Re: Helix Angle

What I did was draw the diameter (.7087) as the base of a right
triangle. I then drew the pitch of the thread (1/8 or .125) as the
vertical side of the triangle. Using SO CA TOA I calculated the
inverse of the tangent (Tan = Opposite over Adjacent) on my
calculator and came up with 10.003 degrees. Like I said if that's
wrong someone (or lots of people) will shortly correct this.
Ralph Wenzl


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Terry Owens" <terry@o...>
wrote:

> Hi,
>
> This may at first sight appaer to be off-topic but it isn't. I nned

to know

> the answer so I can draw it in CAD to make a part for a CNC machine.
>
> If I had a piece of round bar 18mm (0.7087") and cut an 8TPI thread

in it

> how would I work out the helix angle of the thread?
>
> Regards,
>
> Terry