Tapered thread creation and one other question.

[BiPolarMoment]

I've been struggling with this for some time--I already have a finished drawing that the part could be made to but it was using a shortcut such that the solidmodel isn't representing the exact intent/finished product.

First off, I'm trying to cut a tapered thread where the minor and major taper uniformally. I've had trouble getting this to work for both the major AND minor simultaneously. Building (additive) the major off a tapered minor yields the prettiest results except that it results in a minor that doesn't stay parallel to the axis of the thread--like so:

This is only a shortcut though. Realistically it should appear to "step" with each thread for both the major and minor.

If, instead, I cut the thread starting from the largest major diameter I can get the minor to stay parallel to the axis, but then I have two other problems:

1) I can't seem to cut the taper for the major simultaneously or I get intersections along the sweep path--I can live with that, I can always cut it with a second sweep. The problem is that:
2) I can't get rid of some artificial surfaces where the sweep cross section is coincident to a surface but not intersecting--I wouldn't have a problem with this either except they show up in the drawing/wireframe:

(note the surfaces on the right--the helix is not tapering at that point, there should be nothing there)

I'm going to try another work-around to eliminate the surfaces, but I'm open to suggestions. I'm using SW2006 BTW.

 

[BiPolarMoment]

The "other question" would be about those surfaces created--I didn't really segregate it in the post.

Measure tool assures me they are intersecting but the visual displays otherwise.

 

[BiPolarMoment]

Result of my shortcut:

It's not very robust--I took the first example and cut the minor deeper.

I'd still like any help on how I could have done this in one step.

 

[Russell67]

What you need to do is to create 2 helixes both starting at the same point, rotating in opposite direction. Then do 2 swept cuts along the helixes and then do some adjusting to get the look you want. With cutting the material out it has a better chance of blending. How do you post pictures with your mesages.

 

[Eltron]

Russ, check faq559-1100.

Dan

http://www.eltronresearch.com

 

[Stugots]

http://tinypic.com/view.php?pic=5xpbptv

Stugots
Mechanical Designer
SW '06 SP5.1

 

[JamesBarlow]

Another thing I do is pretty simple.

Keep my fingers crossed that SolidWorks will one day catch up with Solid Edge on the creation of external threads, including tapered pipe threads.

Of course this doesn't help me now, but hope springs eternal - or something like that.