With respect Hopper, I would advise not using WD-40 as a machine-tool preservative; certainly not the basic, original "WD-40", which is the product most widely available.
Despite the claims on its own labels, that is as its initials say, a water-dispersant. It is also a good solvent, but not a good lubricant or lasting preservative. Its SDS shows mineral-oil and paraffin-wax dissolved in white spirit, and the environmental advice thereon shows what experience with it suggests, that it breaks down fairly easily and quickly.
It is good for cleaning machines, once all the abrasive dirt has been brushed off, but with caution as it will wash out but not replace the oil in slides, etc.; and its anti-corrosion protection does not last very long.
Use it to clean the lathe, then wipe it all off and protect the bare metal surfaces with lubricating oil or grease – or for long-term storage, a preservative wax that can be removed with white spirit. (As used by our machine-tool suppliers.)
There are lubricants available under the WD-40 brand, in similar packing, and it's worth looking at the manufacturer's catalogue, but original WD-40 for long-term protection of machinery? No!