Jubilees clips, top and bottom of the mould hold the outer sheet in place and finally the whole assembly is bolted together.

The polyurethane, release agent and vacuum chamber are all currently in bound, all I have to do before commencing the casting is to shot blast the hubs and add some extra bands around the outside of the hubs to increase the surface area so that the tyres have a bigger area to bond to.

Confused join the que.

Jon

Great work you are doing. I am planning to have a go at doing a Vickers light tank or a A13 cruiser tank, have the fabrication skills and tooling but you try finding the drawings with measurements, thats the hardest part in my book, at the moment i am doing a lot of homework. Trips to Bovington are very trying as theres always one measurement that you forget to take. Keep up the good work.

Have you given any thought to adding vanes or fins to the hub to key into the "body" of urethane? Not making any claims that they should be there, but they would reduce the propensity for the urethane to shear off the hub. Fine line, of course, as too much would reduce the elasticity and absorbtion of the urethane.

Morning Chris,
Have you got the two Black prince Books on the A13, I am a bit anal but they are, in my opinion, fantastic books and contain a mountain of technical detail. It might be worth mentioning your project on the HMVF forum. The other source of reference is a good quality model.

Regards,

Jon

Morning Toni,

Thanks for the reply, I not sure what you mean by vanes but my intention is to weld a couple of bands, either of flat steel of 5mm dia bar, around the circumference of the hub to act as anchors. Many years ago I had the job of turning the rubber tyres off of some forklift wheels and when the rubber was removed, it revealed a series of small V grooves machined into the hubs circumference for this exact purpose, I could go down that route, I am not sure yet.

Regard,

Jon

Like the cleats on steel tractor wheels.

Hi Jon, i have got the P.M Knight books on the A13, gives a really good account of the construction details of the tank. A tank often seen in 1940 used in France and the Western desert and here in the UK but only one left, A French museum scrapped one not that long ago :fry: I have also bought a good quality model like you mentioned but it will be a tape measure job to proof scale the sizes. As for drawings i am finding it difficult to find anything really especially hull plate sizes etc, i even tried Bovington but the didnt have much. I do wonder where these factory drawings went on most British tanks as its a bit of a mystery, i have asked all over, someone sitting on them.
As for your mould to cast the urethane i have noticed that tank bogie wheels have groves in them or raised steps to stop the rubbers sliding off, the A13 has them on their aluminium wheels they use.

Tony,

A question that I asked at the time was why have grooves around the circumference and not ridges across the hub. Apparently the rubber flexes in the direction of rotation as the wheel goes round, if the ribs are across the hub the ribs cut into the rubber and end up shredding the tyre. Anyway that was their answer and they were in the business, so I assumed that they knew what they were talking about.

Chris,
my hubs already have a lip to stop the tyre coming off but the addition of ribs around the circumference will help even more.

Jon

As the steering box is from a 430 series AFV I needed to add a plug to the front of the hull so that I could top it up with oil.

I decided to add some detail to the front of the hull while I was waiting for the vacuum components to arrive, the small maintenance hatch doesn't open, it's just there for show. The brackets either side. are to wrap a tow steel rope

The locking mechanism for the drivers hatch seems overly complex to my mind but it was interesting to construct.

My version. On the top of the hatch there's a square socket so that one can open the hatch from the outside, I used an old 3/8" drive socket and brazed it onto the end of the main shaft.

On the inside of the hull below the drivers hatch there is a tray that, I assume, holds a rubber seal. I cant find any pictures of the open hatch showing this area, so that is purely an educated guess.

On the front of the hull there are two towing hooks, one either side. On the original tank these had a tendency to brake off, apparently due to the incorrect towing procedure. As I need to be able to use these for actually towing the vehicle, they need to be strong and as I didn't have any material of the correct size available, I decided to modify a couple to tractor towing hooks.

I know that they are not the same profile as the originals but I didn't want to weaken them too much. I anticipate that when the steel tow ropes turn up, the end profile might need modifying in order to get the tow rope eye over.

That's it up to date for now.

Jon

When I worked in a polyurethane shop (Redwood Plastics) back in the 90's, one of the services was rebuilding non pneumatic forklift wheels and industrial drive wheels / idlers. After sandblasting the mating surface of the hubs we would coat the outside diameter with a bonding agent called Thixon, or maybe Thickson. This corrected durability problems with our previously remanufactured wheels. You don't want your wheels to peel their pads.

