Hey Pete,

I don't think there is much you can do "for free". You'll have to
spend something, no matter what you do.

Free isn't necessary. Safe and effective are my priorities.

And it doesn't really take much. The metal does not have to be
"warm", but just warmer that the dew point in the shop

Ceiling fans help considerably. Just left on, directed over the
machines, it will help a lot.

Cover the machines loosely with something that will hold some heat in,
like a blanket or cardboard box. Then put a light bulb underneath. If
you can put a thermostat (garage sale tops 5 bucks) in line with the
bulb. It will help, but note that most thermostat's won't "set" to
below 50 degrees or so.
If you do so, two hints.. use good "Rough Service" bulb(s),...and
either a "cord light dimmer" which cuts the lamp output to about 1/2,
or a lamp dimmer that allows even greater control.

Quartz-halogen lamps might fix the major problem I have, which is the
burnt-out bulb. It still has the "visible from outside" issue.

Thanks!
Pete