Chuck Guard

We have a chuck guard on the museum's Smart & Brown model A which has a microswitch added and it works very well. It saves my back when switching off the lathe and everyone who uses the lathe has to use it with no exceptions, after all this is in a museum, not a private shed, and we have to pay at least lip service to H & S.

My BLE 330 type small gearhead lathe has MT5 spindle for collets and it can do 1650 rpm .
My lathe chuck guard is only a perspex type one, no metal. I did made some other guards fitting to toolpost, which I fit as needed.
Nowhere they indicate the speed limit of the 3 jaw chuck that came with it. Does anybody know their 3/4-jaw chuck speed limits-? (Compared to collet speeds).

My Sieg C6 came with a clear plastic 'chuck guard'. I don't know whether it's purpose is to guard operator against unintentional contact with the rotating chuck, or to guard the operator against things flying off the rotating chuck. Either way I would not want to use my lathe without it. Not only does it prevent loose bits of swarf flying into my face, it also prevents cutting fluid from creating nice patterns on my clean shirt, and is a great reminder to remove the chuck key before switching on. The only times it has been a nuisance is when holding a large odd-shaped item in the 4-jaw, which wanted to hit the guard every revolution.

By contrast, my 1929 Ideal does not have a chuck guard and has more than once caught me 'off-guard' resulting in a painful whack on the finger on knuckle. Fortunately the only time something more serious happened (caught the sleeve of a jacket on a corner of the object being turned) the slip in the flat belt drive was a sufficient safety clutch to prevent the rest of my arm from feeling the effects of a 500RPM lump of heavy metal. If there was an easy way of adding a chuck guard to my old lathe I would do it. As an alternative I am looking at a large clear plastic shield on a movable arm that can be moved into or out of position as needed.