Shortening plastic chassis

Have any questions or tips and advice on how to build those bits that don't come ready made.
craziej2k
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Shortening plastic chassis

Postby craziej2k » Mon Oct 05, 2020 8:17 am

Hi all! I'm in the process of fitting a Hornby pocket rocket 0-4-0 chassis to a 'Nellie' body I've got lying around but I need to shorten the chassis that the motor sits on. As this is my first time modding I don't really have a good idea on what to use to re-join the parts together afterwards. I originally thought maybe plastic cement but now I'm not so sure. Has anyone had any experience doing this sort of thing or has any advice on what glue to use?
Thanks in advance
- J

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GeraldH
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Re: Shortening plastic chassis

Postby GeraldH » Mon Oct 05, 2020 8:51 am

Your other option is to use the finer wheels, axles and coupling rods from the plastic chassis on the original metal chassis. I have done this three times on my two Nellies & my Triang diesel shunter with very good results. You do, however, have to add pickups on one side, as the new wheels are insulated on both sides. The old wheels were uninsulated on one side and picked up via the axles. I soldered pickups direct to the chassis on what was the uninsulated side. There are pictures of my adapted locos on my layout thread.
Gerald H - BNR Correspondent :)

My layout: http://www.newrailwaymodellers.co.uk/Fo ... hp?t=28854

Bigmet
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Re: Shortening plastic chassis

Postby Bigmet » Mon Oct 05, 2020 1:14 pm

craziej2k wrote:...Has anyone had any experience doing this sort of thing ...

Yes, and many times over. In the past twenty years have put well past a dozen different loco mechanisms into over 30 types of RTR and kitbuilt models never intended to receive them. Just completed stuffing a current Hornby 8F mechanism into the old H-D 8F body, to make a sufficiently heavy combination with current quality running and appearance.
craziej2k wrote:... any advice on what glue to use?

Don't bother! The plastic used in this moulding offers very poor bonding, world of trouble there.

I would suggest looking at different ways of proceeding.

Look at shortening the chassis by cutting off and discarding pieces from one or both ends to get it down to the required length.
Also consider stretching or modifying the loco body (which is moulded in polystyrene so cementing in new, and/or moving pieces about, is simple) to match the mechanism.
A combination of both is a possibility.

Attaching the mechanism to the body. This needs to be carefully thought out before cutting anything on either body or mechanism. It is potentially relatively simple to cement plasticard into the body, and to put small self tapping screws through the chassis moulding, and into the plasticard pieces cemented inside the body. But this needs to be planned for in advance so that there are no working parts in the way! Hint: these screws don't have to be on the length centreline. And if it really isn't possible to both get the mechanism to fit inside the body shell, and have them attached to each other in some way, even if that is by using blutack or similar, then you may just have to concede defeat and look for another body or mech..

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Bufferstop
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Re: Shortening plastic chassis

Postby Bufferstop » Mon Oct 05, 2020 3:04 pm

I go with GeraldH. Transferring wheels etc. to the original chassis will give you a better loco, the extra weight of the metal chassis makes a difference to pulling power. If you want something a bit different try a Nellie body on a Hornby Terrier chassis. An almost perfect fit.
nellie.jpg


[Edit] Oops! Wrong chassis, :oops: that one came from one of the H0 0-6-0s produced for Golden Valley Models.
Growing old, can't avoid it. Growing up, forget it!
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Bigmet
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Re: Shortening plastic chassis

Postby Bigmet » Mon Oct 05, 2020 7:07 pm

Bufferstop wrote:I go with GeraldH. Transferring wheels etc. to the original chassis will give you a better loco...

Yes, but crazie's opening post suggest he's only got the body. It's a different project if more parts have to be sourced.

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Mountain
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Re: Shortening plastic chassis

Postby Mountain » Mon Oct 05, 2020 8:47 pm

Before you start, have you considered retaining the Triang chassis and mounting the parts from the modern Hornby chassis onto them?
I have done this on one of my locos and I used a cable tie or two to hold the motor in place, and I had to custom make a double sided pickup assembly from a PCB board... And it giver a stronger chassis.

The wheelbases are the same. The axle width is slightly less with the modern parts, but not enough to cause any problems. If anything it makes a lovely free running chassis.

craziej2k
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Re: Shortening plastic chassis

Postby craziej2k » Mon Oct 05, 2020 9:51 pm

First of all thanks to everyone for all the help and advice, I really apreciate it. This afternoon I cut out some of the top of the chassis that was stopping the body from fitting on from both ends and it now sits on the chassis well. I'm gonna put some plasticard over the cylinders to stop the rods from falling out and build it up to give the body something more to sit on. The next step is to plan on where to connect the chassis and body.

The Nellie chassis is in rough shape and the engine was incomplete when I got it which is why I decided to swap the chassis. But I think i'll do the transfer idea next time as Xacto knives hurt!

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GeraldH
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Re: Shortening plastic chassis

Postby GeraldH » Mon Oct 05, 2020 9:57 pm

Bigmet wrote:
Bufferstop wrote:I go with GeraldH. Transferring wheels etc. to the original chassis will give you a better loco...

Yes, but crazie's opening post suggest he's only got the body. It's a different project if more parts have to be sourced.


Well spotted! :)

People have done this mod before. The newer plastic chassis is quite soft (polyethylene?) and too thick to cut with a sharp knife, but you could use a razor saw which will give you a slightly furry edge. There is probably is some kind of specialist glue that will work, but if you cut carefully you could probably get a fairly snug fit without having to glue anything on. In the one loco where I have adapted one of these chassis (BNR No 1) I drilled holes in the bottom of the chassis and attached it to the body using self-tapping screws. These screws fixed into mounting points within the body which were fabricated from a combination of Milliput and plastic card.
Gerald H - BNR Correspondent :)

My layout: http://www.newrailwaymodellers.co.uk/Fo ... hp?t=28854


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