@vjekobalas said: (a)How does one measure and scale the circumference of the wheel eg the red and or black parts ? Do you really want to scale the wheel based on its circumference? Would scaling based upon its diameter be sufficient? For that I would open the wheel component and measure its diameter with the Tape Measure tool. Then enter the desired diameter and hit Enter. Answer in the affirmative to the question about resizing the active group or component. @unknownuser said: (b)If you look at the caster on the side opposite to the breaking mechanism, the base for mounting to the table is extending a distance further out than the circumference of the wheel - how do I measure that distance in case I want to move the base ? I'm not sure I understand what you're after. Do you want to change the dimensions of the mounting plate? It is common for the caster's mounting plate to extend beyond the edge wheel like that. @unknownuser said: (c)If I need to delete the base and the short cylinder on which it rests, how would I add another cylinder and different base so that they are properly centered or off-center as needed (having trouble with alignment and moving eg a square base to center it on a cylinder) Just draw in the parts. Centering shouldn't be any problem because the person who drew it left the center marked on the top of the caster fork. If you have to make a lot of changes to the component to make it suitable for your use, perhpas it would be easier to find a different caster component or just draw your own from scratch.

Jean Lemire - thank you very much ! - I've got it now. It seems to me that it takes a while to go from making a rather mechanical usage of the tool to creatively thinking how to do certain things - I'm not by any means there, but I feel I've got a sense for what is needed to be creative and efficient with the tool - now back to practicing and asking more questions .