A constant radius for helix with a conical and cylindrical?

[MAylward]

I'm trying to get a constant radius on a thread form to go from a conical to a cylindrical. The thread grinder tells us that he will climb the conical to maintain the radius but I can't get it to model that way. I'm starting on a conical surface and transitioning to a cylinder. Has anyone found a way to keep a constant tangential radius for something of this nature? Thank you.

Mike Aylward

 

[JohnRBaker]

Can you provide at least a 'picture' of what this would look like?

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA

http://www.siemens.com/plm

http://www.plmworld.org/museum/

To an Engineer, the glass is twice as big as it needs to be.

 

[MAylward]

Thank you for your reply. Here is what I have. The .018 radius follows the thread form. The 1.945 diameter is a cylinder that transitions to the 4 degree conical midway through. The .018 radius has to remain constant and must be tangent at the conical and .025 radial thread form.

 

[pracslipkerm]

Hi MAylward,
For what it's worth... Maybe you could try sketching the base profile and revolving it. Drawing the thread without base edge fillets and draw a helix then sweeping the thread along the helix and filleting the model after thread is swept.


Cheers
Steve Griffiths

If you want to make apple pie from scratch, first you must create the universe!

 

[JohnRBaker]

Could you provide some additional dimensions such as the pitch of the helix and the number of loops (turns) in the thread?

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA

http://www.siemens.com/plm

http://www.plmworld.org/museum/

To an Engineer, the glass is twice as big as it needs to be.

 

[JohnRBaker]

Also, what version of NX are you using? I assume that you're working in Imperial (Inch) units, correct?

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA

http://www.siemens.com/plm

http://www.plmworld.org/museum/

To an Engineer, the glass is twice as big as it needs to be.

 

[MAylward]

Steve, First thanks for your reply. Your suggestion is how it was created. The blend errors out because of what I assume is the transition.

John, I'm using NX6 and Imperial units. The pitch is .073 with 1.5 turns and the transition is .114 after the start of the cone. I've tried several ways to try this with different outcomes. The picture shows one way I did it but the .018 radius is truncated as it follows the form unfortunately that can't happen.

 

[JohnRBaker]

Could you better explain what you mean by "...the transition is .114 after the start of the cone"?

Of course, the actual model (or at least the relevant section) would really help.

John R. Baker, P.E.
Product 'Evangelist'
Product Design Solutions
Siemens PLM Software Inc.
Industry Sector
Cypress, CA

http://www.siemens.com/plm

http://www.plmworld.org/museum/

To an Engineer, the glass is twice as big as it needs to be.

 

[MAylward]

If you follow the link from my post above I have labeled the cone and cylinder. The .114 is from the bottom edge of where the cone starts to where the the cylinder starts. My picture also shows the profile as well.