TongDe M113 becomes an M113 A1 G/M of the German Armed Forces

[jhamm]

Hi,
my next Project...
This is my retirement gift to myself.
Ordered from Ali on 2 September, the parcel delivery service finally delivered the slightly larger box from China 5 weeks later.....
Inside was a TongDe M2412-C M113A2 APC.
I immediately unpacked it and got it ready for a test drive.
After only 5 metres, it was undriveable!
I took the instruction manual and looked up the command to switch speeds: press the T button and pull the right stick.
That worked, but something was rattling – the tracks were much too loose...
So I hoisted it onto the workbench:

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The operating instructions state that in order to adjust the guide wheel, it must be removed so that you can access the screw for the swivel arm behind it...
Who on earth came up with that? Coolbank solves this problem much better, see the Crusader.
Loosen this screw by only about 2 turns so that the swivel arm is released from the gearing and can be turned.
Turn the swivel arm one notch and tighten the screw again, then screw the guide wheel back on.
Under no circumstances should you loosen the screw any further, as there is only one nut on the inside, which is held in place with hot glue:

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Let's see how long that lasts.
At least nothing is rattling anymore and the ‘box’ drives reasonably well, even if not in a straight line...

The next thing I looked at was the driver's hatch, which has to be swung to the side to get to the ON/OFF switch. Again, the question is, who came up with this?
On the original, the hatch swings back.
So, one bold cut with the side cutters and the hatch is off:

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With 2 mm poly and a 2 mm shaft, the whole thing was rebuilt to be more realistic:

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That's better.

Then unscrew the ‘box’ by removing four screws from the underside:

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The gearboxes act on external axles with a gear:

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I find the counter bearing a little ‘delicate’, to put it mildly, and here too I wonder how long it will last.
On the other/right side, the gears only overlap by 50%.......
The area in front of/above the gear is open – even when the top part is in place!
Here, sand, dust, dirt, water or whatever else gets whirled up by the chains, almost like on a conveyor belt, and gets in...
You can imagine the rest.

During the test drive, the door in the tailgate kept opening... I stopped that for now with a piece of poly:

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Then I attached some add-on parts, everything that will be painted over later anyway.
Here's a look at the tailgate:

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I still had the piece of wire rope left over from Lee.

Initial conclusion:
TongDe could have put a little more effort into it, especially since Coolbank offers technically superior models at better prices.

That's all for today.
Thanks for watching and see you later...

[Estnische]

Good luck with your M113 project - I guess we are discovering what Heng Long have found out in their longer life span. Still, it gives us plenty of scope to make them better.

You will find the rear door handle works perfectly like the original if placed in the correct location. I don't understand why TD did that.

[jhamm]

Good luck with your M113 project - I guess we are discovering what Heng Long have found out in their longer life span. Still, it gives us plenty of scope to make them better.

You will find the rear door handle works perfectly like the original if placed in the correct location.

Wait for progress...
I will update the build report.
Everything you see in the first post is already two weeks old.
There ist a lot to do...

[jhamm]

The next part...

The M-113 was allowed to do a few laps at the club meeting.
To check it out, I took another look at the drive axles...
That doesn't look too good for just a few minutes of driving:

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The small Ø 7 mm ball bearing is held in place by a pressure piece – or so we assume.
However, the axle can tilt – it is loose – because the bearing is not clamped.
The reason for this is that the pressure piece cannot clamp the bearing because the two holes (which go over the pins) are not deep enough.
The two 4 mm pins are also so soft that even when the bearing is clamped, the pressure piece gives way.
Here is the pressure piece:

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The pressure piece also has the task of holding the two gear wheels on the output shaft of the gearbox in position, but it is too narrow for this.
As a result, the overlap of the gear wheels is only 50% in some cases:

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Before something worse happens and the brass gears on the drive shaft wear down or get cavities, a solution must be found.
Ultimately, it will be a solution from the 3D printer.
So, we put our heads together, measured everything and drew it all out.
Voilà, the result:

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This part does everything in one:
- it presses the two bearings into their seats
- keeps the gears at a distance
- covers the gear on the output shaft
- fits exactly into the front trough and provides additional support

Another annoyance are the two retaining screws for the gearboxes, which are located directly next to the chain in the chassis.
Although these screws have rounded heads, they protrude a few tenths of a millimetre into the chain and cause it to rattle constantly....
Now you could countersink the mounting holes and insert countersunk screws – if it weren't for the glorious designer of the gearboxes – what an idiot.... :ah
The two threads in the gearbox housing each run exactly into a gear – so you mustn't use countersunk screws that are too long,
otherwise the screws will press against the gear inside and the garbox will stuck.
So, only M3x4 countersunk screws may be used, and the hole must be countersunk so that the screw head is flush with the surface.

The prototype is printed:

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It looks pretty good so far – except for the stripped hole because I used a Phillips screwdriver that was too big.
The following changes still need to be made to the part:
- The part needs to be lengthened so that it fits snugly between the cheeks.
- Improve accessibility of the screws.
- Better cover towards the gearbox.

I measured the distance to the bottom of the chassis and modified the part so that it could be screwed to the bottom of the chassis.
This proved to be very helpful.
The part has increased slightly in size and volume:

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To ensure that the part fits perfectly, the two sprues on the bevel must be removed:

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The part fits really well:

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Drill through the bottom of the chassis using a 2.5 mm drill bit:

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With a Ø 3.2 mm, drill only the bottom of the chassis and screw the part in place from below:

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It holds! The small original screws in the Ø 4 mm plastic posts did not hold....

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That should hopefully conclude the chapter on gearboxes and output shafts.

[jhamm]

Another significant weak point needs to be addressed – the attachment of the track tensioner.
As a reminder:

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The M3 screw is held in place from the inside by the nut – the nut is ‘professionally’ secured with hot glue, and the cables have been glued in place as well...
Long story short, here's the solution:

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A fitting piece with a self-locking nut pressed into it.
This allows you to loosen the screw by 2-3 turns, turn the chain tensioner as desired, and nothing falls off or needs to be held in place.
The fitting does not necessarily have to be glued in place, as it fits precisely into the recess.
The cables for the rear lighting will later be laid invisibly in the upper body.

Then two more parts for structural stability, so that the wobbly lower hull gains rigidity.
The first part supports the gearboxes in relation to each other – the gearboxes are only screwed to the 1.5 mm side walls:

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And a base plate for the rear section:

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This makes it almost impossible to twist the chassis.

[jhamm]

The M3x4 countersunk screws I ordered have finally arrived...
Installed them right away:

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Now the chains no longer rattle...

Then I installed M113 idler wheels from AFV-Modell.com
This requires quite a bit of effort and is not something you can do in a hurry, because the brackets have to be machined:

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Looks better...

Now to the first new part printed.
The gunner's hatch:

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A lot moore will following...

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[jhamm]

The front plate is now also finished...
Splashboard with functioning hinge mechanism as on the original:

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But now let's continue with the printing madness...
It's really fun to push the printer to its limits:

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But that's not all...

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A little later – the printer had been busy:

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[jhamm]

...and many hours later, many parts have been printed and assembled:

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This unspeakably fat magnet and its holder will disappear...

Not many original parts of the upper hull have been preserved.
But if you want more details and are building a specific design, then sometimes that's how it turns out.
That's the current status.
Next, the rear tailgate will be worked on – with the lever in the correct position and functioning properly, of course...