I proceeded with the hull fabrication. I used my angle blocks and got the main part of it done:

Then I addes side panels from copper as I had some lying about. Much body work and filling to be done later but its OK for this stage.

Then I approached the fenders. These are an issue as they are curved and feature a long lip along the length of them.

To make them I got two strips of steel and joined them lengthwise at right angles.

Then simply trimmed off the excess with a Dremel and sanded smooth. Before and after above.

Normally I would use some skinny brass angle soldered on but this has been problematic before with curves as the brass kinks when curved.

To deal with the curves, I used a jewellers saw to make some notches in the lip near the curve. 

Then I bent the fender over  a steel bar and the notches closed up along the curve. A bit of bondo on the gaps will finish the job nicely I think.

Here they are in place on the hull upper.

P

The swing arms are simple....some slices of a centre drilled 8mm steel rod with flats filed on them and then silver soldered to some 4mm silver steel rod.

The wheels need bearings...I am using needle bearings as they are more forgiving if you cannot drill extremely precise holes. I used a 7.9 mm drill bit, drilled out the wheels and pressed in the bearings.

p

I need a suspension system and will be making two racks that will hold the mechanism.

Here they are laid out on the lower hull prior to fabrication.

The rotation of the axles will rotate a lever in the rack which is connected to a spring.

Here I make the off center rotation bit using the proxxon and some brass bar:

Th eaxle will go through these and then the brass will be cross drilled to hold the leve which will engage the spring.

I needed a slot to engage with the spring and made these by simply chucking the lever in the drill and filing the slot:

Then I silver soldered the bits together:

And the result were these:

These will then fit in the racks like this:

Here are the racks in place:

And here are the finally assembled suspension system racks:

I like to retain the option of a moving tank so onto the motors. I am using big chuncky 200 rpm right angle motors from Ebay. One on each side.

I need a bracket to hold two of them back to back so I fashioned on from brass bar stock.

The motors will be connected by chains to the drives shafts so I needed a means of tensioning and slacking the chains. I mounted the bracket by a t-nut, accessible from the hull underside, and used two long M2 bolts as a means of adjusting the position of the motor bracket on the slide of teh base plate. Which can then be fixed using teh t-nut.

Here it is in position:

The drive shafts are held in place by a central moount with needle bearings and two hubs (one on each side) both holding needle bearings. The shaft is 8mm silver steel rod.

Here with the chains in place but slack:

And now tight. I had to move the sprocket position to the interior as the chains were fouling on the side walls of the hull.

And here is a little video of the runout on the axles after all that faffing about.

https://youtu.be/P6-QlHSSHvc

Not so bad.

p

Now I needed a sprocket for the tracks. There is no one suitable available so I have to make one.

I calculated the chain pitch from the distance between the pins on the track. And used some formulae I got from the net to work out how many teeth I needed for a sprocket of teh right diameter.

And then wasted a lot of material trying to file in teeth by various means.

It was not going well at all. 

Then I finally got a method of drilling teh appropriate sized holes along a circle corresponding to the pitch circle diameter and opening out those holes with a burr mounted in the proxxon. A flap disk in the dremel served to smooth things out a bit.

And the tracks fit very nicely indeed.

I then need a means of letting the axle engage with the sprocket. The simplest is a D shape on the central bore but I dont have broaches. 

So I made some silver steel inserts like these:

When soldered into the bore of the sprocket then provide a D shape on the back.

This is what a flat on the drive shaft will enage with.

The turret needs attention next.

p

The turret was always going to a pig. I made some measurements and sketches and cut a bottom and top plate. These were joined together by some threaded bars to hold them in the right orientation. Then I simply "wrapped" steel sheet around this and soldered in place. Looks like a total badger but this is just the subframe.

This is the turret with a new top plate on to hide some screws and a rudimentary mantlet and gun. I thibk the asymmetry has been reproduced enough to keep me happy at least.

I then did some work on the body. The grilles on the vents of the engine deck seem to range from chicken wire to rebar depending on what pictures you look at but I used some brass bar and it will have to do as it was a pain in the rear.

Then I just started adding bits and pieces to try and flesh out the details. Not everything is accurate....but I don't care at this point.

Most recently I slapped some acid etch on the lower hall and started test fitting all the bits.

With a 4000 mAh battery in there things are very tight but thats OK. 

And then I test fitted all my road wheels:

I have to now start making all the hubcaps to try and hide the screws and things.

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Thats alot of work to do. I realy like the idea tho. I will be watching this one. Is this going to be an RC version? You are doing a great job so far. 

Pretty amazing work!  I take it you are a machinist?  Thanks for posting - this is really fun to follow along.

I cannot pretend to be machinist.....Im a chemist by trade.

Ive thought of buying a lathe once or twice but I have neither the room or the skill for one.

I test fitted some tracks today....some final bits to attach to the hull then its time for a scrub with a snading sponge and some acetone and then a coat of primer before final assembly.

almost too pretty to paint

Thanks for sharing this amazing build. It's amazing what you have accomplished with simple hand tools and a small drill press. I've learned a lot looking at your creative solutions for building complex mechanical assemblies like the suspension system. Thanks again for sharing your skills with us and enjoy the rest of your build.

keavdog

almost too pretty to paint

 

Yeah I'd almost want to leave it natural metal to show off all the work you did there! 

Great show!!! 

Progressed towards final assembly today.

I dont like painting and it is only ever done to match other tanks I have and cover up scabby bodywork which was th ecircumstance here.

Primed it and sprayed on a few clumsy coats of gun metal paint  then started putting it together.

No real issues there. Noticed a few mistakes underway but do not care in the slightest!

Motors went in fine, greased up the bearings as I went.

I dislike having to undo screws and such to charge batteries and so so I mounted a box under th erear hatch that just squeezes in between rear hull and motors. Into this I mounted a set of banana ports and a fairly high amp switch. I will wire these into the tank when I get around to the electrics I guess.

I have been avoiding the wheels as they lack hubcaps but that has to be done next and I am not sure how I will tackle those.

Thats coming along great. I realy like your charging posts. I will have to remember that setup. I have done alot of RC vehicles if you have questions just let me know. 

Impressive work and fun to follow along.

Ben / DRUMS01

Looks flawless, I'd swear it were a commercially available kit instead of scratchbuilt.

Love the idea of putting the charging port and switch under the engine access cover.

Finally wrapped up construction. All thats left is a headlight lens but I have no plastic to make one.

I take my holidays next week so will attend to electrics and so on after I get back.

Really glad this one is done. It was a real tiny tank and they are a pain.

And to put its petite size in perspective...here it is beside a Soviet U-19 and a Japanese Type 5.

I have also been busy with my next tank and will put a thread up as soon as I am ready to start.

Thanks for watching!

P

So cool.

That U-19 is an odd looking beast.