at the top. The Sellers
> Wired> thread, by contrast, had a 60-degree angle, but its apex was
> Wired> 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 the
> Forbes> BosScrew. Its threads have tiny notches on their upper
> Forbes> surfaces that grab the plastic before it can slide down the
> Forbes> 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.

e.