helix (or something)?

[yack_ass]

Hi guys!
I have a problem. I need to draw a piece (of what I do not know) and it isn't anything particularly difficult to do. But for one thing. A helix (or somethnig like that). I hope you can help me.


I've searched with google to find some tutorials (I found them for drawing "gears") and I did find a couple of tutorials with helix in the name, but nothing came close to what I need (at least that's my oppinion --> correct me please) If somebody knows how to draw this please help me.
(I use CATIA V5R16).



Here are some more pictures for your enjoyment.



p.s.: I apologize for my english, it is a bit rusty (nothing that a little WD40 can't fix )

 

[MrCATIA]

It's difficult to understand the exact shape of the screw feature you're trying to model. Based on the pictures, it appears the OD of the screw is not circular (not constant radius), and it appears the screw thread profile is also not constant. Do you have any prints for reference? Or maybe take some pictures showing the front, top and side views of the part?

You are on the right track about a Helix. The basic steps to create a uniform screw are:

1. create a Helix to define the pitch & length (the path) of the screw
2. create a Sketch of the thread profile
3. make a Rib, with the sketch profile swept through helix curve

 

[yack_ass]

I figured out, that this "thing" on my part is actually a worm.
Do I proceed the same way as I would with a helix (the thing that bothers me is the fact, that the radious changes)--> Do I have to use the "spiral tool"?

 

[MrCATIA]

You definitely want to use a Helix to define the 3D path of the "worm." Try using the Profile option to vary the radius.

A Spiral is a planar (2D) version of a Helix, so you don't want to use that.

Do you have any dimensions or diagrams that describe the shape of the "worm"?