"The day that the planners said, "oh crap, we're in trouble and need to step up production" is not when war time production started. That simply indicates that the emphasis shifted towards 'total war' production, something which really only Germany and the Soviet Union did. Labelling anything an a scale less than 'total war production' as PEACETIME paints a non-aggressive picture which is simply not accurate. "
I am not sure how various countries compare on "Peace Time" Vs "War time" production.
For example the Russians may not have had a third shift working at the tank factories in 1938-39 but they managed to build well over 20,000 tanks during the thirties, more than the rest of the world put together and then some. A feat made possible buy the notable lack of truck or car production for a country of it's size. Even tractor manufacture may have been secondary.
How much of Russia's GDP was going to it's Military during the "Peace time" of the late thirties?
Going from Peace time to war time is more than a matter of saying "Oh, crap, time to shift" if you do that it is too late. Adding a second or third shift is easy but for the quantities of war material used in WW II you needed new factories, steel mills, ship yards and so on. You even need to establish priorities in rail traffic and shipping space.
the British "shadow" factories were planned and built before 1939-40 and small groups of experienced workmen were taken from existing factories to act as a core and to train the new workers.
the Americans had 2 years to build completely new factories and still went on to vastly increased the size of their factories and build completely new ones inland in case of bombardment or long range bomber strikes.
Some american car factories didn't convert over to war production, instead they were shuttered and the work force transfered to new, specially built factories more suited to war production. In some cases they used their tooling to make parts under sub-contract. For instance it was estimated that Allison only made about 1/3 of the engine in house. 1/3 was made by Cadillac, Buick and a few other GM divisions and the remaining 1/3 came from over 800 subcontractors.
Maytag washing machine company used their casting facilities to make aluminium castings for Packard Merlins.
that is the difference between peace time production and war production. A country might spend double or triple the amount on weapons in 1938-39 than it did in 1933 but until the civilian goods and services production or usage is stopped or limited in order to further military production you don't really have "war production".
While the US didn't resort to drafting workers into factories I would say it came pretty close to total war production. Underfed, forced labor isn't really going to give the production rates that that better treated workers will. There was also a fair amount of cottage industry going on in the US. Small 2-10 man shops in garages or basements using old machine tools to build parts under sub-contract. My Grandfather worked in a 4 man shop making gyroscope parts under subcontract to Nordon. Much of the machinery was run by over head pulleys and belts. Company owner got gas ration coupons for his Piper Cub to fly the parts out to speed delivery. Shop was located about 1/2 way up the coast of Maine or over 400miles from the Nordon factory. No they didn't fly all the way

But the roads were none to good in Maine at the time and the plane helped get the 50-60 miles to a better place to ship from.
