Subject: Re: A *really* weird thread

From: [email-masked] (Andrew Vida-Szucs)
Date: Fri, 8 Apr 1994 13:23:29 GMT

[email-masked] writes:

	[schnip]

|> What is *really* bizzare is that the thread angle is *NOT*
|> 60 degrees, but closer to 55 degrees!   I have searched
|> Machinery's Handbook and Guide To World Screw Threads, but
|> can find nothing that matches this.   All the other fasteners 
|> on this dividing head are common American threads (1/2"-20, 
|> #10-24, etc.).    The internal taper in the spindle nose
|> appears to be a Brown & Sharp #7, but I don't have one
|> to check it against.

	55 degrees you say?  Could be a Whitworth thread.  If the
	crests and troughs of the thread are radiused, rather than
	pointed or flat, then I'd bet this is what it is.  This
	was, at least at one time, the standard thread in Brittain.

	I may have the 55 degree angle confused with another thread.
	At any rate I know there is a 55 degree thread out there,
	either the Whitworth or something else.  I'll look it up 
	and post if I have been mistaken here.

	-Andy V.