Good point Mike, I will check with the manufacturers on Monday.

As far as I can remember they said to shot blast, dip in 20% Phosphoric Acid and then ensure that the component is thoroughly dry before pouring.

Jon

Its a phosphate finish its what they use in the gun trade to parkerize weapons or tools and spanners, its also used in the paint trade so you don't have to use a chemical primer. The phosphate process gives the surface a microscopic pourus finish so either oil or paint will soak into the surface, the same applies to using the chemical you are using. Its a simple process just boil up the solution, dip your blasted metal part, wash off, dry with a hot air gun and you are ready to paint, oil etc.

Thanks Chris. :thup2:

Evening,



The steel tow cables and the D shackles turned up, I ordered 18mm diameter tow cables which are each rated at 4.1 tons. There seems to be a number of ways in which the cables were carried on the front of the tanks in period pictures, in fact there doesn't appear to be a standard to how many cables are carried at all. Some pictures show just a single cable, some have two cables, some appear to be about 18mm in diameter, whereas some look a lot smaller and there are even some pictures showing what appears to be some carrying tow ropes.

I decided, in the end, not to add extra bands around the circumference of the hub but instead to machine a series of small grooves into the surface to help the polyurethane adhere.

That's all folks,



Jon

Evening All,

Manufacturing the radio operators seat was next on the list, the only picture that I could find of it is this one and I think that this is a pre-production version but it's better than nothing. This is my version.

It can fit in two positions but personally, I wouldn't want to be in either, as it is so very cramped and how you would get out in an emergency is any ones guess.
I don't think that you can appreciate just how little room there is inside this tank until the upper hull and turret are in place, it must have been hell in the European theatre, I can't imagine what it was like in the heat of North Africa.



That's all for now.



Jon

Hi Jon.

Wow! Snug! I guess if one crew member farted, they all said ‘excuse me’, just to be on the safe side.

Is the Wireless Operator located aft of the turret basket assembly? That would suggest either a rear deck access hatch, or access via the turret, which, as you noted, would be tricky in an emergency with injured crew. Also would not appear to leave much room for the wireless equipment.

David

Evening David,

If you were sitting in the radio operators seat, facing forwards towards the driver, the radio equipment would be on a shelf to your left hand side (shown marked in blue on the attached picture). The shelf overhangs the tracks and is part of the track guard.

The picture of the tank interior shows how tight things were, the radio operators seat would be where the battery is situated in this picture.

There is an escape hatch that is situated above the red arrow but it is the other side of the small bulk head with the vision slit in.

The escape hatch is marked in red. To access this hatch, the radiator baffle plate would first have to be folded forward and then the seat back rest laid flat. Then by ducking under the aforementioned bulkhead, you would have access to the escape hatch. The last picture is the underside of the hatch.

Jon

Absolute exquisite work !

Thanks Richard. :thup:

Afternoon All,

The ammunition for the MG34 machine gun, in the early versions of the Panzer ll, was loaded into saddle drum magazines, these were stored along the hull side behind the driver.
The saddle drums were expensive to manufacture, bulky to store and apparently they had a tendency to cause stoppages, so later models were supplied with Gurtsacs to hold the ammunition. A canvas bag with a steel top, it was still quite complex but easier to store and cheaper to manufacture.

The Gurtsacs were stored in the same area as the saddle drums but the storage method was far simpler to manufacture, being just a horizontal lip that the Gurtsacs slipped over. You can just make it out on the picture below.

The interior picture is from the Tank museums Ausf F and as I have no pictures of the interior of a Ausf C with the MG34 ammunition stored in Gurtsacs I have had to base my work on the information that I have.

Bolted to the upper left hand side of this structure, would have been a carrier for the radio operators gas mask canister.

Two more...……..

I am trying to finish all the components in the area around the radio operators seat. The loading plan shows the gas mask container holder, a water bottle or feldflasche holder ( marked in blue) and a bracket to hold the morse code key (marked in red).
You can see the morse key and the water bottle brackets on these two internal pictures in the panzer ll at the tank museum.