Re: [CAD_CAM_EDM_DRO] Helix Angle

The helix angle can be generated by 'unrolling' the thread: The
circumference of the thread is 'pi' times diameter, so C = .7087" times
3.14159.. 2.2264467".., and the pitch is .125 ". The angle generated then,
has a tangent of (0.125 divided by 2.2264467 = 0.0561433), therefore the
angle is 3.2134°. Where in the world do you have an application that
utilizes 18mm dia, and 8 tpi??? Don't forget that if you're generating a
60° form thread, that you don't tilt the cutter by the helix angle... the
60° form is measured parallel to the axis. i.e., you don't have to
foreshorten the shape of the angle. But, you do have to make sure the
relief angles of the cutters are greater than 3.2134°.

RayHex

----------

> From: Terry Owens <terry@...>
>
> 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
>
>
>
>
> Addresses:
> FAQ: http://www.ktmarketing.com/faq.html
> FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
> Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com
>
> Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
> Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
> List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@...,

timg@...

> Moderator: pentam@... indigo_red@... davemucha@...

[Moderators]

> URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
>
> OFF Topic POSTS: General Machining
> If you wish to post on unlimited OT subjects goto:

aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if
you have trouble.

> http://www.metalworking.com/news_servers.html
>
> http://groups.yahoo.com/group/jobshophomeshop I consider this to be a

sister site to the CCED group, as many of the same members are there, for
OT subjects, that are not allowed on the CCED list.

>
> NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM.

DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........

> bill
> List Mom
> List Owner
>
>
> Yahoo! Groups Links
>
>
>
>