WW2 German tank factories - assembly line question

Imagine changing the tracks during the Battle of the Bulge.  I found an After Action Report for the month of January, 1945 from the 740th TB (this was the unit which had to scrounge armored vehicles from a depot to go into combat) which was directed by Command to change to the steel tracks on January 1 due to slippage on icy and snowy terrain and roads.

   Wow that is fast, I have never done it but I know there is a ton,( no pun intended), of work to do. I imagine if your off by just a pinch setting the pin could be a real bugger. 

armornut

    Bish, given the weight of the tracks, any mechanical advantage is helpful. I don't doubt it is heavy work in a clean factory, can only imagine trying to re-track your vehicle in a foot of mud or at 20* below.  Think I'll stick to my 35th stuff LOL.

 

I once lost a track in the middle of a massive rubbish dump just outside Basra, that was fun

Its not to bad in the garage if you know what your doing. Me and 2 of my mates had it down to 1hr 20min for changing both tracks which included building the new one.

    Bish, given the weight of the tracks, any mechanical advantage is helpful. I don't doubt it is heavy work in a clean factory, can only imagine trying to re-track your vehicle in a foot of mud or at 20* below.  Think I'll stick to my 35th stuff LOL.

Knight, as armor said, i am pretty sure thats the track. If your are lwering the hull onto the track, it would make sense to do both at once. You can see on the right side that the track is also laying flat and has not been connected.

I would imagine there is some sort of guide to make sure the tracks are laid out so the hull can simply be lowered onto it.

armor, thats how we used to do our tracks.

    Not trying to start an argument , I think what you are seeing is the connecting rings and track pin, if you look at the other side there does not appear to be a jig, there should be one there to if your observation is correct.

    To also add to my post earlier, after the tank is set on the tracks the drive sprocket was sometimes used as a capston to bring the top run through and the the mechanics would attach the two ends together. Sorry for any confusion, and again not trying to start an argument.

This is what I am referring to as a jig. The red arrow indicates the raised guide which is precisely where the guide teeth of the track would run. You can see how it sets spacing, as well as how it brings this side of the hull without tracks on it to a point where it is level with the side that had the track already installed. Look closely and you can see where the surface has become discolored from the road wheels running over top of them during production runs.

All a pretty "big tolerance operation". The jig, and for sure that looks like one, would be useful to roll the wheel into position, as well as hold it up where it needs to be. Not like taking the space saver spare on the Toyota and holding it on your knee.

I use jigs a lot on the bench. For putting 72 1/100 scale cannon carriages at 9 parts each together. No way to put wings on a biplane without one.

These pictures seem to me cleaned up. Absent all the stuff you'd expect like gas hoses, barrels, tools, work lights and wood dunnage to put parts on.

KnightTemplar5150

There is a 90 degree surface placed against the outer face of the road wheels, parallel to the hull.

I think that what you're seeing here is actually the outermost road wheel of the leading set. Remember that the wheels were interleaved and each roadwheel station had a double/single arrangement which alternated (ie. station 1, II-I, station 2, I-II). What you are seeing is the outermost wheel of station 1, with the paired wheels of station 2 behind. 

Busy, take a look at the right side of the image (left side of the hull seated in the driver's position. There is a 90 degree surface placed against the outer face of the road wheels, parallel to the hull. Under the road wheels is another part of that 90 angle which sets the spacing of those wheels. There is another 90 strip welded to that surface, just where the guide teeth of the tracks would run. 

The wheels are, as you point out, bolted to the torsion arms. But, as a production guy, I can testify that jigs are commonplace fixtures in production at this scale. This job sets spacing, which could be affected by over/under tightening of the leg nuts and/or flex in the torsion bar system.

Knight, i can't make out which bit you are reffering to, i can't see a jig. The wheels would not need anything to keep them straight as they are bolted to the axel arms.

Ixion

 

 

In the lower image, I can't help but notice the jig being employed on the right side of the hull to keep the road wheels running straight and vertical. It appears to have been used often enough that the wheels have worn a distinctive pattern on the bottom plate. That's a great detail for a diorama, but it may also be a handy tool to have on the bench for building scale Tigers in the future. Nice find, Ixion!

GMorrison

Leaving it on the crane doesn’t make sense. Putting it together on blocks does, like any other “hull”.

The factory only has a small number of overhead rail cranes, but would be building dozens of vehicles at a time.

Sure the crane might well come back and pick it up to move to final assembly.

 

If you look at Ixion's pics you can see the hull is on a carrage with small rail road type wheels, Ixion does point that out. The crane would only be used to lift the hull onto the tracks. Once those are fitted, the vehcile can be moved on those.

And whats also interesting is that the hull is fitted to the tracks before painting.

That excellent photo also shows a crane being used to lower a prime mover into the hull. That would not be feasible if another crane was supporting the hull.

Id guess the tracks were installed and the vehicle was set on the erection floor before the turret was installed. One photo seems to suggest that.

lifting a Tiger with its turret on would require the heaviest kind of cranes.

Ive seen pictures of T34/76s flying around on cranes, but that’s much less weight.

Leaving it on the crane doesn’t make sense. Putting it together on blocks does, like any other “hull”.

The factory only has a small number of overhead rail cranes, but would be building dozens of vehicles at a time.

Sure the crane might well come back and pick it up to move to final assembly.

The hull would have to be lowered, or towed, onto the tracks as it can't move by itself until they are fitted. The former makes the most sense.

KyleBragger

Actually - is it safe to say that the hull has wheels etc. attached while still suspended on a crane, then is lowered, wheels/sprockets and all, on to the laid out tracks?

The hull would not be attached to the crane while the torsion bars and wheels were being installed.The torsion bars, wheels, sprockets and idlers would be added to the hull while it was on the rail-mounted carriage, along with the engine, transmission, etc., then the entire assembly would be lifted onto the tracks laying on the floor;

Thank you to you both for the quick & detailed replies!!

After the machining for the torsion bar holes, final drives, turret ring and other smaller holes are completed, the hull is moved through the factory on a rail-mounted carriage for final assembly. You can see the stock-piled torsion arms and road wheels on the right.

About a third of the way down this page are a bunch of Henschel factory floor photos of Tigers in various stages of production;

http://histomil.com/viewtopic.php?f=338&t=3918&start=820

    The hulls were moved about the factory via overhead cranes, similar to todays steel mills, usually parallel to the long outer factory walls with a "main street" down the middle.

     Once the lower hulls are welded the are moved onto lumber cribbing which supports the lower hull while the torsion arms, road wheels, return rollers, idlers and drive sprockets are attached.

    At this point the engine, drive train, and upper hull are welded. The tracks on the heavier tanks, Panthers, Tigers, ect, are laid out parallel and at the correct width. Then using pullies and cable the tracks are pulled over the rear idlerusing the drive sprocket as the power. When the two ends meet mechanics pinch the linkes together and install a pin that traverses the the entire link. Tank drives out of factory.

    Hope this helps and Happy Modelling.