Mack 45 ton switcher

[Chris333]

Over in the TP56 thread I posted about a Mack locomotive body I printed and the thought of using a 6 wheel truck to power it:
https://www.therailwire.net/forum/index.php?topic=42126.msg730762#msg730762

Have since decided to just make my own chassis. Narrow Garage in Japan make a bunch of chassis and even the size I need, but their gear ratios are pretty low. So using their parts I came up with my own. On the left I printed what would be their chassis if I ordered one. Right is what I came up with.


The Narrow Garage wheels have 17 tooth 0.2 MOD gears, but those bright silver wheels are a turn off. So I will re-do the whole chassis using Kato SD40-2 wheelsets (blackened wheels). The Kato gears have 20 teeth. The motor would be offset to the side of the lay shaft.


And here the whole thing fits under the body.

The worm gear used on the layshaft has 12 teeth so the thing would have a 240:1 gear ratio. Might end up being loud, but it will be slow 

[Chris333]

@mmagliaro  Max looking at your Rocket photos. Did you use two 20 tooth gears? So 400:1 gear ratio?   

[mmagliaro]

@mmagliaro  Max looking at your Rocket photos. Did you use two 20 tooth gears? So 400:1 gear ratio?   

Yes, that is exactly what I did.  Two mod 0.2 20-tooth reductions.

[Jim Starbuck]

Outstanding work Chris!
What are the motor dimensions?

[Chris333]

It is about 10x13x8 standard Kato size.  I ordered the square motor Max suggested and if they show up from China I will try them. You can see the motor in the right window I have more space to go bigger.

I'll be doing DC so will need all the reduction I can get.

[Jim Starbuck]

Thanks Chris,
I’ve got a couple of those Chinese motors coming as well.

[u18b]

Really looking forward to seeing this progress.

[mmagliaro]

The only tricky think about the Minebea motor is that it has a very short 0.7mm (I think) shaft. So you will have to sleeve it up.  I like to use stainless steel capillary tube (you can search for that on the internet), because it is very strong and can be had with almost any ID and OD you need.  I have accumulated it in 0.7, 0.8, 0.9, and 1.0mm ID with 1.5mm OD so I can sleeve almost anything up to the "standard" 1.5mm.  It also allows you to extend the motor shaft with something rigid enough to support a worm.

Edit... per Peteski's correction further down, it has a 1mm diameter shaft and it is about 1/4" (or around 6mm) long.

[peteski]

The only tricky think about the Minebea motor is that it has a very short 0.7mm (I think) shaft.  So you will have to sleeve it up.  I like to use stainless steel capillary tube (you can search for that on the internet), because it is very strong and can be had with almost any ID and OD you need.  I have accumulated it in 0.7, 0.8, 0.9, and 1.0mm ID with 1.5mm OD so I can sleeve almost anything up to the "standard" 1.5mm.  It also allows you to extend the motor shaft with something rigid enough to support a worm.

My Minebas (part# SS10G0RTME) has a 6mm long 1mm diameter shaft.

[nkalanaga]

If the "bright silver" wheels are made of typical model railroad metal, you should be able to blacken them fairly easily, and save the cost of Kato wheels.

[peteski]

If the "bright silver" wheels are made of typical model railroad metal, you should be able to blacken them fairly easily, and save the cost of Kato wheels.

Exactly.  Or just paint the wheel faces grimy/rusty color. Those wheels seem to have low-profile flanges, and nice shiny metal treads.

[mmagliaro]

My Minebas (part# SS10G0RTME) has a 6mm long 1mm diameter shaft.

You are correct, Peteski.... everybody FORGET what I said.  I was confusing this with the super short shafts on the little motors I've been working on for the Rocket.  Yes, the Minebea has a 1mm shaft and it has a good length on it.  In fact, it was long enough that I was able to modify it by pushing it through the armature and out the back to make a dual-shaft motor (not easy to do, I warn you).

[Chris333]

Sorry I don't want shiny treads. I really dislike those wheels. Kato wheels are already in the mail. Just need to make a few tweaks to my chassis to fit those wheels.

Have a bunch of Kato wheels, but their gear is offset to the side and I doubt they are 0.2 mod.

Toma Model Works makes the same type of wheelsets with 0.2 gears and blacked wheels, but he doesn't list them separately.

[peteski]

Sorry I don't want shiny treads. I really dislike those wheels.

Ah, so you dislike even the threads.  So using the blackening solution nkalanga mentioned was not an option either?

[Chris333]

I'm never gonna be able to blacken like a Kato wheel.