Diamond pattern with multi start thread

[JY`S]

Hello,

I am looking for help for the attached print.I am not sure how to figure my feed on this. It does not give me the pitch,but 1.5 deg. lead per rev. I am machining this on a cnc lathe. I tried the 1.5 as the feedrate with 20 starts. A G32 that feeds in and back (to create the diamond pattern) out in one pass 20xs. I do not think this is the correct feedrate. Any input will be GREATLY appreciated! I can send the print to anyone who thinks they could help. It will not let me Attach the print. [email protected]

Thanks,
Jason

 

[angelw]

Hello,

I am looking for help for the attached print.I am not sure how to figure my feed on this. It does not give me the pitch,but 1.5 deg. lead per rev. I am machining this on a cnc lathe. I tried the 1.5 as the feedrate with 20 starts. A G32 that feeds in and back (to create the diamond pattern) out in one pass 20xs. I do not think this is the correct feedrate. Any input will be GREATLY appreciated! I can send the print to anyone who thinks they could help. It will not let me Attach the print. [email protected]

Thanks,
Jason

Hello Jason,
Its a simple Trig calculation (TAN) to determine the Lead. Given a constant angle, in your case 1.5 degs, the Lead will vary, determined by the Diameter. Accordingly, if you calculate the Circumference of the part, you have one side of a Right Triangle and an Angle. Give those two components of the triangle, you can easily calculate the Lead of the Thread. It also depends on how the drawing was dimensioned with regards to the 1.5 deg, as to whether the Lead Line of the Triangle is the Opposite or Adjacent side of the Triangle. In any case, its not difficult to calculate.

I believe you will get a speedier result if you just Post a sketch of the part, or at least the details of the part diameter and how the 1.5degs is dimensioned, ie. from the Axial Centre Line, or from the Perpendicular to the Axial Centre Line.



Regards,

Bill

 

[Ox]

1.5* lead @ 20 starts?

I hope the part D is in the 20" ballpark!


I think you will get the same result by stuffing it through a centerless grinder...


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Think Snow Eh!
Ox

 

[Bobw]

I was going to share my experiences.. But no print.. No follow up.. I've
been there and done that, but I need some info first.

And 1.5 degree lead, like OX said. So fine even a record player needle
couldn't pick it up. Unless its on something pretty big.