I have cut threads that way.
the tooling
http://www.collection.archivist.info/archive/DJCPD/PD/2009/2009_08_13_cnc/P1010245.JPG

I also tilt the rotary axis so the cut properly follows the helix,
this requires some maths in the gcode to follow the tilted path

before I made that tool and also before the B axis I made a worm
jacking the rotary to the required angle with some packing
http://www.youtube.com/watch?v=Jbp8SJ9RxqI

Dave Caroline

On Mon, Dec 26, 2011 at 8:00 AM, gene heskett <ghesk...@wdtv.com> wrote:
> Greetings;
>
> I've about worn out that 7x10 I have, and its rubber tool post prevents me
> from doing anything resembling a fine finish regardless of the sharpness of
> the bit.  When cutting threads I have to, before reversing the spindle to
> back away & reset to deepen the cut on the next pass, back the crossfeed
> off a full turn to keep the bit from dragging on the thread as it
> supposedly retraces its path backwards.  I knew it was a toy when I bought
> it, and I'm considering its replacement with something big enough that its
> worthwhile cnc'ing it.
>
> I have a need for cutting a clean, nearly interference fitted 1/4x28
> external thread for a distance of about 1/4", immediately adjacent to a
> 1/2" diameter seating plane when this is screwed into its receiver.
>
> I don't have an encoder on either the lathe or the mills spindle, so the
> thought runs toward a flying cutter in the mill spindle whose tip profile
> is that of the 60 degree included angle tooth.
>
> Now, the cutter would be working on the side of the workpiece, mounted with
> the axis vertical in a chuck on a rotary table, turning very slowly as the
> z axis travels in 1/28 step.
>
> Since I can run the z axis and a axis in lock step, what prevents me from
> cutting this thread with the fly cutter other than finding a suitable fly
> cutter?
>
> I thought so, so where in tunket can I find such a fly cutter that is
> actually holding a single point threading insert, perhaps an inch in
> diameter overall.  Googling hasn't found such a beast at less than 3" in
> diameter and many BIG bucks cost.  Or is this just another tool I'll have
> to make, in which case it will be holding a less easily fractured square
> piece of HSS tool steel, not a carbide chip.
>
> Or is this just another idea I should forget because I'll not be able to
> hold an edge on the HSS tool because of the impact of its striking the
> workpiece and taking off a thou or less per revolution?
>
> Thanks guys.
>
> Cheers, Gene
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> My web page: <http://coyoteden.dyndns-free.com:85/gene>
> Now I lay me down to sleep
> I pray the double lock will keep;
> May no brick through the window break,
> And, no one rob me till I awake.
>
> ------------------------------------------------------------------------------
> Write once. Port to many.
> Get the SDK and tools to simplify cross-platform app development. Create
> new or port existing apps to sell to consumers worldwide. Explore the
> Intel AppUpSM program developer opportunity. appdeveloper.intel.com/join
> http://p.sf.net/sfu/intel-appdev
> _______________________________________________
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users

------------------------------------------------------------------------------
Write once. Port to many.
Get the SDK and tools to simplify cross-platform app development. Create 
new or port existing apps to sell to consumers worldwide. Explore the 
Intel AppUpSM program developer opportunity. appdeveloper.intel.com/join
http://p.sf.net/sfu/intel-appdev
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Reply via email to