spacing two spheres using a tube

[mbostonsprint]

I have an application where I need to be able to construct a tubular spacer with a specific ID, that will keep two spherical lens surfaces at an already-determined distance. Ideally, I could work from the two coaxial lenses (they have flat surface on the back) and draw something on the flats, but none of the projection commands in sketch mode seem to work the way I would imagine (projecting through the material to the other surface), and I can't sketch on the spherical surfaces. If I could figure out to get a circle on the spherical surfaces, I think that would make this easy to do.

I can conceive of a couple of different approaches with cylinders, but it seems like a lot of steps to do to solve what otherwise seems like a simple problem. Suggestions welcome.

[robduarte]

I suspect there's an easy solution to this, but I'm not 100% sure of what you're looking for. Can you scribble a sketch on a napkin and post that?

[Jon.Dean]

Hi Matt,

A simple sketch will make much clearer as to what you want to achieve.

Jon.

[jeff_strater · Accepted solution]

This is kind of a shot in the dark, but maybe it will be close to what you are trying to do.

The basic idea is to make the cylinder larger than the distance to the spherical lenses, and use Split Body to trim the cylinder to fit the shape.  I probably have some details wrong here, like the orientation of the flat side of the lenses, etc.  But hopefully you can extrapolate from this:

Jeff Strater (Fusion development)

[mbostonsprint]

Jeff,

Thanks for the guidance. That looks like a process concept that will work, although my end result needs to be a line contact only, basically the ID line of a cylinder (square-cut on the ends) in contact with the spherical surface. I should be able to figure out the extra steps to cut the cylinder as needed.