RC 1/16 M3 Lee - early production tank - build

[Son of a gun-ner]

Louis, don't those Mato plastic gearboxes have a 7mm diameter drive shaft for the plastic sprockets, but those new metal sprockets you've acquired require an 8mm diameter drive shaft

[lmcq11]

Louis, don't those Mato plastic gearboxes have a 7mm diameter drive shaft for the plastic sprockets, but those new metal sprockets you've acquired require an 8mm diameter drive shaft

Oh, i see you might have faced this connectivity challenge before. I noticed the issue this weekend when i made the decision to keep the original gearbox instead of replacing it. The shaft size is actually good, its the groove for the sprocket lock that is deeper on the shaft than on the metal sprocket. This is easily fixed by the application of a brass strip on the groove to make it thicker, and i will need to use a brass tube section inside the sprocket end point to set the spacing between it and the hull. I will show that next as i need to mount the bogies at the right spacing as well.

[Son of a gun-ner]

I would use use 8mm brass tube with 0.45mm wall thickness. Cut to the required length, then cut the tube lengthwise, folding a flat either side of the cut to form the required D shape, and trimming off any excess formed by reshaping from one or both of the cut edges. That way, you only have one piece to pack out the sprocket.
Alternatively, the single cut could be where the round and flat sections meet.
Then the flat portion can be adjusted to suit.

If the flat needs more packing, a bigger diameter tube can be used to make the form if you need to double the metal thickness at the flat, you can reduce the tubes diameter to suit, and gain two longer flats either side of the cut. Allowing you to overlap them. You would only need 10mm diameter tube, as it would give you close to an extra quarter of an inch in circumference, I'm thinking 9mm diameter tube may be tight with only around an eighth extra.

And if you've already thought this, my apologies. I'll leave you alone But I'll keep watching

[Son of a gun-ner]

Oops, I may have jumped the gun, are you saying your metal sprockets and plastic gearbox shaft diameter are the same diameter? Mine aren't.

[lmcq11]

Hi,

My gearbox shaft is 8mm, here is compared to an aluminum 8mm tube. There is a paper thin difference between it and the Mato metal Sprocket hole, but it is better than the looseness with the original plastic sprocket. Otherwise, as you suggested, i would have to use a brass or aluminum tube as spacer between a 7mm shaft and 8mm sprocket.

RC 1/16 M3 Lee early production tank - build

I simply beefed up the flat groove on the shaft, and also put in a spacer for the distance of the sprocket with the hull. it can be adjusted as required. The brass tube between the two sprocket halves is not really required but felt it provides added support.

RC 1/16 M3 Lee early production tank - build

I put the sprocket as close as possible to the hull without touching the transmission cover plate. It will be adjusted later when the bogies and idler situation is determined.

RC 1/16 M3 Lee early production tank - build

an M3 Hex screw is holding it tightly.

RC 1/16 M3 Lee early production tank - build

View with the track on. I especially wanted a Mato M4A1 chassis for this build because of the superb Plastic/metal Mato stock track coming with it. Its quality is way above the Heng Long M4A3 tracks, or even their full metal replacements which i find run like a pig. I have plans to remove the plastic chevron on these tracks and replace with a rectangular rubber pad for a representation of the T41 tracks instead of the T48... but that will be another story.

RC 1/16 M3 Lee early production tank - build

[Son of a gun-ner]

Sorry, I never realised Mato made plastic gearboxes with 8mm shafts

Ok, now you've got very intrigued, somehow I've missed this plastic chassis with 8mm gearbox shafts and especially those metal and plastic tracks. I purchased a metal set of Heng Long tracks to modify a plastic set to get tracks close to yours.
Are those Mato tracks still available?

[lmcq11]

Are those Mato tracks still available?

The tracks came with a deal for the complete lower hull with sprockets, gearbox, speaker and the switch. Got them from Mato Mart last year. When i search the website, they do not show anymore, but somehow they still show in the Mato Mart Point exchange catalog section. Could be an error. They were sold as is, quite cheap so i got 3 of them, but with no return so i suspect they were returns from earlier sales with some issues like bad electronics. They did not look brand new out of the box. But with what i am doing to them, i do not care. You should send them an inquiry. Here's the links.

http://www.matomart.com/prodview.php?p=3660&t=g

Mato mart Sherman hull

[Son of a gun-ner]

Thank you very much

[lmcq11]

This post is for the M3 suspension.

I believe that an effort to represent the early M3 Lee style suspension instead of the M4 Sherman is important, knowing that it will never be perfect. Getting the roller at the right height is critical, the track needs to be flat on the top from the sprocket to the idler. Otherwise, it will not look good.

RC 1/16 M3 Lee early production tank - build

The most important aspect being to show the roller on top of the bogie on a shorter body. There are a few methods available to convert the M4 bogies but all involve heavy crafting and some compromises. Notice the true size of the spring housings on the side compared to the original Shapeways component in earlier post.

RC 1/16 M3 Lee early production tank - build

Its the third time i do this using the Shapeways M3 suspension conversion kit, having used it for the M7 Priest and RAM II builds, Its basic with a bizarre design for the spring housings but its does provide a solid base for RC operations. It needs a lot of modifications to get components to the proper size. It think it could be simplified. Designed for the Heng Long M4A3 bogies, i had to adapt it to the larger Mato M4A1 bogies. After the creation of the prototype, an assembly chain is put in operation for the five others.

RC 1/16 M3 Lee early production tank - build

It took about 6 hours of work.

RC 1/16 M3 Lee early production tank - build

The bogies were heavily modified and reassembled in a lot tighter fashion than before.

RC 1/16 M3 Lee early production tank - build

Here is the Mato M4A1 chassis with M3 style suspension, done on a best effort basis.

RC 1/16 M3 Lee early production tank - build

RC 1/16 M3 Lee early production tank - build

RC 1/16 M3 Lee early production tank - build

Its a dusty operation. Further sanding and fine tuning will be done after the first primer coat.

RC 1/16 M3 Lee early production tank - build

Here is a Before / After view.

RC 1/16 M3 Lee early production tank - build

[lmcq11]

Some comparison between the standard Mato M4A1 and the converted hull. The bogies are narrower by at least 2mm and are installed 1mm closer to the hull like they should be by removing a spacer that Mato added on the suspension mount to align to the sprocket .

RC 1/16 M3 Lee early production tank - build

Capture4.JPG (87.8 KiB) Viewed 5287 times

Alignment with the sprocket is essential, it was earlier moved closer to the hull.

RC 1/16 M3 Lee early production tank - build

Regards, Louis