You have a spool cabinet and it is what you said...a cabinet for spools of thread. These are very collectible.
In 1864, George and William Clark built a thread mill in Newark, N.J. and it became Clark Thread Co.
O.N.T. stand for Our New Thread which was coined by George Clark for this 6 strand thread.
It would help if your friend can give you a history of the piece. The oddity about your piece is that it has "spool" and not "spool cotton" on it. To help determine age, can you please pull out a drawer and take a picture of the inside of the drawer and the back of the piece. Please advise if there are any splits damage to the cabinet or drawers as well. Can you please describe if the fronts are glass or metal plate with the wording on them.
