Bandai B Shorty Chassis 3

[wcfn100]

Stemming from the PE Steeplecab thread, I ordered a Bandai Chassis 3.  Most of the powered chassis aren't usable for North American locomotives, even the small steeple cab types as the wheels are too small and the whell base and truck centers are too short.  But this one had some promise after looking at as many pictures as I could find (except for the truck centers).





As soon as I got it, I grabbed the calipers.

Wheel Diameter ~5.6mm -> 35 1/4"

Wheelbase ~ 14mm -> 7' 4"

Truck Centers ~ 28 mm -> 14' 8"

Using a drawing for a Westinghouse Class D locomotive like from the PE thread you can find these numbers.

Wheel Diameter = 38" (I have seen other Class Ds listed with 36" wheels).

Wheelbase = 7' 4"

Truck Centers = 17' 8"

The wheels match pretty close and the wheelbase is great, but the truck centers are off by 3' (which can easily be seen in the PE thread).  It doesn't look like the worm gears can be pushed out far enough, but I may give it a try.  Or maybe try those funky worms form the SW9 sound thread.


Jason

[narrowminded]

... but the truck centers are off by 3' (which can easily be seen in the PE thread).  It doesn't look like the worm gears can be pushed out far enough, but I may give it a try.  Or maybe try those funky worms form the SW9 sound thread.


Jason

If that was all that was stopping you I could probably make shaft extensions to move the worms.  If the worms could be moved, would you then cut and splice the chassis to move the trucks outward?

[wcfn100]

If that was all that was stopping you I could probably make shaft extensions to move the worms.  If the worms could be moved, would you then cut and splice the chassis to move the trucks outward?

The key at this point is how much space is available for the worm gear under the short hoods of a Class D if the trucks are on proper centers.   That's why those Tomix worms could well work here.

Jason

[narrowminded]

The key at this point is how much space is available for the worm gear under the short hoods of a Class D if the trucks are on proper centers.   That's why those Tomix worms could well work here.

Jason

I guess I'm not familiar enough with either of those parts to understand why one might have a chance where the other wouldn't.   I thought that you were just trying to move them outward and running out of shaft length, not something more/ other than that.

[wcfn100]

I guess I'm not familiar enough with either of those parts to understand why one might have a chance where the other wouldn't. 

Just the diameter of the worm gear.  The Tomix appears to be much smaller.

Jason

[narrowminded]

Just the diameter of the worm gear.  The Tomix appears to be much smaller.

Jason

Ah, yes.  So you have to lower the motor, too.  Well, if you get stuck with that adaption, same offer.  Adaption or worst case, even making the worm. 

As a side note, if these were mated to true enveloping worm gears or even just wide toothed modified spur gears (angled teeth) this could/ should not  be done.  The worm gear tooth angle changes based on the worm diameter and as such it requires the worm gear to be mated to a specific worm diameter as well as pitch.  If this worm gear face is fairly narrow, just misaligning to accomplish the truck pivot as some of the smaller locos do, you can get away with it.  The teeth are more like pins instead of teeth, found to be sufficiently strong for the light service, and with a sloppy fit can be misaligned a fair amount.    But if the teeth are fairly wide and use a universal joint drive shaft as so many do, not misaligning the gear to accomplish pivot and with the teeth cut at an angle to mate to the worm, this may not be such a good idea because of that angle. 

Probably too much information but thought I'd add it for those not used to gear applications but maybe interested in a more thorough understanding of the gears we encounter. 

[SandyEggoJake]

Jason, could you use the specs off a tomytech worm?  I have a TM-07 in front of me.

By the way, I know next to nothing about these Shorty chassis 3 but recently started to research them after learning it was a better puller than its predecessors from Kato, the 11-105, 11-106 & 11-107. 
Though perhaps the difference is just more tractive effort from added weight?   (I read elsewhere these Kato products had 5.1mm (N:33") wheel but see you report the Bandai 3 is 5.6mm?  So maybe the larger wheel OD helps too, though that seems to counter my understanding of the relationship between pull and wheels)

Regardless, I'll be interested in photos from your disassembly of this chassis.

