a friend / client of mine gave me a hint (thanks AB !) which lead to me quiring a batch of 1K70's.
I am currently checking how good they are working by setting the double lock.
Then holding them with the movable bow down.
And unlocking them with a key.
Most of the cuffs open without a problem.
Gravity's force is enough to make the bow move.
On some few one the key does unlock the double lock but does not seem to move the teeth far enough for the bow to swing freely.
Maybe a wrong key.
Or maybe just tolerances due to wear.
I'd like to try another original key.
Plus maybe try with one or two prison keys to determine what I have.
And then see that I can either get original keys.
Or find blanks that can be made into working keys.
If someone is willing to lend me a key...or two...or three...or maybe sell one : Gimme a holler please.