Richards Workbench, Heljan 31s and JLTRT Class 40s

[richard carr]

I'm not sure at this stage, the peak and 40 bogie are very similar and I'm hoping that when I convert my 46 to S7 I will be able to make this work without doing a fresh etch. If it just won't work without a lot of effort then yes I will do another etch. Simon T has bought a set for his peak as they are now so he might be able to tell us soonish.

Richard

 

[Steph Dale]

The red areas are covers to protect the bearing slide surfaces.

Mick,
Yeah, Bulleid's ruddy oil baths even made it on to diesels...
Steph

 

[richard carr]

Mick

I have no intention of moving the bogie pivot point, it works just fine as it is and would be a major pain to alter the body floor.
From a model point of view though it would be better if the pivot point was exactly central on the bogie, I'm not joking about the DJH 47, I tried 3 point compensation but the pivot is between the first 2 axles and all the weight goes on those and virtually non on the rear axle. In the end I have gone for a rocking axle on the first axle, a fixed rear axle and a floating centre axle, thankfully it works fine.

Richard

 

[SimonT]

Morning All,
I built one of Richards etches after seeing his first one on the train set at Nottingham. I wanted to re-use the existing metal 'cosmetic' parts of the Peak bogie and place them onto Richard's working inners. The more I looked at it, the more trouble I had with establishing the datums that would tie the two bits together; Richard's inners go onto the JLTRT plastic perfectly and I recommend them to all.

However, ..... I decided to have a go turning my two prototype bogies, which have run on the loco perfectly for two years, into etched perfection rather than bodged inners. The principal of my inners is fixed rear axle, the two other driven axles running in bearings on the compensation beams, and a pony truck for the leading wheel. I drew everything up in Rhino and played with increasing the pivot of the pony truck with an extension that ran back over the top of the inner to midway between the two leading axles. Not very elegant. I then remembered an old linkage the points the two links back to the desired pivot but which only go halfway back. This allows the pony truck to have a long swing in a small space. Slightly large pivot holes allow a degree of vertical movement and lead strip is glued down on top of the pony truck to keep it on the rails. The loco is now back in service on the Beeg and goes around all the bends; it even goes into the yard where it never went before.

Here it is before getting dressed.



Richard/Mods. If this is dragging things down a rabbit hole away from Richard's work bench, please move this to my workbench thread for any more Peak bogie discussion.

All the best

Simon

 

[ZiderHead]

I like the swing links - JLTP

 

[alcazar]

Fascinating topic.

I intend having a Peak, but will the etches work for OFS, or must they be for S7?

 

[richard carr]

Simon

Its all good stuff very happy to have it as part of my thread.

So it that the original bogie that has been modified ?

Richard

 

[SimonT]

but will the etches work for OFS, or must they be for S7?

What is the back to back on finescale? I can then take a look at the drawings.

original bogie that has been modified

Your bogies are in storage for the Great 40 Project. The original JLTRT metal cosmetic bogie just needed a front cross member changing and three holes to be drilled.

This inner is a new etch in .55mm NS to S7 standards. It would make sense to provide for finescale. The reason I ask for the back to back is the range of finescale spacers I have seen in kits seems very large. I'll try to strip the Peak down and photograph the finished bogie. There is no pivoted mounting on my bogie, JLTP!

Simon

 

[OzzyO]

Not particularly but it works well enough as it is.
I agree it would work better if the bogie/body pivot was in the centre of the bogie but that would require a big nut coming up in the centre of the cab !
Richard

Hello Richard,

we seem to have got out lines crossed here. I was not talking about moving the bogie pivot point, as that is correct (I did know that). But inserting a comp. pivot point between the front and centre drivers. That was why I mentioned the Y end to the compensation beam. The other way would be to have twin beams between them the same as between the two rear axles.

I'm a bit surprised that the bogie does not show a front end down appearance if you have not taken into account the difference in the wheel Dia. 9" or approx 5mm in 7mm. I would have thought that you would have had to add a 2.5mm packer to the underside of the front compensation beam on the pony axle.

I did mention about the weight that would be on each axle bearing / comp. beam running point of approx. 6.5 oz. This could cause a lot of wear at these points, have you considered adding a wear strip of something like Phos bronze or nickel silver at these points?
I only mention this as these points are going to be high wear points (unless you have gone for hard brass in your etch). I don't think that you should have the same problem with the axles running in the horn keeps as long as you keep on top of lubrication (a good graphite grease should work).

All of these points are not meant as bad, but too try and help you make what is good a bit better.

Engineering head taken off,

OzzyO.

PS. just spotted the question about the F/S B2B it is or should be 29.2mm, that's what Slater's work to.

 

[richard carr]

Ozzy

I'm sorry, I'm still not sure what you mean about the comp pivot point ?

You are right about the potential high wear points, I will be keeping a close watch on these with plenty of lube as these locos will see a fair bit of use over time.

As for not taking the differing wheel sizes into account I will need to check the CAD drawing, the original one was done about 3 years ago so it is possible that I did factor this in. WOuldn't the difference be 2.5mm as its the difference in the radius as opposed to the diameter that matters ?

