Hi i have an old bench grinder with no maker or model numbers etc.
It needs wiring from the two wires coming from grinder to the switch,
im unsure whether it would need a capacitor in line somewhere.any
help would be gratefully received.thank you.mark.

A capacitor would not be used in-line. More likely you will need a snubber-capacitor. This is a component to prevent arcing and shorting out switch or relay contacts.