I recently had a small part a cylinder 1/4" dia x 3/4"lg  with a .125 radius on one end then shelled to 1/16" wall thkness.(worked great) then I recreated it and did a revolve spin with a polyline same shape but  when I did a shell 1/16" wall thkness it  did not shell properly The shel[ the inside with like a hole out the flat face I picked to shell. I guess I am wondering do revolve spin shell differently than a 3d cylinder why would this not shell properly?

Is the Spin profile "closed"? An open profile creates a hollow object and the Shell tool wants a solid object.

It works for me as open or closed spin or cylinder in every TC version I've got ranging from V10 to 2016.  You've made an error somewhere, without an example file there's no way to tell what it is.  You're using a mix of decimal and fractional measurement and a random mix of techniques, but consistency is a good start, and good practise generally.  You're describing a hemisphere cap on a cylinder, with a void  within.  Lots of ways to do that in TC.   

If the profile was open, applying Create Solid>From Surface to the result will allow it to Shell properly.

Henry H

I tried it again created a new file on my other computer not my laptop and it did shell fine. I don't know why  it is not shelling like it should on my laptop but I think your right I have made an error somewhere.
Thanks for all the help. I am thinking it is the polyline?? But I thought if the polyline was open you couldn't create a solid???

TC Pro has two types of surface: TC surfaces, which are meshes that don't do curved surfaces, surface booleans (shelling, filleting, chamfering), physical properties even if they're manifold volumes and some other things, like snapping to the centre of mesh cylinder ends.  TC's other surfaces are ACIS surfaces, which do allow those things, and others as well.  ACIS also has some capacity to repair some faults, like stitching open seams such as occurred with some older programs that produced IGES solids from faces, and the capacity to make a solid from a surface even if it has missing faces, if those faces are planar.  So if you drew a quarter-circle arc and single line polyline and revolved them to create a hemisphere on an open cylinder, select it and modify|modify 3D objects|create solid|from surface and that's what you'll get.  SAT healing does the same thing.