New toy: Setting up Colchester Student lathe

[m_c]

Biggest issue with soluble oils is them going off, but I've never had any problems with my milling machine and I've never changed the coolant since getting it several years ago.

Provided you lube the lathe with slideway oil, any coolant left on the bed will evaporate the water out before anything happens to the metal.
Only place I ever get rust on the milling machine is in any chips that have been left lying for a while, which is more likely to be caused by the dampness in the shed rather the coolant. The same applies to the bandsaw, which never sees any oil.

[Jonathan]

That's encouraging, thanks. I have a dehumidifier in the workshop so that should help evaporate the water quickly. Do you think the coolant I linked to is a good, choice / what did you use?

There are so many to choose from:

http://www.toolbox.co.uk/rocol-roc51...ign=GoogleBase

http://www.rdgtools.co.uk/acatalog/C..._and_oils.html

http://www.ccw-tools.com/prodtype.as...story=category