Re: Cirular interpolation

Tony,

Does your machine directly support helical interpolation? If so,
then it's easy (see your controller manual). If not, then there are
otherways to accomplish the task.

Provided your machine will move simultaneously in X,Y,Z, thread
milling can be done by creating a toolpath made up of short straight
line (linear interpolation) segments. Years ago my only mill
wouldn't helical interpolate so I used a spreadsheet to develop the
toolpath made up of the short segments. Keep the segment length
relatively short and it's impossible to tell the difference between
this method and the helical method.

Most of the time I used a right hand lathe threading bar as my thread
mill. Start at the bottom of the hole, climb mill up out of the hole
rather than milling into the hole. Better finish with climb milling,
plus you aren't milling into a hole filled with chips. For threads
as coarse as 8tpi, you may find a roughing with a finish pass gives
best results.

Doug

--- In CAD_CAM_EDM_DRO@y..., "Tony Dickson" <antson@c...> wrote:
> Folks,
> I'm having a heck of a time trying to get my milling machine
thread a 4.500" hole with an 8 tpi thread in it. Can anyone tell me
if Bobcad, Vectorcad or Dolphin can generate code for this
particular operation. I think it might also be called helical
interpolation, I'm not sure.
> I got in on the end of the "thread milling" post a while back, I
hope I'm not repeating the same question.
>
> Thanks,
> Tony
>
>
> [Non-text portions of this message have been removed]