David,
It can take a long time for a machine to start expanding or contracting due to ambient temperature, due to it's mass.
I put an oil filled rad in my shop, and it is on permanently to raise the ambient temperature. It took a couple of weeks before the machines stopped feeling like a block of ice, they still feel cold compared to smaller tooling even now, and that is after six weeks. I suppose the same thing would happen if I turned the rad off, the machines would work like storage radiators for quite a while.
John