MTK class 59 kit - Let the challenge commence.

Terry Bendall
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Re: MTK class 59 kit - Let the challenge commence.

Postby Terry Bendall » Thu Apr 15, 2021 7:45 am

Terry wrote:As you can see this is the void I'm having work out how to fill...


That is certainly a bit of a challenge. :) Given the thickness of the sides of the body fitting a modern RTR chassis would not be easy. An old Lima chassis might be a starting point but the vertical sides, which add strength would have to be removed and replacements provided. I would be inclined to go for a flat piece of brass with cut outs for the bogies and some angle section soldered to the inside of the body with holes drilled and tapped for fixing screws but that is my metalworking background coming in. :) Using metal would allow for mounting points for the bogies to be created. Not that easy but the whole project is a challenge anyway. :)

Terry Bendall

Terry

Re: MTK class 59 kit - Let the challenge commence.

Postby Terry » Thu Apr 15, 2021 8:51 am

Terry Bendall wrote:
Terry wrote:As you can see this is the void I'm having work out how to fill...


I would be inclined to go for a flat piece of brass with cut outs for the bogies and some angle section soldered to the inside of the body with holes drilled and tapped for fixing screws but that is my metalworking background coming in. :) Using metal would allow for mounting points for the bogies to be created.

Terry Bendall


That is where my thinking was beginning to go also Terry, so its very heartening to have that view from someone more experienced. I'll need to decide on that sort of solution before going much further with the body in order to get the soldering out of the way. My metalworking experience is limited. What sort of thickness of brass plate would you envisage? I was thinking maybe 1mm or would I need to go thicker? Weight is already a challenge in that the springing solution needs to be able to handle that. The white metal body shell is approaching 350 gms, motor, bogies and other bits will add to that.

Thanks

Terry

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ianpenberth
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Re: MTK class 59 kit - Let the challenge commence.

Postby ianpenberth » Thu Apr 15, 2021 9:14 am

The sprung weight of the Bachmann 66 is a shade over 500g. Those alloy lumps inside modern diesel models are unbelievably heavy...
Ian
PenBits Model Railways - Diesel bogie springing and detailing

Terry

Re: MTK class 59 kit - Let the challenge commence.

Postby Terry » Thu Apr 15, 2021 3:14 pm

ianpenberth wrote:The sprung weight of the Bachmann 66 is a shade over 500g. Those alloy lumps inside modern diesel models are unbelievably heavy...


Well that comes as a bit of a relief Ian! I'll still confirm the full weight when I've worked out everything, but it sounds like stronger springs may not be needed. That does of course depend on what sort of Heath Robinson subframe arrangement I come up with!

Thanks

Terry

bécasse
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Re: MTK class 59 kit - Let the challenge commence.

Postby bécasse » Thu Apr 15, 2021 7:51 pm

Terry wrote:I'll need to decide on that sort of solution before going much further with the body in order to get the soldering out of the way. My metalworking experience is limited. What sort of thickness of brass plate would you envisage? I was thinking maybe 1mm or would I need to go thicker? Weight is already a challenge in that the springing solution needs to be able to handle that. The white metal body shell is approaching 350 gms, motor, bogies and other bits will add to that.


The thicker the brass plate the more difficult (impossible?) it is to solder it, as anyone who has worked in 7mm or larger scales will know. I wouldn't choose to use brass sheet thicker than 0,5 mm for frames. If you really think that you need to go thicker than that for strength, I would take a cue from baseboard construction and use a sandwich technique, with two "frames" each side separated by suitably located strips of brass, etch waste for example. It would need to be carefully thought out beforehand, particularly the location of the separator strips, but it would certainly be strong.

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Will L
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Re: MTK class 59 kit - Let the challenge commence.

Postby Will L » Thu Apr 15, 2021 8:30 pm

20 thou brass sheet (.5mm there abouts) would be more than strong enough to do the job, but as Bécasse says soldering big bits gets difficult to do with a soldering iron. 15 thou sheet will be fine as long as its properly designed. I doubt the Penbits bogies will be made of anything thicker than that.

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grovenor-2685
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Re: MTK class 59 kit - Let the challenge commence.

Postby grovenor-2685 » Thu Apr 15, 2021 8:37 pm

Essentially the inner chassis will have to replicate many features of the Bachmann cast frame in order to correctly accept the bogies and provide suitable mounting for the motor, so will inevitably be fairly complex, a horizontal sheet is not going to hack it.
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Keith
Grovenor Sidings

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ianpenberth
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Re: MTK class 59 kit - Let the challenge commence.

Postby ianpenberth » Fri May 07, 2021 8:47 pm

In fact, the Class 66 bogies would just require a flat plate, for the bolster tops to bolt up against, with 3mm holes at the pivot centres. With a 40thou plastic spacer between the bolster top and the plate, the worm shaft centre of the Bachmann drive unit would be about 6mm below the plate. Perhaps the motor could be slung below the plate? The 6mm distance could of course be increased by using thicker spacers, or joggling the plate.

I can confirm that the bogies are all 15thou brass and I've successfully used the same material for making up full chassis frames, stiffening either with perpendicular flanges or multiple laminations.
Ian
PenBits Model Railways - Diesel bogie springing and detailing

Terry

Re: MTK class 59 kit - Let the challenge commence.

Postby Terry » Sat May 08, 2021 1:34 pm

ianpenberth wrote:In fact, the Class 66 bogies would just require a flat plate, for the bolster tops to bolt up against, with 3mm holes at the pivot centres. With a 40thou plastic spacer between the bolster top and the plate, the worm shaft centre of the Bachmann drive unit would be about 6mm below the plate. Perhaps the motor could be slung below the plate? The 6mm distance could of course be increased by using thicker spacers, or joggling the plate.

I can confirm that the bogies are all 15thou brass and I've successfully used the same material for making up full chassis frames, stiffening either with perpendicular flanges or multiple laminations.


Thanks for that Ian, very helpful, and it gives me some further ideas on sorting the internals. I almost acquired a damaged Bachmann 66 (body damaged and motor issues) on ebay which would have been perfect, as I already have a new motor, but got pipped at the post. I hoped I could get it cheaper than getting the appropriate bogie parts from Bachmann direct. That last option is now likely what I will do having got a detailed component and price list of the bits needed.

The main area I'm trying to solution at present is how to fix the various internals, to the body sides but I'll wait until I have the chassis and internals all hanging together, then do some measuring and concoct a way to secure all that to some brackets fabricated to the inside of the body sides.

Meanwhile other projects are distracting me a bit, including reengineering an old part built Kemilway chassis for the Airfix Mogul, from OO to P4, mostly to try out my new Antex soldering station, and also to get some practice at making up an etched chassis. I suppose the collective audience here might finally conclude I am mad!

FYI, the Mogul chassis so far now with P4 frames and much fettled (to fit) cylinder frames. I was delighted when I pushed it along the work bench and it all worked without tight spots, although I suspect testing it on some track might prove a better test.

ImageIMG20210506162414 by terry.howlett, on Flickr

More on the 59 soon.

Terry Bendall
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Re: MTK class 59 kit - Let the challenge commence.

Postby Terry Bendall » Sun May 09, 2021 9:05 am

Terry wrote: I suppose the collective audience here might finally conclude I am mad!


Rule No. 1 Its your train set. :D

What other people think is up to them. Have fun, enjoy yourself and learn. :)

Terry Bendall


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