My shop is plumb full of machinist tools and materials and no rust issues at all. In the summer It's air conditioned and holds 72 day and night and in the winter I run the wood stove which sits about in the middle of the shop, 70 something constantly.
Having literally tons and tons of cast iron and steel in the room helps keep the temperature steady (perhaps more than 30 tons of heavy stuff). It also keeps the place warm for days even without the wood stove, so no problem to take a weekend in the winter and let the shop coast without the wood stove, it'll still be high 60's when we get back.
Grigg