Richard

 

[richard carr]

Mick

I'm just looking at your drawing of the 40 bogie, how thick are the wheels ? I did mine as 3.15mm but in the drawing they look even thinner than that.

Richard

 

[SimonT]

Ozzy,
thanks for the measurement, I'll have a look at the drawings later.
Simon

 

[OzzyO]

Ozzy

I'm sorry, I'm still not sure what you mean about the comp pivot point ?

You are right about the potential high wear points, I will be keeping a close watch on these with plenty of lube as these locos will see a fair bit of use over time.

As for not taking the differing wheel sizes into account I will need to check the CAD drawing, the original one was done about 3 years ago so it is possible that I did factor this in. WOuldn't the difference be 2.5mm as its the difference in the radius as opposed to the diameter that matters ?

Richard

Hello Richard,

I was talking about adding a second compensation (comp.) pivot point between the first and second drivers to give you the true three point compensation on your drivers, then by using the same beam that you have now from the front driver to the pony wheels.

I did mention that the wheel dia. was 5mm different, that was why I mentioned about adding a 2.5mm packing piece (packer) to the under side of the compensation beam on the pony axle (only).

You may have adjusted the pivot point down by approx. 1.7mm to compensate for the different wheel sizes, but by doing so all you are doing is removing tractive weight from the drivers.

I'll do some sketches to try and show what I'm saying.

OzzyO.

 

[richard carr]

Ozzy

I already have true 3 point compensation, there is one beam between the rear 2 axles on each side of the chassis each with their own independent pivot point, the third beam is then between the radial truck axle and the first driven axle.

Richard

 

[richard carr]

Mick

Thanks that confirms what I thought it was. I'll keep an eye out for the package

Richard

 

[richard carr]

Mick

I have only ever found one reference to the thickness of loco wheels and that was in the LNER green book on A3s where it states the driving wheel thickness as 5 and 3/8 inches which scales to 3.15mm. I'm told that GRW loco driving wheels are a little thicker and scale to 3.54mm. I did my 9f ones to 3.15mm and they work fine.
I suppose we should go and measure a 9f to see just how thick they are.


Richard

 

[SimonT]

The RCTS history of the standards Vol 4, appendix 5 shows the 9f wheels to be 5 1/2 inches and 5 11/16 inches for the centre flangeless driver. I make that 3.21mm and 3.31mm.

 

[Eastsidepilot]

When I re-pr0file wheels for S7 I find that the recommended min. of 3.16mm is difficult to obtain with Slater's wheels as having taken material off the back, to slim the flange down, you do not want to take too much off the face as the lip of the tyre covering the plastic can get very thin. So the max. of 3.26 or even 3.35 is ok.
All metal wheels are not a problem. I have found that most Loco wheels (steam) can be any where between 5 1/2"-
5 3/4" (3.2- 3.35mm)
Coach and wagon wheels are narrower.

Col.

 

[richard carr]

Work has progressed a bit further as I have started to put the body together. The first thing to do is to put the nuts to hold the body to the floor in place into the loco sides. These are force fit and I use a vice to push them home like so







Once you have done this you can use the floor as jig to help glue the sides and the roof and the cabs together, here they are just screwed together



Looks good already, this is going to be 40138 in 1981 condition, so the water tanks have been removed but it still has all its multiple working connectors and all 4 sand boxes per bogie.

So to glue it all together first screw the sides to the floor



The most important thing though with these kits is to make sure you remove every little irregularity, the will not be many but there are some, here are some on the roof.



You can see the little bit of excess resin make sure you remove it with a file. Once you have test the fit carefully. One problem you get with resin is that the long pieces like the sides and roof can be slightly different lengths probably due to how they cooled on the day they were made. Try lining them up at both end as one end will be better overall than the other. If you still end up with a big difference ie 1mm or more send the offending part back for another one even 0.5mm might be too much.

 

[richard carr]

I have now been building up the other pair of bogie frames and putting the other set of driven wheels together with their delrin sprockets



Here I'm using the taper pin reamer to cut the hole for the taper pin



You can just make out the hole in the sprocket, before you try and drill it you need to start the hole manually with a drill in pin vice otherwise it just bounces off the delrin



You can see the holes clearly in this one.
You need to remove some of the side frames to get enough sideplay I used a rasp to do this and then finished off with a big file. Even in finescale if you use slaters wheels you will need to remove some as slaters wheels are 4.5mm thick, mine are only 3.15mm thats an extra 2.7mm so even wider over the wheel face than S7.


There's the rasp and one one of the thinned side frames there was also a bit of excess resin on the buffer beam of the bogie not much but you do need to check these very carefully to make sure you get a good fit.



If you enlarge the picture you just see where I have removed it

You also need to remove the fixing lug on the rear part of the bogie frame





I then glued everything together and fitted the sandboxes. 40164 doesn't have rear one but 40138 does. The one thing that I thin could be better with these kits is the quality of the white metal castings, they seem to vary from poor to acceptable



These aren't too bad but they are nowhere near as good as those from DJH or MMP.

Here are the bogie side frames, the whole on the side frames for the rear sandbox is too far forward and should be like this



A bit of filler covers up the wholes on 40164.