Who knows the answer

[ryan_618]

When I was a carpenter (before I did electrical) we used 19.2" centers for joists fairly often.

 

[Smart $]

too many cubits ...

The definition changes with the context of the word's usage...

Webster's Revised Unabridged Dictionary (1913)

Cubit
(n.) The forearm; the ulna, a bone of the arm extending from elbow to wrist.
(n.) A measure of length, being the distance from the elbow to the extremity of the middle finger.​

 

[iwire]

There is also a "Royal Egyptian Cubit"

The "Royal Egyptian Cubit" was decreed to be equal to the length of the forearm from the bent elbow to the tip of the extended middle finger plus the width of the palm of the hand of the Pharaoh or King ruling at that time.