In particular, I'm now wondering if the smaller Kato wheel can be swapped in to this chassis (and if it would still operate).   As it seems you are OK with the 5.6mm wheels, this might not be an issue for you.  But learning the degrees of freedom on wheel swaps would allow you to consider something larger / closer to 38"... namely the 40" /64 you can find at NWSL pg 3-24 here.  http://www.nwsl.com/nwsl-online-catalog.html


And while this is not your first rodeo, and while his is not a BanDai chassis, if you've not seen it, you still might wish review @randgust adapter resin base for the TomyTech chassis to create a wider truck center base.  (http://www.randgust.com/prod04.htm)  The instructions that come with his item provide an excellent detail on how to extend the shaft. 

Cheers,
Jake

[wcfn100]

By the way, I know next to nothing about these Shorty chassis 3 but recently started to research them after learning it was a better puller than its predecessors from Kato, the 11-105, 11-106 & 11-107. 
Though perhaps the difference is just more tractive effort from added weight?   (I read elsewhere these Kato products had 5.1mm (N:33") wheel but see you report the Bandai 3 is 5.6mm?  So maybe the larger wheel OD helps too, though that seems to counter my understanding of the relationship between pull and wheels)

The wheels are definitely 5.6mm, but in checking again, I see that one wheel on one truck has a traction tire. 

And while this is not your first rodeo, and while his is not a BanDai chassis, if you've not seen it, you still might wish review @randgust adapter resin base for the TomyTech chassis to create a wider truck center base.  (http://www.randgust.com/prod04.htm)  The instructions that come with his item provide an excellent detail on how to extend the shaft. 

That's what I'm looking at doing.  First I'll mock it up in styrene and see if the current worm gears can be used.  If not, maybe try the Tomix where I'd have drop the motor down a bit and then draw it up in 3D.

Jason

[Chris333]

Have you ran the chassis? It might not matter what the wheel base is on a rocket.

[wcfn100]

Have you ran the chassis? It might not matter what the wheel base is on a rocket.

I did test it and thought it had a decent low end.  Maybe with a wider wheel base truck the gearing is a little better than some others. 

Jason

[Chris333]

I never had one, just figured...

[wcfn100]

I little herky-jerky but I think that will smooth out with some weight.

Jason

[SandyEggoJake]

Hmmm,  that does have a bit of a hitch.  Is it lubed up?  Does it have a flywheel? 

For full disclosure, I really don't know what the OD is on the older Kato versions was... I base the Kato = 5.1mm on what is listed here: http://www.trainweb.org/tomix/chassis_dim.htm

Also, while pestering you, are you familiar with the Unit 5 version?  Wheel dimensions seem same, and main difference is the lack of the side "claws".  But what do I know... 

Unit 5: https://www.1999.co.jp/eng/image/10295025/20/2
Unit 3: https://www.1999.co.jp/eng/image/10159615/20/3 

[wcfn100]

Hmmm  that does have a bit of a hitch.  Is it lubed up?  Does it have a flywheel? 

Also, while pestering you, are you familiar with the Unit 5 version?  Wheel dimensions seem same, and main difference is the lack of the side "claws".  But what do I know... 

Unit 5: https://www.1999.co.jp/eng/image/10295025/20/2
Unit 3: https://www.1999.co.jp/eng/image/10159615/20/3

Don't remember why I picked the 3.  I think it's all the same for our purposes.

Jason

[up1950s]

I have one of those Bandai 3's , I just popped the hood .

End of worm to end of worm , both with the shaft flush measured 32.96mm .

I then removed the worms and put then back on just enough so I couldn't remove them by hand and outside worm to outside worm was 34.95 mm . ( I would glue or something on a final assembly )

That's about 2mm longer which is about 3 N scale feet .SEE PAGE 2 for error correction please

If I had the time I think it would still fit in the oem chassis and work .IT STILL WILL , SEE PAGE 2

Soooo the chassis can be cut and stretched 3 scale feet to give the correct wheel base . IT STILL WILL , SEE PAGE 2

The contacts , motor cover fit , and the entire assembly fitting in the steeple cab is still unknown .