Converting Tender Chassis

J Gleeson

Converting Tender Chassis

Postby J Gleeson » Sat Jul 21, 2018 8:56 am

I have a DJH LNER 8-Wheel Tender. This has an inside bearing chassis; the tender frames simply sit on this. Has any member converted one of these tenders to P4, and if so, how.
I would like some ideas on springing/compensating this chassis to give an economical P4 conversion-it seems wasteful to just junk it.
I look foward to members ideas on this.

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PeteT
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Re: Converting Tender Chassis

Postby PeteT » Sat Jul 21, 2018 9:41 am

I'd start by looking at the Brassmasters tender chassis supplied with their A3 and A4 easi-chas conversions - there are quite a few photos on the website.

I don't know whether the tender chassis would be available separately - Brassmasters are very good at selling individual etched sheets, but it depends what else that sheet might cover - but it gives an idea as to how to organise a simple CSB tender chassis.

Cheers,

Alan Turner
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Re: Converting Tender Chassis

Postby Alan Turner » Sat Jul 21, 2018 11:22 am

Lanarkshire models do an 8 wheel tender CSB chassis - however it's for a WD..

http://www.lanarkshiremodels.com/lanark ... te_169.htm

regards

Alan

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jon price
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Re: Converting Tender Chassis

Postby jon price » Sat Jul 21, 2018 1:40 pm

Looking at my DJH Claughton, which I am assuming may be similar, the easiest approach would be to make the rear axle fixed, put a knife edge bearing down the centreline above the other three, open up the top of the slot above them, and raise the keeper plate with a thin washer on each of the bolts. Unless your track is like the Pyrenees the increase in the slot, and the washer combined need only be a millimeter altogether. You would then have a rigid axle, and three compensated. You could even easily retrofit this if the axle retaining box structure is already made.
Connah's Quay Workshop threads: viewforum.php?f=125

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zebedeesknees
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Re: Converting Tender Chassis

Postby zebedeesknees » Sat Jul 21, 2018 2:25 pm

The Lanarkshire tender chassis has a slightly different axle spacing; between 1st and 2nd and 3rd and 4th are the same as the A3/4 tenders, but the 2nd - 3rd spacing is 1mm less on the WD tender. Get-away-with-able...

The Brassmasters Easi-chas conversion looks like a better bet if you don't want to go the whole hog and buy a Finney tender, also available from Brassmasters. With a s/h Hornby tender and easi-chas, less work..

I have built a couple of Lanarkshire Models WD tenders and they work and look well. However, I am at the mo' building a Finney tender, and because it is designed for the old simple compensation, it has inspired some thoughts. Short wheelbase 8-wheelers are less receptive to CSBs, needing either a lot of weight or very light spring wires, as the spans are so short. Springy equalisation rather than equalising springs!

My Finney tender uses two pairs of springs between the outer pairs of axles, similar to the way the design intended, but with spring wires rather than rigid beams. Soldering Gibson 2mm bore washers of 0.5mm thickness to Bedford bearing carriers provides both a bearing surface to carry the load, and suitable side control of the wheels. The compensation pivots are extended outside the inner frames to provide the fixed fulcrum, and allow the wheelsets to drop out when the brakes are hinged out of the way. This method shouldn't be difficult to adapt to the Easi-chas.

The wires used were originally .015", but they were changed to a softer .013". This may yet change once the body is finished..

Ted.
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grovenor-2685
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Re: Converting Tender Chassis

Postby grovenor-2685 » Sat Jul 21, 2018 8:10 pm

This is of course the springy beam approach covered by Digest 41 Figure 77(c). I have used it on the tender of a Bachmann WD with success. I used Comet LNER tender frames cut into two independent 4 wheel sections to allow the axle 2-3 interval to be shortened. This also allows the two sections to be electrically seperate and using wheelsets shorted one side gives simple electrical pick up from two wheels each side. I have also use the same principle for 3 axle tenders as shown in figure 51.
Regards
Regards
Keith
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zebedeesknees
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8 axle non-bogie vehicles with CSBs

Postby zebedeesknees » Mon Jul 23, 2018 1:31 pm

It would appear that my reasons for going to springy beams on the Finney 8-wheel tender have not been understood by some; Keith is right, the idea has been available to interested modellers for some time. In fact, one of my first P4 locos, an S&D 7F, had this feature and that was just after I joined the Society (2769). So I did not learn it from some self-appointed pseudo mechanical engineer.

That the Lanarkshire Models CSB WD tender chassis works perfectly well was clearly stated in my posting. My reasons for using springy beams in the Finney tender were, as stated, partly because Finney had designed in the pivot points already, which made the installation simple. I still may have gone for my standard CSBs if it were not for the difficulty in avoiding the water scoop mounting box and operating gear, which I didn't state, for brevity. Had Mr. Finney made it as easy to CSB as Dave Franks has with the WD tender chassis, then I would have gone that way.

Likewise with 8-coupled locos. My caveats about very short spans and weight do not apply, so they are definitely better (and easier!) sprung with CSBs.

Ted.
(A purists' purist)

J Gleeson

Re: Converting Tender Chassis

Postby J Gleeson » Sun Sep 02, 2018 3:51 am

Many Thanks to all respondents-this is my first P4 tender, and the ideas presented will be followed up.


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