Find Helix Angle = f(pitch, or height & revolution) 1

[kenapacki]

For a milled cutter, I am given the specification of 10 degree helix angel (angle to the axis of the cylinder).
In Solidworks, I can only define the helix in terms of pitch; or height and degrees of revolution.

How can I determine pitch when given the helix angle?

I cannot find the answer in Marks Handbood or Machinery's Handbook,

http://www.eng-tips.com,

http://www.engineers.com

Thanks for any pointers you can give me.
Ken Apacki

 

[Kapitan]

Hi Ken,
If your cutter diameter = D and your Pitch Angle = A then
the pitch will be;
P = Pi * D * Tan(90-A)
If the the cylindrical surface of the cutter is developed or unrolled into the flat then the helix becomes a right angled triangle whose base is the circumference and the height is the pitch.
The helix angle is between the hypotenuse and the height.
Cheers,
Dave

 

[prex]

p=[ignore]&pi[/ignore];Dtan[ignore]&alpha[/ignore];
where D is the diameter at which the angle [ignore]&alpha[/ignore]; is to be measured. prex

http://www.xcalcs.com

Online tools for structural design

 

[CoryPad]

The posts by kapitan and prex may seem contradictory, but this is due to nomenclature. According to ISO 5408, Cylindrical screw threads - Vocabulary, the lead angle &[ignore]psi[/ignore]; is the angle between the inclined thread and a perpendicular plane to the thread axis. Thus,

P = &[ignore]pi[/ignore]; &[ignore]middot[/ignore]; d₂ &[ignore]middot[/ignore]; tan &[ignore]psi[/ignore];

where

P is thread pitch (assuming a single start thread)
&[ignore]pi[/ignore]; = 3.141 592 654
d₂ is the pitch diameter

prex shows the same equation, with &[ignore]psi[/ignore]; = &[ignore]alpha[/ignore];

The helix angle is the compliment of the lead angle, so kapitan's equation is correct assuming the terms helix angle and pitch angle are identical.

 

[kenapacki]

Thank you all.
Your answers are very clear and I have my answer.

Strange that I couldn't find this in the mechanical handbooks.