Thanks everyone. The problem is the vacuum gauge is only showing about
6 inches mercury, so the table may be leaking. My delay in replying is
because I've decided to use a tank between the pump and table, i.e.
empty the tank, release a valve and woosh (hopefully) as air leaves
the table. My tank (OK my pressure cooker) now shows 16 inches
mercury which is the best I've got so far. Cannot get a release valve
til Monday but does half an atmosphere seem sufficient?
Has anyone a better idea for a home made vacuum tank?
Evacuated