Das Wettringer Modellbauforum

Hallo!

My name is Joël and I live in Paris. I'm really sorry to be unable to write in german but however, I hope you will enjoy to share this project.

I'd like to scratchbuild a 1/24 scale model of the US Army M1A1 wrecker, also known as Kenworth 573 or Ward La France serie 5. After the WWII, a lot of theim were used by french fire brigades. One was owned by the Paris Fire Regiment untill 60' years. I have found some pictures: in front of the headquarters and in action during a railway accident. You can see that it was improved with a closed cab and some particular details.





Load capacity scheme and technical manual TM 9-796 will be very useful documents to lead this project.



An interesting time of the job is the selection of components: rims, axles, Evergreen tubes and strips, diamond pattern plates. I'll describe theim in detail for each step of the building, which hard polystyrene will be the main material.



Let me show you the first part of my work: a strong frame is made of brass U profiles of 10mm and 8 mm. The drawing is the lubrificating chart, extract from TM 9-796 and printed at the good dimension.



See you later

Official pics from TM manuals let appear many differences between genuine olive drab model and the red one!





See you later

An other interesting view of the "CG 2" in the center of the Paris fire regiment headquarter building:


That's all, for this week end!

Hello and many thanks for the members who have replied with friendly messages!

I suggest to speak about wheels, which are so important for the realism of the model, and necessary to adjust many components as axles , suspension springs, or later, bodies.

M1A1 wrecker run on 11.00x20 Non Directional Tires, which tread is very famous and tipical of the WW 2 US trucks. Unfortunatly, I only know 2 good reproductions in 1/24 scale:
- Half-track M3 tin-plate model of KADEN (former GONIO) uses too small 9.00x20 tires.
- Some tires I bought many years ago in a swepmarket, probably issued from an IMAI kit of US 155mm howitzer.
.

Each tire is made of black vinyl and comes in 2 parts: the main which reproduces one side and the rolling surface, and the opposite side:

If these tyres are very interesting due to the name of a famous manufacturer , they are too small to figure 11.00x20. After many reflexions and calculations (which I'm not very proud...) I decided to operate a esthetical surgery to obtain the master I will use later for a silicon moulding.
The first step consist in turning a bone (in white resin on the picture) to correct the diameter of the tyre. The tyre is cut with the Chopper to obtain a perfectly perpandicular section. The missing section represents 2/30 of the circumference and will be taken in a identical tire. The reason of this step of 1/30 is the number or teeth of the genuine IMAI tire. At the end, my tyre will have 32 teeth (It seems to have 35 in reality) and a correct diameter.

Let me show you the final result in a next message.

The problem of the rim's masters is easier to resolve: 6 holes 20" rims exist on a diecast 1/24 model from ERTL, Chevy 55' stake truck.


Rims have been turned and modified with KFS resin parts (item TQ 18: Trailer Disc Brake Kit) to obtain 10 screws rims. Rolling bearings caps are not in place yet.

I hope to show you the results of my chemical experiences next time...

See you later

Hallo!

Some news after several week of work (and holidays too...)! Many problems occured and the main was that my silicon paste (or catalysator?) was too old and refused to polymerize.

The casting of the master tire was not so easy and it was impossible to obtain a straight result due to the deformations of the genuine tire.

I decided to mould two "half tire" in polyurethan resin and to turn each part before assembly theim together.

The center of each face is adjusted in order to be filled with a genuine vinyl center. After that, the two sides of the tyre are glued with epoxy cement, according a great care to the good repartition of the treads.

You can see the result, front and rear wheel masters nearly to be casted: tyre is made of polyurethan resin, sides are used as they come from IMAI kit (may be I could use this particularity to do white edges tyres ?).




Rear rim lip needs to be thicked again, but the tires have now the correct diameter (44 mm) and the manufacturer markings have been preserved and will be read on the final wheels.

The brass frame is now fitted with 4 front suspension springs supports, rear bogie support and rear bumpers.

.

My next job will consist in creating springs from Evergreen strips.

See you later!