Carrier armour manufacturer?

[rob love]

I had to straighten some of the front shields on my 105 howitzer due to rollover damage when they were in service. They will often have those hammering marks as well. The press will only go so far before you hear a "crack", and sure enoguh, there will be a crack in the armour. I ended up heating them red to bend them straight, likely destroying the temper on the hard side. If there is ever a next time I'll try the hammering method.

[Lynn Eades]

The process must have been done by a machine. those marks are too deep and too consistent to be done by hand. The skill probably came in, in knowing where to hit.

[Bob Phillips]

I just checked the archival collection for SDA at the Cambridge ( formerly towns of Galt, Preston & Hespler) and they have tool catalogues back to 1900 or so but nothing that I see in the WW2 era. They certainly made nice handsaws which are now very collectible...I agree that the marks must be machine made are they strike marks or clamp marks ?? BP

[rob love]

I also lean towards a hammer press of some kind. Otherwise those guys would have arms like popeye on spinach by the end of an 8 hour day swinging a 3 pound sledge that many times.

[David Dunlop]

Interesting topic. The manufacture process history I am familiar with relates to getting the Canadian production of the UC sorted out, including the issue of warping armour plate. British carrier production would predate Canadian by a few years. Does anyone know how warping plate was dealt with in England?

Also, did the same problem show in Australian and New Zealand production and if so, how was it dealt with there?

Might as well throw the whole bag of carrots out there for us to nibble on. T16 production in the USA. What did they do to solve this problem?

Possibly a common solution for each location. Maybe in Canada the problem was finding the right company with the proper equipment to handle the job rather than finding the technique?

David

[Lynn Eades]

I would say strike marks Bob. They vary in their concentration but not in the way they are done.
David, British carriers used armour plate that looks like the smooth pattern you might see on sand that is levelled by gentle water action. A fine ripple pattern that was easily hidden by a coat of paint.
The Australians I believe developed their own bullet proof plate (BP2) As i recall production was held up for a while with welding it. I think stainless rods were at least the interim fix. I think the need for stainless rods was overcome during the Australian and New Zealand carrier production. Hopefully someone more in tune with Aust. pattern carriers can verify this.
My British built and welded hull AOP carrier (mid 41) was welded with stainless rods.
The un answered question I have is that some British built armour, (the heavy daimlier armoured car as an example) is made with the Canadian style "axe marked" armour plate. How did this come about? Was Canadian plate supplied to British industry?

[rob love]

I think the same axe marks can be found on the ferrets, but I'll have to look again to confirm. Doubtful the UK would have emported the steel from us at that point, and as well there is no SDA markings.

[rob love]

Here are the three pages from the design branch records re bullet proof and armour plate development in Canada. If you open them in a new tab you can expand them to a readable level of magnification.

[Michael R.]

Tank u Rob

[Richard Farrant]

Originally Posted by Lynn Eades

I would say strike marks Bob. They vary in their concentration but not in the way they are done.
David, British carriers used armour plate that looks like the smooth pattern you might see on sand that is levelled by gentle water action. A fine ripple pattern that was easily hidden by a coat of paint.
The Australians I believe developed their own bullet proof plate (BP2) As i recall production was held up for a while with welding it. I think stainless rods were at least the interim fix. I think the need for stainless rods was overcome during the Australian and New Zealand carrier production. Hopefully someone more in tune with Aust. pattern carriers can verify this.
My British built and welded hull AOP carrier (mid 41) was welded with stainless rods.
The un answered question I have is that some British built armour, (the heavy daimlier armoured car as an example) is made with the Canadian style "axe marked" armour plate. How did this come about? Was Canadian plate supplied to British industry?

Hi Lynn,
After many years of being around British armour, I have noticed that those plates on Daimler hulls, Dingo scout car, Armoured Car and Ferrets, that have a cut out for a flap or visor, etc are those most likely to have the hammer marks. This I believe is because the plates were machined and cut before the hardening process and some distortion may have occurred. The plain plates with no cut outs do not seem to have the marks, generally.

The welding was done with Nickel Chrome rods, although stainless may have been used in later repairs. The process of welding armour was pioneered by Guy Motors for their armoured car, but this vehicle was later produced by Humber.

Nothing to do with Canadian steel manufacturers or lumberjacks wielding axes!

regards, Richard

[Lynn Eades]

Richard, Rob's post states the use of Austenitic rods. My understanding is that this type of stainless steel contains both nickel and chromium. To my simple un educated mind that is stainless.
I went to a chaps place some years back and he (along with a complete running Dagenham built AOP carrier) had the remains of another AOP carrier. It had been part of a sea wall. All he had was the spider web like welds of a silvery material that I would call stainless steel.
I could easily recognise the (some what collapsed) shape of the carrier welds.
Other Kiwis will know who I am talking about.

As an aside there were 79 of these Ford of Dagenham built Armoured O.P MkIII w (welded hull) carriers that came to N.Z. Later, 40 went to Tonga. I don't know if any of them returned. allowing for two other hulls we can account for 5 of them from that batch built in mid 1941.
What ever the welds are, I could not cut it with the gas but it certainly came away nicely with arc air gouging.

[Petr Brezina]

Interestingly enough my british Mk.III had been welded with non-austenitic rods - all welds are as rusty as the rest of the hull.

[Richard Farrant]

Originally Posted by Lynn Eades

Richard, Rob's post states the use of Austenitic rods. My understanding is that this type of stainless steel contains both nickel and chromium. To my simple un educated mind that is stainless.

Lynn,
We had a thread going on this armour plate welding rod subject about 3 years ago. I quoted then from a WW2 REME welding manual for repairing armour (even has details regarding German armour) and the rods were austenitic armour plate electrodes, comprising of 18% chrome and 8% nickel, the coatings contained special substances for welding armour plate. It is true that stainless steel rods are of the same percentages as above but to quote the manual " if armour plate electrodes are not available welding may be attempted with ordinary Stainless Steel electrodes."

So to answer you question there was a difference between Austenitic Armour rods and plain Stainless Steel ones when they were building these vehicles.