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Split Chassis system and isolation of gearbox and motor


kandc_au
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Hi,

I have a spare body that I want to try a split chassis system on.
I can get my head around the concept and know I can get the jig and axles.

The issue I am having though is working out, how do I isolate the gearbox/motor so that it doesn't short?

 

Khris

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Ummmm ... can I ask why you should wish to do that? It seems to me reading other threads on here regarding split chassis, the consensus seems to be this is 'Not a Good Idea' (TM). I have some old split chassis stock that I bought years ago that seem to work at the moment, but I've been looking at ideas to replace the wheels on them with insulated ones instead - just curious.

 

Cheers,

 

Philip

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Assuming that you are using an axle with an insulated centre section for the gearbox.  You need to also insulate any chassis spacers as well.  I use double sided printed circuit board soldered on both sides (four solder fillets in total).  This helps stop the copper delaminating if subjected to an off centre thrust on the end of the chassis.  Create a gap in the PCB just inboard of the solder joints.  There have been a number of good articles in magazines over the years.  There was on by Barry Luck in the early days of MRJ that is worth seeking out.  I can't find my copies at the moment but perhaps someone better organised than me will tell you which copies it was.  Persevere, split axle chassis you make will be nothing like the proprietary ones.

 

Tony Comber

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3 hours ago, Philou said:

Ummmm ... can I ask why you should wish to do that? It seems to me reading other threads on here regarding split chassis, the consensus seems to be this is 'Not a Good Idea' (TM). I have some old split chassis stock that I bought years ago that seem to work at the moment, but I've been looking at ideas to replace the wheels on them with insulated ones instead - just curious.

 

Cheers,

 

Philip

I have read in the past that you can make very good ones, so I was thinking of having a go.
A member whom I have not seen post in a long while (Bertie Dog) was quite proficient I believe!
The commercial ones are another kettle of fish completely.

Khris

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1 hour ago, shipbadger said:

Assuming that you are using an axle with an insulated centre section for the gearbox.  You need to also insulate any chassis spacers as well.  I use double sided printed circuit board soldered on both sides (four solder fillets in total).  This helps stop the copper delaminating if subjected to an off centre thrust on the end of the chassis.  Create a gap in the PCB just inboard of the solder joints.  There have been a number of good articles in magazines over the years.  There was on by Barry Luck in the early days of MRJ that is worth seeking out.  I can't find my copies at the moment but perhaps someone better organised than me will tell you which copies it was.  Persevere, split axle chassis you make will be nothing like the proprietary ones.

 

Tony Comber

Thanks Tony,

I shall do some more research of MRJ. Must admit I didn't think to look there.
The thing that has me stumped is the fact that the gearbox would touch both sides of the split axle, the way I see it , thereby causing a short.
I am right , aren't I???

 

Khris

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4 hours ago, shipbadger said:

 There have been a number of good articles in magazines over the years.  There was on by Barry Luck in the early days of MRJ that is worth seeking out.  I can't find my copies at the moment but perhaps someone better organised than me will tell you which copies it was.  

 

Tony Comber

Barry Luck has an excellent website - as well as an equally excellent choice of prototype! I believe that almost all his locos are split frame although I could not quickly find a page on his site that addressed that particular aspect of loco building. 

You might want to sit down with a cup of tea before you dive into his website.

Best wishes 

Eric 

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Hi.

 

I know its not the same scale but have you looked at the work the members of the 2mm Scale Association http://www.2mm.org.uk/ ?

 

Split chassis design is pretty much the standard way members build engines. As a result there are many ways around dealing with split chassis design.

 

There are plenty of examples in the 2mm scale area here on RMWeb.

 

Missy.

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23 hours ago, shipbadger said:

Assuming that you are using an axle with an insulated centre section for the gearbox.  You need to also insulate any chassis spacers as well.  I use double sided printed circuit board soldered on both sides (four solder fillets in total).  This helps stop the copper delaminating if subjected to an off centre thrust on the end of the chassis.  Create a gap in the PCB just inboard of the solder joints.  There have been a number of good articles in magazines over the years.  There was on by Barry Luck in the early days of MRJ that is worth seeking out.  I can't find my copies at the moment but perhaps someone better organised than me will tell you which copies it was.  Persevere, split axle chassis you make will be nothing like the proprietary ones.

 

Tony Comber

Barry Luck talks about split chassis in MRJ No.19.

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The Branchlines split axles are biased to one side, so that it's possible to mount a narrow gearbox to the larger side. I put insulating tape on the inside of the frames where the gearbox goes. You also need to make sure that the motor is insulated from the frames.

 

 

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Morning!

 

As I'm now a complete convert to the benefits of split chassis, this topic caught my eye. 

 

As others have said, Branchlines make an excellent jig for producing axles from their components.  I use both the two- and three-part axles, using the three-part to keep the gearbox in a neutral section.  I wrote a couple of posts on this a few months ago on the Scalefour Society Forum.  You can see some being made here:

 

Making Branchlines split axles

 

I also adopt a belt and braces approach to making sure that the gearbox stays neutral by insulating the gearbox sides with cigarette paper held on with (soaked through by) superglue:

 

Insulating gearbox sides

 

And I use the same trick to insulate the body from the chassis, again to make sure that there is no chance of accidental contact.  Being (naturally!) only a fag-paper in thickness, this makes no visual difference.

 

52213058_Rizlainsulation1.JPG.b0013cdf284100b58f4b345d5a49c341.JPG

 

You just re-cut the hole for the motor/gearbox with a scalpel when all is set solid.

 

This is the locomotive is question - a Great Eastern Railway E22:

 

1499865618_E22finished(1).JPG.171e1c5b9f27c7e55741e797e959e5bf.JPG

 

I hope that all of these posts encourage you to have a go at split chassis.  The small amount of extra time invested up front is worthwhile compared to the alternative amount of fiddling that you have to do with *****ed pickups!

 

Cheers

Paul

 

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2 hours ago, Flymo749 said:

I hope that all of these posts encourage you to have a go at split chassis.  The small amount of extra time invested up front is worthwhile compared to the alternative amount of fiddling that you have to do with *****ed pickups!

 

Cheers

Paul

 

Hi Paul,
Thank you for the links.
What wheels do you use with the split axles please?

Khris

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12 hours ago, kandc_au said:

Hi Paul,
Thank you for the links.
What wheels do you use with the split axles please?

Khris

 

Hi Khris,

 

Usually it's Alan Gibson wheels.  That said, I've just used my first set of Ultrascales, and I think I'll be placing some orders to allow for the lead time of manufacture on the queue of unmade kits.

 

That said, the real question is probably about how you short them out to conduct the current from the tyre to the axle.

 

My preference is for the etched brass shorting strip.  Have a look at Brassmasters, although similar are available from the EMGS, and there used to be some in the Bill Bedford range.  They all basically do the same thing.  I use a square profile needle file to create a shallow recess on either side of the back of the tyre, then solder the strip in there.  Afterwards, they are filed smooth to ensure there is nothing that can catch in a flangeway.

 

I thought that I might have some photos of "here's some that I made earlier", but annoyingly I don't.  Must try harder with the next chassis.

 

I'm also experimenting with silver conductive paint, and it seems viable.  However it does take a few days to build up a properly conductive layer (measured by using a multimeter to assess resistance after each coat had dried).  It is a safer alternative than melting plastic spokes though!

 

Cheers

Paul

 

 

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