How to apply a varying fillet on a complex curve [loft]?

cameron_mcknight_macneil

I am recreating a belt sheave from a historical (1909) hand drafted drawing. Where the curved spokes meet the hub there is heavy filleting. Image below:
The original drawing specifies a different curve for each side of a spoke where it meets the hub, as seen in the image below. Problem areas circled in yellow.


Question: is there a way to apply a different 'fillet' to each edge here? right now the modeller treats them as a single edge because they don't intersect anything else.

Or a fillet with a varying radius?

Or some other way to draw this?
After doing some more reading it looks like a loft is the way to do this right now in OnShape. See below:

Now what I'm having trouble with is how to get the loft to go to a single point at the midpoint of the edge to avoid a self-intersecting body.


Thanks,

Cameron.

ilya_baran

Just an idea: have you tried the conic fillet option (in fillet)?

cameron_mcknight_macneil

Thanks for the suggestion. Playing with conic seems to allow me to change the shape of the curve, but not vary the radius.

mahir

I tried reproducing your issue, but I don't see the same problem. I think your spokes are just a touch thinner than your center hub. Because of this, there is not an actual "point" separating the two sides of the spoke at the spoke/hub junction. It's probably just one long tangent line. If you take a look at the model I recreated, if your spokes are the same thickness as your hub, Onshape seems to have no trouble applying two different fillets of varying size to the two different sides.

https://cad.onshape.com/documents/57acdfaae4b005c413ed9b6f/w/3fd585a46d3af1b3ba413c53/e/320547ab844f214e90595be2

cameron_mcknight_macneil

Mahir, thanks for encouraging me to go back and check that obvious thing! The plane for the sketch was slightly inside of the outer radius of the hub, and so the taper of the spoke meant that it was narrower by the time it broke through the surface. Thus, it was the single line.

All fixed now, thanks again!