Best Of The TP56/TP70 Kitbash thread N scale

[u18b]

EDIT:  if you are new to this thread and don't want to wade through almost 50 pages, go to page 36 to see some models.
Pages 1-20 are a lot of discussion and development.
About page 20 is building.



This thread is dedicated to pooling ideas to make a pretty cool locomotive.

The TP56 is a switcher locomotive engine and body mounted directly onto an SD40-2 truck.
made by a company in Canada.

This just begs to be modelled.




The perfect starting truck appears to be the truck from a Kato SD40-2 mid version

Not the Snoot and not the early version.

The mid version has the worm built into the truck and has a finer worm to make it slower.
edited
You can see the part number on the truck.

Currently comes in:
black- Kato part # 929341
silver- Kato part # 929343
and BNSF green- Kato part # 929347




I think a good possible chassis in the Kato B unit driving chassis.
11-105,  106 or 107.  (the only difference is the sideframes- which we don't care about).
There may be something better out there. But this is what I'm going to try first.




Here is the chassis disassembled.  (photo borrowed from the net)
What makes this a good choice, I think, is the size of the motor.  Admittedly fast, but the size is great.

Also, look at the u-joint shaft and worm u-joint cup.



Shazzam!   They are identical to the parts in the SD40-2 truck.
In this shot....
Right- SD40-2 shaft
Middle- B unit chassis shaft
Left- B unit cup




So here is a side-on shot of the Kato HT-C truck.



Now, we have two possibilities for mounting this motor.  I'm cutting and pasting trying to keep everything to scale (what I call, virtual kitbashing).

First, lets try putting the motor in the front.
This way has the worm placed directly on the motor.   The motor shaft MIGHT be too short.  And some material from the worm cover might need to be removed to get the motor close.

As you can see it sticks out a little too much.



And here is a shot of the Kato worm cover removed.  The front of the truck is to the left in this shot.




Here is the front of the truck.   This might not work because maybe you can't remove material from the cover because that spot holds the worm bearing.




So let's try the other end.  This is my first choice.  Room seems to be better.
Disadvantage is that we have to couple the shafts somehow.

One possibility might be to trim the Kato SD40-2 cup and use it like a joiner to join the shafts.

Another possibility might be to cut and splice the B unit grey shaft and make it VERY short.
If that works, a Shapeways part might work.




Another possibility would be to use some K&S brass tubing as a kind of u-joint.  This small tubing just presses into the cup.



Which way will work?

Won't know till I get a chance to try it.

But this should start us up with possibilities.

[u18b]

-moved from other thread-

I've already been collecting as many photos as I can find for research/modelling purposes.

Here is my album so far.

https://goo.gl/photos/WJgRsQCCg2PmeBS48

[randgust]

If you can still find one - the Bachmann GE 44-tonner / 70-tonner motor is a double-shafted version of the Kato 11-105 motor (12v) with a worm already on it.  If nothing else, the shaft is a lot longer than the stock Kato.

Last time I looked it was off the website, I got one to play with a long time ago.

[u18b]

If you can still find one - the Bachmann GE 44-tonner / 70-tonner motor is a double-shafted version of the Kato 11-105 motor (12v) with a worm already on it.  If nothing else, the shaft is a lot longer than the stock Kato.

Last time I looked it was off the website, I got one to play with a long time ago.

True.  The longer shaft might work better.

But they are not the same.

I got my 44 tonner out.  The motor is about 15 mm long.

The B unit chassis motor is only 11 mm - about 1/3 shorter.

[u18b]

Oh.
One other info I forgot.
Not sure if it will matter, but....

Typical Kato/Atlas motor/worm shaft diameters is 1.5 mm.

The shafts on both the SD40-2 mid version truck worm and the B unit motor is 1 mm.

 

[u18b]

Randy,

In the other thread..... you said:

Now, these motors at the page top are the EXACT SAME CASE as the Kato 11-105 critter motor.   I buy them just for the gearhead and toss the 3.5v motor.
http://www.gizmoszone.com/shopping/agora.cgi?product=Gearmotor;ppinc=1g

Going to that website, which motor do you usually buy?

[narrowminded]

It looks like that motor shaft could be fitted directly to the worm.  If it takes resizing or sleeving the worm, I know a guy.

[mmagliaro]

How much room do you have for the motor?  Because if you can manage a 10mm x 12mm x 15mm long,
I strongly suggest you consider the Mashima 1015, rather than any of the critter or other little motors on Gizmoszone.  They are not very robust motors, and the Mashima will far outpower them.
(Gizmoszone even sells the Mashima for about $35).

[nscaler711]

Like I said in another thread, if you make multiples, I want one!! 

I will be watching this thread like crazy.

[Missaberoad]

I have a junk mid pro SD40-2... Watching this with great interest 

[dcutting]

PM me and we can work out the CAD for the shell... I've already got the basic shapers toughed out and it just needs doors. Might also be able to help on mechanism.

[randgust]

I buy the Part No.: GH810514V3 8mm x 10mm(Dia.) one with the 5.14:1 reduction.  It comes with a 3v motor.   

