Create Depression / Concave / Remove material from Surface - Bike Aerobars

trihardert

Hi All,

Apologies if this is a stupid question... but... I can't work out how to remove material from the top of an extrude.

I'm trying to make some new aerobars for my TT bike that can support the entire forearm. I've created sketches for the top and side profiles. Then I extruded the top and removed from the side via a new surface.

I'm now left with a uniform but wavy 'flat' surface that has varying widths.

What I'd like to do now is concave the surface to allow the forearm to sit into the depression comfortably, around 10mm at its deepest point. But I can't figure out a way to do this!

Ultimately, I'd also like the underside of the bars to have a little more of a leading airfoil shape, but at the moment I've filleted it (but want it to be a sharper profile) – again, I can't seem to work this out!

All this leads me to the conclusion that I'm probably approaching this whole project from the wrong point of view!

Any help much appreciated!

https://cad.onshape.com/documents/2cbd5941905be8c3dc2c1374/w/4d4b9d4a4eb4ea5a3bc9f62f/e/38ae6c8abaa5bd51bc8b86ca

Cheers,

Tom

trihardert

And here's a pic so far!

matthew_stacy

@trihardert, what if you start by modeling the surface where arm meets arm-rest?  Then thicken that.  Does that achieve the effect that you are pursuing?

If so consider creating a FILL surface using a sketch tracing your top-view-photo and one or more guide curves to provide the depth.

https://cad.onshape.com/documents/2c470e60997277da2a4acf98/w/d8a778d365396771a5bddb3f/e/55a70ca43ab3565b1f70873b 

I hope that helps.

trihardert

Hi Matthew,

Thanks so much. I've not used the fill tool at all before but it looks like it could be just the ticket! I'll have a try and see how I get on.

Thanks again,

Tom