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Etched loco chassis


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EDIT: it's worth observing that the variations in the frames of GWR tenders is so great that trying to produce an etch to cover them all would be futile.

 

Chris

Ahh - the benefits og GWR Standardisation :scratchhead:

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  • 2 weeks later...

Here are images of the redesigned chassis for the Association Class 08/11 kits being test built, which will be included in the next batch of kits when they are released. A new 3D-printed set of outside frames is used, and the motor mounting simplifed.

 

The motor in the picture is a 99p 10mm square Chinese item as seen in another thread. Using this will probably be a bit optimistic, even if it fits inside the body it may well produce too much heat. More likely is an 10mm or 8mm coreless motor, mounted on a 3D-printed cradle.

 

Note: the 10mm square motor does fit inside the Farish 08 body and as that is lined with metal then for those going down that route it may well be a suitable choice.

 

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Edited by Chris Higgs
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The long march to build the new chassis continues. Here is the 64XX. I am pondering how to mount the motor here. Althought the new chassis do not include built-in cantilever gearboxes, there is a slot in the inner frames to solder one in. The photos highlight just what a gem of a moulding Bachmann have achieved here. My resolution to stick to the BR-era is sverely tested by their rendition of GWR green.

 

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And here is the 56XX. There is the option to drive off the rear or middle axles, and the slot which will take the 3D-printed radial truck is visible - you can also build the loco with a fixed trailing axle with extra sideplay.

 

Chris

 

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Perhaps the one most people are waiting for. The LNWR Coal Tank in the jig, after spacers added, and with the gears in. The radial truck is the same design as in the 56XX and provides the same options. Here I have built the alternative version of just having a fixed axle with extra sideplay.

 

The design has a two stage reduction with a motor sitting inside the boiler. It should also be easy enough to adapt to drive adirectly onto the rear axle.

 

Chris

 

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How is the extra sideplay achieved? It looks like the rear axle has the same amount of sideplay as the other three.

 

It looks to me as if the frames are less far apart there - hence the extra side play. It is obviously well disguised even from this angle.

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It looks to me as if the frames are less far apart there - hence the extra side play. It is obviously well disguised even from this angle.

 

The insides of the frames are the same width apart throughout. But they are only single thickness at the rear. So extra sideplay of 0.5mm there.

 

Chris

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Generally, 2mm models do not quite give that weight in the hand feel you get in the larger scales. There are however exceptions.

 

The second photo shows more clearly how the frame narrowing for the radial truck is achieved.

 

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Edited by Chris Higgs
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Probably last of the test builds for now is the G6. Due to space restrictions within the loco body, this one just drives directly off the rear axle, with an 8mm diameter motor somewhere close to where I have it perched in the photos.

 

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As a short reflection on building this batch of chassis, I must say I am very pleased with how the double thickness frames have worked out. Whereas with 0.25mm thick frames I feel the frame spacers are there to stop the whole chassis becoming distorted, once they are doubled to 0.5mm thick the frames are well able to look after themselves and the spacers are just there to keep them the correct distance apart. The result is less spacers are needed and it is easier to fit things like 'Simpson springs' inside.

 

The only downside is a bit more preparation work, and you must make sure the two layers of frames are nicely sweated together, otherwise they will not fit into the jig.

 

Chris 

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On another thread it has been noted that the latest chassis come without a built-in cantilever gearbox. This is because I found a refined way to do these. When I designed the Black 5 replacement chassis I found the original method would not work, as the  Bachmann body only has a 6mm width within it, so is not wide enough. I therefore designed a separate gearbox, which then proved to be actually easier to build than the integrated ones. So the new chassis have a slot where the gearbox can be added, it locates over the axle bearing. For anyone who doesn't want the gearbox, it saves them cutting it off the chassis. Here the 64XX chassis models the gearbox.

 

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Edited by Chris Higgs
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I like the doubled-up frames. As you say, it makes for a more robust assembly with fewer spacers.  As there's now all this extra room in the chassis, how about a cosmetic inside valve gear etch...

 

The way you've set out the G6 is interesting, it is quite a low-slung loco.  Rather a pretty one too.  Mine will be one that was shedded at Feltham (70B). 

 

Mark

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The way you've set out the G6 is interesting, it is quite a low-slung loco.  Rather a pretty one too.  Mine will be one that was shedded at Feltham (70B). 

 

Mark

 

I'm in for a G6 chassis as well although I have no idea how/where I would use it. Back in the '60s Bob Wills released a 4mm kit for the G6 and I thought then what an attractive class of locos that they were. The proportions seem to be 'just right' so when Nick Tilston released his kit I bought one and it has been sitting in the gloat box ever since.

Incidentally, I'm wondering which size of wheel would be appropriate. They have 4' 10" drivers so are we to use 9.5mm or 10mm?

 

David

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I'm in for a G6 chassis as well although I have no idea how/where I would use it. Back in the '60s Bob Wills released a 4mm kit for the G6 and I thought then what an attractive class of locos that they were. The proportions seem to be 'just right' so when Nick Tilston released his kit I bought one and it has been sitting in the gloat box ever since.

Incidentally, I'm wondering which size of wheel would be appropriate. They have 4' 10" drivers so are we to use 9.5mm or 10mm?

 

David

 

I'm going for 9mm, allowing for the slightly deeper than scale flanges. I don't have any justification for one but it was used very local to me, as was a C class.

 

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I'm in for a G6 chassis as well although I have no idea how/where I would use it. Back in the '60s Bob Wills released a 4mm kit for the G6 and I thought then what an attractive class of locos that they were. The proportions seem to be 'just right' so when Nick Tilston released his kit I bought one and it has been sitting in the gloat box ever since.

Incidentally, I'm wondering which size of wheel would be appropriate. They have 4' 10" drivers so are we to use 9.5mm or 10mm?

 

David

 

The design will take 10mm wheels and still clear the brakeblocks so it is up to you. My personal choice would be 9.5mm

 

Chris

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The design will take 10mm wheels and still clear the brakeblocks so it is up to you. My personal choice would be 9.5mm

 

Chris

 

I think that I would tend to agree, Chris. The size of the wheels is something which distinguishes the G6 from many other 0-6-0 tank locomotives. It may only be a matter of three to four inches but it is certainly noticeable.

 

David

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  • 2 weeks later...

By now I hope all who expressed an interest in the various chassis have received a reply from me.Most of the first batch were sold although the odd one is still available. I plan to put an announcement in the next newsletter to seek out those who don't do online, although timescales dictate these won't get produced before the autumn.

 

Chris

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By now I hope all who expressed an interest in the various chassis have received a reply from me.Most of the first batch were sold although the odd one is still available. I plan to put an announcement in the next newsletter to seek out those who don't do online, although timescales dictate these won't get produced before the autumn.

 

Chris

 

Chris, I did PM you about a 47xx chassis, but have not seen any reply.

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Hi Chris. I sent two emails. One for 2 x 64xx and another adding a G6. I didn't get any replies but I just assumed that you wouldn't reply to each individual message.

 

David

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By now I hope all who expressed an interest in the various chassis have received a reply from me.Most of the first batch were sold although the odd one is still available. I plan to put an announcement in the next newsletter to seek out those who don't do online, although timescales dictate these won't get produced before the autumn.

 

Chris

 

Hi Chris,

 

I mailed and PM'ed you about the G6 and O2 chassis, but have had no reply.  Did something get lost????

 

Many thanks,

Jon

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