Trouble sweeping

[inflame769148]

Hi all, I'm having a lot of trouble with this shape ( just a rough sketch here from win paint ). I made it from circles touching each other then added the straight line and delete arcs not needed.
I want to sweep it along a helix inside an open cylinder then subtract it from the cylinder to leave the form of a plastic thread. Yes, the thread is rounded.

I tried multiple times to get the lines to join, using join and polyline edit but the curve in the middle would not join until I redrew it as an arc.
Now that they are joined, an attempt at sweeping gives me the error : Cannot sweep or extrude a self-intersecting curve.

Who can help ?
cirles 8.jpg

- - - Updated - - -

Sorry should have mentioned using Autocad 2016

[inflame769148]

Here it is.
Anyone ?

plastic thread 2.jpg

[inflame769148]

So I tried creating a simple 2D object to "sweep" with and that doesn't work either.
I just don't get it.
I have used sweep many times before without issue on shapes like a circle or square, but....
Here I have an arc and three straight lines all connected at the corners. "Edit polyline" or "join" will not make them as one object. For some reason the three lines will become as one but the arc keeps being rejected.
What's going on ???

Attachment 106823

[bruce.jones542083]

"Self intersecting curve" errors usually show up under one of two conditions, something in your profile is overlapping the rotation axis or the spline or polyline is doubled back on itself. to solve the first, trim both ends of your profile against the axis. To solve the second select the profile and explode it. Select (crossing window) each part of your shape, check for the number of items selected. If it should read one selected and instead it reads 2,3 or more, delete the extra lines or arcs. don't forget to rebuild your spline or PLINE. You might also try performing your sweep outside the primary part, then insert it and Boolean subtract.

[seant61]

Is this the ultimate goal?TwistCap.png