Metallic composition of Tower handcuffs

Gentlemen,
Does anyone know what the Tower handcuffs are made of? Was the plating chrome or nickel? When I first started collecting I was experimenting with a pair of leg irons and was able to break off part of the bow. I didn't use that much force. I associate that with pot metal. But surely they had to be steel? But if steel, would I be able to break off part of the bow? I now treat Tower products very gently. 
Mike

Hey Mike. Here is a page from a 1894 Tower Lyons Catalog. On here, they just list their cuffs as being made from "forged steel." They are nickel plated. As far as the steel being brittle, i do not know the cause? I did the exact same thing you did, but it was on an Adams cuff. Snapped the tail of the swing, right off at the very bottom edge of the cuff's body.
-Richard Knip-

That answers everything Richard about the metals. Thank you. But I wonder if the steel in those days had bubbles or something that caused very weak spots. I don't think steel gets weaker with age, does it?

The lock mechanism should be treated with care on Towers due to age and usage. The body of the lock is a cast steel and should be sound. The bows were drop forged and this would have also hardened the material to hold it's shape. There is not much tolerance for the bow to pass thru the lock and a misaligned bow would be annoying. You would never know if this has happened to a cuff and been rectified by anyone in the past. The structure of the bow is likely to have been fractured at some time and any new attempt to reshape it cause it to saddening and surprisingly break. By looking at the ends of the break, the darker areas (oxidized) are signs of the old fracture and new shiny crystallized areas are the new break. Fear not, handle and enjoy.

Thank you.