Nice dead dog!
Actually, chain the dog so that he can't get into the shop is one thing.
Another is to keep the door closed to the shop, putting on a closer if
necessary.
Get a electric fence transformer and hook it up to the bench (metal top
please) and turn it on when you leave the shop AND remember to turn it off
when you arrive at the bench. Window screen on the floor (dual chore of
picking up swarf and grounding the dog) will quickly teach him about not
going to the table or other such locations. Even a small tool on the floor
will teach him to not do that sort of stuff.
If the dog really is persistant, then it is time to get rid of it.

--
Bob May
Losing weight is easy! If you ever want to lose weight, eat and drink less.
Works evevery time it is tried!