Get hold of vs take hold of

Get hold of/take hold of :

a)If you are talking about physically getting/taking hold of something they're the same, though get is slightly more informal. So : You take hold of this end of the table and I'll get hold of the other.
b) But only get hold of can be used in the sense of contact : Get hold of David and tell him about the meeting. You can also get hold of an idea : I don't know where you got hold of the idea that I was American.

Catch hold of :

This is perhaps less usual. For me it implies getting hold of something very quickly. Catch hold of that cat before it gets up that tree!

Grab hold of : (note the spelling)

Again, this implies getting hold of something quickly and suddenly. It can be used to mean contact/talk to : Try and grab hold of Helen before she goes into the meeting and also for an idea you're really committed to : She grabbed hold of the idea of reorganising the department, and nothing we said could make her change her mind

Thank you very much Dear Susan 53 for your time and attension.