Bandai B Shorty Chassis 3

[wcfn100]

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 .

If I had the time I think it would still fit in the oem chassis and work .

Soooo the chassis can be cut and stretched 3 scale feet to give the correct wheel base .

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

Thanks Richie, but 2mm is only ~13".  I'm going to need at least 5mm.

I have a chassis started, I'll try and get some pictures later showing what's all going on.


Jason

[up1950s]

Thanks Ritchie, but 2mm is only ~13".  I'm going to need at least 5mm
----- Original Message -----
From: "TheRailwire" <admin@precision7.com>
To: <vale@nyc.rr.com>
Sent: Thursday, November 08, 2018 1:23 PM
Subject: New Personal Message: N:3' = 5.76mm


> You have just been sent a personal message by SandyEggoJake on TheRailwire.
>
> IMPORTANT: Remember, this is just a notification. Please do not reply to this email.
>
> The message they sent you was:
>
> Quote
>
> "That's about 2mm longer which is about 3 N scale feet ."
>
>Unless I'm wrong, 2mm in N scale is just 12.6 inches.  Not 3 feet.   So it seems a bit short, of the ideal still, no?  N:3' = 5.76mm
>
> BTW, can you provide a length and OD for the Bandai unit 3 worm, as well as describe the mesh plane (is the worm and worm gear both flat or convex; aka "non-throated" or is it machined around the circumference of either)
>
> While at it, what is the OD of the shaft?   
> Cheers.
> Jake
>
> Reply to this Personal Message here:

Ok , first sorry .

Not sure about the gear facing as asked but here is a shot of it , hope that helps .

The shaft is 0.97 OD mm x 30.44 mm long .

The worm is 4.35 mm OD (top of lands) 2.9 mm OD ( bot of grooves ) and 5.04 mm long.

As you can see the hole in the worm is differen to either end . the big hole is deeper I think ( I will measure it if asked ).

OEM the shaft free slides in the big hole and then is pressed fit in the small hole .

So this will still work as the worm can be reversed by carefully and squarely pressing the small hole in the shaft first , but not all the way . Thus giving you a bigger wingspan to the worms .

I remeasured the OEM end of worm to end of worm and got 32.99 mm vs 32.96 on the other motor . basically the same .

This time I reversed the worms and then got a end of worm to end of worm of 38.41 mm.

So the difference is 5.45 which is pretty close to the 5.76 desired . Added to that the worm and gear mesh in the center of the worm but the gear could be fudged more than enough outward on the worm to the point of to far than wanted .

[wcfn100]

Thank Richie.  I was starting to lean towards offsetting the motor but then I'd need to extend one side.  I'll have to get a press and try and replicate what you have there.

Jason

[Chris333]

One of these small gear pullers should do that:
https://www.ebay.com/itm/Walkera-W010-Gear-Pinion-Puller-Remover-Tools-Set-For-RC-Motor-Pinion-Parts-ED/111954055561?epid=1969240888&hash=item1a10fb5189:g:FGYAAOSwcUBYQEVV:rk:4:pf:1&frcectupt=true

[wcfn100]

One of these small gear pullers should do that:
https://www.ebay.com/itm/Walkera-W010-Gear-Pinion-Puller-Remover-Tools-Set-For-RC-Motor-Pinion-Parts-ED/111954055561?epid=1969240888&hash=item1a10fb5189:g:FGYAAOSwcUBYQEVV:rk:4:pf:1&frcectupt=true

Ordered!

Oops, not so fast, says it could be here by January 3rd. 

edit: Okay, found another seller.  Hopefully within 10 days.  Thx Chris.

Jason

[wcfn100]

Got my gear puller today and the 1mm pin isn't long enough to pop the worm all the way off but does enough to show that just extending the gears as far apart on the shaft as possible won't work.

Jason

[narrowminded]

Got my gear puller today and the 1mm pin isn't long enough to pop the worm all the way off but does enough to show that just extending the gears as far apart on the shaft as possible won't work.

Jason

Back the puller screw off and insert a spacer pin that sits within the bore to keep it guided.   Will the thing work if it can be extended further? 

[SandyEggoJake]

Yes, thx Richie. 

You read my mind... given the worm seems to be without any throat (a straight calendar rather than a concave surface centered over worm gear), it does open the door some to fudging a bit more by moving back the point of mesh back from the motor as you suggest.  Just 0.15mm further from stock mesh point seems very doable on a 5mm long worm.  Of course, such assumes the stock is not already meshing at the extreme end of the worms...   

Your idea of flipping the worms (assuming the teeth are symmetric) is intriguing as your pictures also show it allows the development of space on the shaft for possible placement of a flywheel on each end, which should help even out some of the hitch Jason shows (though such might be a unit specific issue) - especially as the critter bounces over a yard full of frogs.   (Again, not familiar with this unit, but the little I've read about them, some have reported quality issues.)

Seems promising enough to develop a prototype adapter base to give it a test run, yes Jason?   



 

[160pennsy]

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

Jason

Yesterday, qty=2 of these power chassis finally arrived in my mailbox. After a quick unboxing & inspection they were placed on a loop of Kato Unitrack where I performed some test runs . Once a few laps had finished the herky-jerky running was apparent on both units as well as a slight wobble (like one of the wheels was out-of-round). Some 1/4 ounce A-Line stick on weights were temporarily added on top to see if it helped but the running issues still remained. After disassembly of one unit, rolling the truck assembly by hand across my workbench, I could see the one wheel with the traction tire had an irregular motion compared with the other 7 wheels. Looking from the end of the truck the wheel top is slightly canted in toward the truck frame. I have not tried to pry apart the truck assembly to investigate further but the geared axle end (that press fits into the traction tire wheel) might have gotten deformed or slightly bent during the manufacturing / assembly process. When I get a chance I'll try to post some photos...have other's seen the same anomaly?   

[wcfn100]

What I need is the worm from a Bachmann 40/70 tonner but I won't pay that much for just the gears.  Not sure if the pitch matches though.  I'm probably going to get one of the Tomix worms but need to know if they are 1mm or 1.5mm shafts. 


Jason

[Chris333]

Just one 44Tonner worm?

[wcfn100]

Just one 44Tonner worm?

2

Jason

[Chris333]

I was going to take a 44T motor and put it in a Skarloey HOn30 chassis. I'd only need one worm for that so I'd have a spare. But only need to do it once.

[SandyEggoJake]

Jason,

You can get the Bmann 44/70T motor and worms from their parts dept for about $22 bucks.

https://estore.bachmanntrains.com/index.php?main_page=product_info&cPath=70_679&products_id=9995&zenid=8s65ds7mapa4hqpbq95idl0ou7

Of course, about $10 bucks per is about the same price NWSL sells their superior steel worms.....

[CNR5529]

Trying to track down a version of the Bandai power chassis #3, 4 or 5, for my own steeplecab project, but none seem available. Are these chassis still being made? Where are you guys getting them from?

Thanks for the help!