Cynthia i dont see why you cannot run 220v on an extension cord. We did it back in SA where all the power is 220V.
Same for the UK.
I would go as far as to say its probably safer than 110V for a simple reason.
Here is a very simplified explanation of the issue.
Machines motors require power to work. Power is measured in Watts.
The basic formula (not precise for other more complicated reasons) for power is P= V X I where
P is measured in watts
V is the voltage
I is the current drawn by the motor.
(just remember what i listed this is simplied in fact its Direct Current Power but for illustration purposes it will do).
so say you have a 1KW requirement. 1KW = 1000 watts
therefore
1000 = V X I
In the case of 110v
I = 1000/110v = approx 9 amps of current
In the case of 220v
I = 1000/220v = approx 4.54 amps
So the higher the voltage the lower the current for the same power requirement. When you come to running an extension cord the issue that always causes a problem is the fact that people tend to overload an extension cords ratings. Putting a higher current through a underated extension cord causes it to heat up and potentially start a fire when that heat gets to the point of softening the plastic insulating coating.
But you also have to consider the quality of insulation. Typically these insulating materials will be way over the 220V rating.
There is difference between powering a machine with 220v and 110v but it would take a lot of complicated calculations to determine and would be specific to each machines specific motors construction and in my view the differences would end up being pretty small.
Something that does not come up often as a suggestion here is that you might consider is to install what i believe Americans call a pony panel. I call it a sub panel.
Have a decent sized cable run from your main panel out to your shop with a main breaker installed in the sub panel. Then put all your shop circuits on that sub panel. That way you can have whatever you like in your shop. Not the 3 phase that Stu refers to but certainly 220V.
The 220v in your shop is not complicated to do. Most houses are on at least 2 phases. Each phase is 110v. So all the electician does is run a wire from both phases.
In my view Glassman should (with the help of the books available at the
HD both their electrical book and the
local code book) be able to do this electrical for you both. You are permited in Ontario to do your own electrical on your house provided you have it inspected by the ESA (electrical safety authority). I found my ESA guy to be very helpful. For the straight forward recepticles etc its not complicated. Just be weary of the HD guys for advice. I got a local electrician in but he advised me to do it myself. The job was not really big enough for him. But for a couple of hundred $$ he did provide me with some good general advice on things to ensure etc.
The costly part is really all the materials but at the end of the day its not complicated to do. Its not as if you are putting in 3 way switches and wiring up switchgear.
Its more just a matter of time. But i should mention i have had Electronics or Electrical Engineering education and worked with electricians both contractor types military types in my past in SA and Canada.
I still dont see why people shy away from it. There are certain basics which are outlined very well in pictures in the HD books and you just have to read the codes and the basic code book for your region is pretty straight forward for what you want to do.
Best of luck.