Economies of scale in Panzer production?

[stg 44]

Assuming a what if of sorts, how much economies of scale could the Germans experience by producing just one major panzer chassis from 1938 on? I was having a discussion about how it didn't make sense to have both the Pz III and IV chassis considering how close in weight they were, so if they just produced the Pz IV (considering how many issues with the Pz III they had until 1938) could they expect greater total output than the sum of the Pz III and IV historical output? How about later when things like the Pz V and VI roll out and there is competition, but one main chassis below them?

[Dann Falk]

The Pz III was the Main Battle Tank
The Pz IV was the Support Tank

Two tanks, two missions.
To do what you said would require a change in Panzer doctrine/tactics. Not likely.

[stg 44]

The Pz III was the Main Battle Tank
The Pz IV was the Support Tank

Two tanks, two missions.
To do what you said would require a change in Panzer doctrine/tactics. Not likely.

Humor me. Say they kept it to one chassis with different armament to different missions.

[Dann Falk]

OK...

Pz III Combat weight in 1939-40, 20 tons - production until 1939 = 351 units
Pz IV Combat weight in 1039-40, 23 tons - production until 1939 = 503 units

If we compare just weight/steel, not producing the PZ III would yield enough steel for about 305 more Pz IVs, for a total of about 800 Pz IV in 1939. These two vehicles did share common components, so maybe switching production really could yield the extra 305 Pz IVs.

The major issue from 1936-39 isn't so much different production lines, but allocation of resources and the desire/need to produce more tanks. Everyone wanted their share of the available steel, copper, rubber, aluminum and so on. Producing more tanks = fewer subs or artillery or trucks.

[stg 44]

Is that combat weight empty or filled with ammo and fuel?
Wouldn't there be efficiencies caused by production scale that allows them to use the same steel to make more units?

Edit:
https://de.wikipedia.org/wiki/Panzerkampfwagen_IV
The weight of 23 tons wasn't reached until after 1940.

[Dann Falk]

I was taking the weight from the book, German tanks of WW2 by F.M. von Senger und Etterlin 1969. The production numbers from the book Panzer Truppen Vol 1, 1996, Edited by Thomas L. Lents

The table says Combat weight, so the dry/empty weight would be less, but the ratio would have been about the same. I was using an average weight for the two tanks for simplicity.

The limiting factor was not tank production capacity, but steel production. If you have 20 tons of steel to make a Pz III and try to make a 23 ton Pz IV tank, you are short about 3 tons of steel. That extra steel must come from somewhere. That is why I said the steel for 351 Pz III could produce about 305 Pz IV.

You are correct that economies of scale can boost production, but only if you have unlimited resources feeding into that sector. In the years before the start of WW2, I believe Germany has excess tank production capacity, but was limited by lack of resources. Germany could only produce so much steel each year and the army decide to use their allocation of steel to produce the type and number of tanks, vehicles, and weapons they did. Boosting tank production means less of something else.

[Christian Ankerstjerne]

The amount of steel present in the final vehicle does not reflect how many raw materials were used to build the vehicle. The amount of iron used to build a tank appears to be around 1.5 to 2 times the weight of the vehicle. More importantly other resources, such as aluminium, does not appear to change significantly as the vehicle grows larger. Subcomponents, such as engines, guns, optics, ball bearings, assembly crew time, and tank crew training, will not change significantly either as the vehicle grows larger.