Many thanks for all the replies, you've come up trumps, I will buy one of the suggested paints now.
I didn't want to repaint the whole drill but touch up parts to improve it's overall look.
I have added a split pin through the depth gauge threaded rod at the maximum travel point of 3 3/4" as if the nuts are inadvertently wound higher the teeth on the "Activating gear & shaft" gear can become damaged when they run out of teeth on the quill.
I know this as I had to file one of the gear teeth back into shape on my drill.
Edited By C J on 07/02/2018 15:16:10