VICKERS MK6B's resto

[Mike Cecil]

The originals were probably formed using a die set in a hydraulic double-action press: the first part of the very slow stroke clamps the entire sheet flat, the second part is the actual forming die that stretches the material to shape. The clamping before forming prevents the sheet from wrinkling around the edges and away from the forming die.

It always amazed me just how far the right material can be stretched - deep stainless steel wash-up sinks, for example, are/were done this way.

Amazing work, Colin. Very, very skilful.

Do you have an original .50" Vickers ammunition box to use as a sample?

Mike

[Bob Carriere]

....... Eventually when I tackle the restoration of my CMP trailer I will need to do similar indentations, in a sun burst fashion, on the front head board of the trailer box........ now I know how.....

When is the real issue !!!!!!

How did you resolve the warping that resulted from the stretching of the sheet metal????? my piece will be narrow but long...about 30 inches x 80 inches...... 14 gauge..... top edge and side ends will be prebent in a double return box shape.......at a fabricator and will add stiffness.

Cheers

[colin jones]

Thankyou Mike and Bob, I could have mostly eliminated the warping by making a different bottom die. I should not have just done a narrow perimeter form as that is what created the warp. Instead it should have been the full size of my pressing area as that puts the same pressure everywhere. I guess I was just a bit slack really . The better way would have been to mill the shape I wanted into a thicker piece of metal as that would cover all areas or plug weld a laser/plasma sheet on the top. Either way it was just lack of support and I knew it would happen but being aluminium it is easier to shrink and stretch.
This is a problem when using bead rollers as that too creates stretching. As I am no panel beater, YouTube is a valuable source of information but I used a rubber mallet to shrink and stretch the material. Not as easy task on steel. The dies I made to press my bottom engine covers were heavy and pressed the entire area of the covers so I got very minimal distortion.
The wire rolled edge certainly stiffens it up and I clamped the whole thing down before I formed the edges. I learn a bit more each time I make things like this.
Oh, and Mike! No I don't have any .50 Vickers ammo boxes�� unfortunately and would be very happy to do a deal with anyone that has some�� Please��

[jack neville]

I can recommend Mikes advice Colin. Sandwich the ally between two plates, secured by any means and you will get no warpage. I did this tool box lid for the Walker Bulldog resto project that Weapsim did for the Cairns tank museum.
i couldn't get enough pressure at 100 tons in one go so had to step it along.
Still came out neatly.

[jack neville]

Hope you dont mind the intrusion Colin.
Unlike most following this thread I was lucky enough to have seen these Vickers tanks in the flesh before any work was undertaken and the sheer amount of creativity and brilliance going into these projects has been nothing short of outstanding.

[colin jones]

Hi Jack, no I don't mind at all. I am quite familiar with fully clamping prior to pressing and have done on a few like that on different projects I was having a slack attack🙄 and have to modify that particular die set to press another smaller door with a smaller inset then I will de weld and use the steel elsewhere. It was quite a while ago when you saw these tanks in their raw state
It has been quite a road to get them here but I have enjoyed the many different challenges as they occur. There has been many parts I have made to only throw away because I wasn't happy with them. Of course I never posted those pics And like most, I have spent ridiculous amounts of time on some thing that are totally hidden and then look back and wonder why? knowing full well you would do it again. I know I should have spent more time on these and done it that way. I still have a few more to do so I will make the dies with full clamping and well done on the pressing you did there

[colin jones]

I had to make some smallish type handles so I thought I would show how I got them as a exact tee easily. A small bloc of steel with tow machined grooves as per the pictures. Once clamped in the vise and hammered down they have no option but to be equal. Saves some guess work. I also had to backtrack on my work by removing the rear cover, fuel tank and shelf. I decided to fab a complete new rear shelf for the tanks as after another inspection of the ones I made a couple of years back, I wasn't happy with them, All good now.