944 Class 4mm Chassis

How to do it, advice sought and offered.
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David Elvy
Posts: 452
Joined: Tue Aug 21, 2012 6:26 am

944 Class 4mm Chassis

Post by David Elvy »

I purchased the chassis shown in the accompanying photo a few years ago from I think Caley Coaches to use under a DJH 944 Class body.

First problem is the etch is designed for a rear radial truck rather than a pony truck, second think to resolve is that the etch came with out any coupling rods, the DJH body dopes have a set of rods but unfortunately not knuckled.

Q1 has anyone used this chassis before and how did they accommodate the rear pony truck?
Q2 the chassis etch came minus any frame spacers, not being a 4mm modeller could someone with a bit more experience please suggest where and what frame stretches to fit?
Q3 does anyone know a source for a pair of suitable knuckled side rods?
Q4 any advice re a suitable motor and gear box would be appreciated, I was thinking of a high level gear box, suggestions/advice appreciated?
Q5 Campbell Cornwall's book states the frames were cranked to accommodate the swing of the rear pony truck, suggestions as to whether this is required, by how much and where to make the crank would be appreciated?

Any other advice from any one that may have previously built one of these models would be appreciated, thank you.

David
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jasp
Posts: 475
Joined: Mon Aug 20, 2012 5:40 pm

Re: 944 Class 4mm Chassis

Post by jasp »

David
The frames look like they are from Alan Gibson and are profiled, not etched.
Somewhere in the bowels (?) of my loft is a largely built 944 for which I made frames, unfindable in the near future.
My recollection is that I did narrow the frames for the pony truck, but can’t be sure.
Currently, one of my to-dos is 944 frames and side rods. The frames will be scribed on nickel silver sheet and the rods, hopefully, 3D printed, probably by Shapeways, unless I can find an alternative.
Time scale .....? Currently working slowly on the above for 439 class so I have no idea how soon I will get to the 944
Frame spacers, will depend on frame thickness and track gauge.
I am aware of one other who is going to build a 944, in P4 so he also might be interested in frames and rods
Hope this info helps
Jim P
lindsay_g
Posts: 397
Joined: Mon Aug 13, 2012 8:43 pm

Re: 944 Class 4mm Chassis

Post by lindsay_g »

It indeed looks like an Alan Gibson milled chassis - the part is still available in their catalogue. From the same source you'd be able to obtain frame spacers (whether 00, EM or P4). Suitable wheels will probably be available from the same source. These chassis are designed to be used with hornblocks available again from Alan Gibson or the likes of High Level especially the latter's Spacesaver hornblocks if it is to be modelled in 00. Alternatively you might want to use some blanking etch along with suitable bearing inserts if it is to be modelled with a rigid chassis giving you more room to play with between the frames. Whatever route you go down, the space available needs to be considered when choosing a gearbox.

High Level will in all probability have a gearbox to suit and for this you should use their planning guide, both for a gearbox of suitable width and drive arrangement to fit presumably within the tank area of the 944 (a scale drawing of the 944 would be rather useful to consider jointly with the planning guide). A 14 series Mashima motor will probably be of suitable size but again best considered against a scale drawing. You'll need to choose the motor before the gearbox as you'll need to order the gearbox with the correct diameter of worm gear (2mm if used with a 14 series motor).

'Fraid I can't really help when it comes to all the drive rodding. There is a universal etch available for the drive rods from Alan Gibson again and that does have fluted parts on it but for the rest of the rodding I'm of no help.

Cheers,

Lindsay
David Elvy
Posts: 452
Joined: Tue Aug 21, 2012 6:26 am

Re: 944 Class 4mm Chassis

Post by David Elvy »

Jim, correct the frames are machined and not etched. Its the positioning of the frame spacers which I'd appreciate some advice regarding, a pivot plate over the centre of the leading bogie is obvious and something for the bogie to pivot from behind the rear driver will also be required but would folk recommend a vertical frame spacer between each of the driving wheels, taking account of the gear box, or would that be overkill.

Wheels came with the kit which I purchased David Franks back when he had his supply stand, David also helped with other chassis parts such as axle boxes etc hence hoping to fit knuckled coupling rods rather than the single piece rods which came with the kit.

Thanks for all the advice.

David
jasp
Posts: 475
Joined: Mon Aug 20, 2012 5:40 pm

Re: 944 Class 4mm Chassis

Post by jasp »

Dave
Not usually necessary to have a lot of spacers, particularly given the thickness of the frames.
If you use the, downloadable, High Level motor and gearbox sheets, that should help establish their positions, after which you can look at main spacer positions. Others will depend on how you arrange bogie and pony.
Bring to the Dechmont weekend and someone will further advise
Jim P
Dave John
Posts: 204
Joined: Wed Aug 15, 2012 7:42 am

Re: 944 Class 4mm Chassis

Post by Dave John »

I used the Gibson frames as well. In EM I had to curve the frames in at both the front and rear. I just cheated and made a swing arm truck for the back. I'll post some pics when I take it apart for servicing.

I seem to remember having a serious hassle getting it to go round corners.
Mike 1
Posts: 49
Joined: Tue Feb 12, 2019 8:46 pm

Re: 944 Class 4mm Chassis

Post by Mike 1 »

Don't know how thick the model rods are, but if they are still available could you buy a second set and cut and shut to make the joint?

Mike
David Elvy
Posts: 452
Joined: Tue Aug 21, 2012 6:26 am

Re: 944 Class 4mm Chassis

Post by David Elvy »

In the coming months there will be a new etch available with the correct pattern coupling rods.

David
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