During World War II, Germany constructed many armored vehicles using a system of interlocking plates. This is visible at the seams of armored vehicles. The welds are not a straight line, instead the edges of the plates are complementary "teeth" which fit together. This then allowed the teeth to be welded together.

If you look at the following photo of the Jagdpanzer 38, you can see this design along the front of the hull. This particularly design was produced for a while after the end of WWII, but the system of interlocking plates did not appear in any new designs. Why was it not used after World War II?

enter image description here

Credit for image: https://en.wikipedia.org/wiki/Hetzer#/media/File:Jagdpanzer_38t_Hetzer_TMFM.JPG

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    I'm going to guess that welding techniques got better. In modern welding the weld is stronger than the metal.
    – Schwern
    May 21, 2017 at 2:01

1 Answer 1


Actually, according to Richard Ogorkiewicz in Jane's Technology of Tanks (1991), interlocking armour was used in later tanks and light-armoured-vehicles.

In the chapter on Armour protection he notes that stepped joints were used in the American M-551 Sheridan light tank (entered service in 1969), the British Scorpion light tank (entered service in 1973), and the French AMX-10 tracked armoured-infantry-vehicle (also entered service in 1973). [p368]

It's perhaps worth noting that the references to stepped armour here are in the context of aluminium armour. Ogorkiewicz states that:

... aluminium armour is easier to machine and the greater thickness of its plates makes it possible to use stepped joints, which provide a partial interlock between plates and require therefore less welding.

I'll see if I can a copy of the reference online.

EDIT: The reference is available on Internet Archive. I've added the link above.

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    Don't the interlocked plates need more welding due to the zig-zagging of the weld line?
    – DevSolar
    May 22, 2017 at 12:23
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    @DevSolar I would have thought so too. I defer to Ogorkiewicz's expertise though. Perhaps interlocking plates don't require full-depth welds as they're already locked together in one plane? I did try looking up details for the Scorpion, but apparently a lot of the details are still classified. May 22, 2017 at 12:32

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