You'll want to mark the motor "3V" because once you unscrew it from the gearhead you can't tell it apart from the Kato other than the notched "D" end shaft you have to replicate on the 12V Kato.   I just use an abrasive disk to cut a hair off the Kato shaft and grind it to the "D" shape to fit the Gizmoszone pinion.

If you have DCC you can probably leave the 3V on there if you can control it OK through a speed table.  Just don't kid yourself and think you can make these work right with a dropping resistor off of DC.   Not that I haven't tried - the tiny ones work OK but these motors are really too big and the resistor overheats under load.

I think they do the same gearhead now with a metal shaft...can't find it though.

I did buy one of those Mashimas and attempt a tender drive project.  As much as it should have been a superior idea, I got better speed control and torque and a much quieter result out of the Kato 11-105 motor plus the Gizmoszone gearhead.  That's what's in my Lima 2-6-0 and the Mashima motor is back in the parts box.   It's well made for sure but if you've got room for the gearhead on a Kato you might be surprised.   Without the gearhead, no comparison though, the Mashima is a 'real' motor.

We'll see how this goes but my idea at the moment is to rebore the old Roco worm and end bearing to accept the shaft right off of the gearhead.  I suspect that's the same bearing they always used and I have a ton of those.

Cutting Edge models does have the HT-C sideframes on Shapeways.   I could kick myself because I had a brass set of Precision Scale ones for years and finally sold them, apparently, in my ongoing efforts to get rid of some of the weird stuff I've collected with no project in sight.  Memo to self, bad idea.

[dcutting]

Why use the Kato gearbox? I imagine that it would be much easier to 3D print a gearbox and populate it with the kato gears. Then you could have the tower shifted back, giving you enough room for a full atlas motor. Lemme take a look at what I was looking at for this when i tried to do it the first time around...

[randgust]

I'm getting your sideframes printed in that flexible black plastic and appear to be #1.   If that stuff can take a little more of a beating than fragile FUD and have the tolerances, agreed.  But Kato designs some of the tiniest pins and clips of anybody that have to be replicated.

I'm still not a big fan of RP printing of anything that's supposed to have smooth steel surfaces on it, particularly steam boilers and diesel hoods.  If there's no detail to be lost you can sand, prime, fill, but if there is detail, well you either end up with the layer lines or sand the detail off.  I've seen far better resolution off of non-Shapeways prints, so I know it can be done, just sorta waiting it out.  Meanwhile I'll probably work in styrene and brass.

You're running into the same issues, however, that I do when I'm looking at a kit concept.  First, where do you get parts from?  If you can't get a steady supply of Kato HT-C trucks (now all out of stock) you're kind of messed up.   Kato is kind of notorious for that - trucks are the first thing to go out of stock on a locomotive, maybe from DCC meltdowns, I don't know.   The only reason my Climax and Whitcomb kits have been a success is because Kato has now been steadily supplying the 11-105 chassis for over TEN YEARS, and Tomytec has done the same with their chassis, and both of them the parts are essentially dirt cheap.    Showcase did a fantastic job on their bitty Shay, but add their body with the Searails power truck and you're into $300.

Same thing with Atlas - the CF7 only works as long as Atlas makes Phase I GP7's and does the long hood.  But that one is actually a bit of a partnership and I've worked with them on making sure extra hoods are part of the China production orders.   I'm not recasting or reproducing their parts in any way.

There's always a tradeoff between what you can do as a modeler yourself and what you can expect other people to do as a kit, too.   Probably 25% of my kits get some custom build involved on mechanism, handrails, or painting - which is OK.    I've looked at several projects and had to decide somewhat reluctantly that it just wasn't feasible to invest several thousand in kit production (mostly brass etchings), but I'd still do one myself as a one-off.   That can change - I found a way to make a reproduceable 25-tonner using a Shapeways shell - but it's too difficult for most people to build even with an RTR shell and and RTR mechanism so I've only done a handful.

[dcutting]

Randy,

I'm starting to move towards sculpteo for my smaller models. They have the new CLIP printers from Carbon3D and you can hardly see the layers... see this page... http://www.cescalemodels.com/n-searchlight-signal-assembly. I can replicate the Kato truck no problem... but I guess the problem is that you still need the gears, trucks, etc.

Here's the render of the CAD model that I've done... it's got a NWSL motor in it (12V) and would work with the Kato truck:

So I think the issue at this point are the gears, axles, wheels, and pickups... maybe I could invest some $$$ into an injection mold for a small kit of delrin gears that could be used on a variety of small units like this. The wheels and worm could be managed with some kind of CNC lathe equipped supplier. For the pickups, you could do either small PB wires or make a small aluminium stamp to form PB etchings into the correct shaped points. I could then just snap on my Kato sideframes from shapeways. The big thing is the injection mold. That will be a challenge as I don't have any contacts for IM of that size and material, plus I'll need some capital to invest in the tool. The gears can be prototyped in 3D printed plastic for now.

David