Wheelset Conversion for RTR Bachmann Class 20 Loco

Ross Logie
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Wheelset Conversion for RTR Bachmann Class 20 Loco

Postby Ross Logie » Mon Feb 18, 2013 8:16 am

Dear Members,

I recently bought a RTR Bachmann Class 20 diesel with the intention of replacing the wheels to P4 specification. There is an old article on the forum (Jan 2009) discussing this specific modification and apart from a little difficulty in removing the base-plate on the bogies it seemed a straight forward conversion; so said Nigel Cliffe and Dave Searle with photographs of a similar conversion courtesy of Keith Norgrove.

My experience, so far, could not be more different. My intention is to use an Ultrascale wheel conversion set and I enquired of Ultrascale if their wheelset came with instructions as to how to detach the base-plate. They advised they could not provide details but suggested that I contact Bachmann. This I did and by prompt email response Bachmann’s Service Team offered the following comment and I quote: -

“The bogie frame clips over the inner part of the bogie with the clips at either end. To remove, ease the clip away from the bogie inner by sliding a broad blade behind it so that it will come over the moulded protuberance on the bogie inner”

Some 45 minutes later and having endeavoured to avoid any damage to the delicate detail around the bogies, success in detaching the base-plate remains illusive. I emailed Bachmann again requesting:-

“a sketch of what the clips look like and more importantly where on each end of the bogie I would find them.”

While I’m awaiting a reply could I ask members if they could shed some light on the matter, particularly whose members who were the main players in the Jan 2009 forum discussion and Keith Norgrove who’s article provided the photographs.

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grovenor-2685
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Re: Wheelset Conversion for RTR Bachmann Class 20 Loco

Postby grovenor-2685 » Mon Feb 18, 2013 8:33 am

My photos are here, I can try and explain a bit more fully after work.
Keith

nigelcliffe
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Re: Wheelset Conversion for RTR Bachmann Class 20 Loco

Postby nigelcliffe » Mon Feb 18, 2013 8:42 am

I'd guess one of two things:

a ) Bachmann have changed things, so its not quite the same anymore. No idea if this is the case.

b ) You're being too gentle. These clips need a fair force to shift them. It's a lot easier to see and open with the bogie not in the chassis, but that also needs a fair bit of force to twist (as if loco on subsided track) the bogie to get it out.


Looking at the bogie from below, there is the central "solid" part which includes the covers over the gears on each axle. Beyond the end of the solid part are some legs which connect to the actual end of the bogie. The join line is just in-board of the solid part, on mine I can see a distinct step and change in colour of parts when looking from the side. Keith's upper photo shows the screwdriver aiming at this join line.

I can't remember if the clips are "handed". On some locos one of the clips is rectangular, the other has a triangular "closure" slope on it. If one is triangular, that's the one to attempt to open. Keith's photo suggests opening at the outer end of the bogies rather than the inner.


The main bulk of the bogie moulding is very solid and hard to break. The finer detail, particularly near the wheels, will need modifying to clear P4 wheels, so don't worry too much about it.



- Nigel

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John McAleely
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Re: Wheelset Conversion for RTR Bachmann Class 20 Loco

Postby John McAleely » Mon Feb 18, 2013 8:50 am

nigelcliffe wrote:You're being too gentle. These clips need a fair force to shift them.


That certainly matches my experience. I found removing these underframes a multiple-expletive task, and it took what felt like hours to achieve (much less, I'm certain).

Having now done it a couple of times, I can place a screwdriver in just-the-right-place and pop them off with only a couple of twists.

Keith's photos certainly helped me. I think that since that model, Bachmann have added brake rodding mouldings to the bogies. These fouled my ultrascales, and I ended up removing the rods (carefully, with a sharp scalpel) and replacing them with a strip of plasticard that sits outboard of where the moulding does.

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John Donnelly
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Re: Wheelset Conversion for RTR Bachmann Class 20 Loco

Postby John Donnelly » Mon Feb 18, 2013 9:18 am

John McAleely wrote:
nigelcliffe wrote:I think that since that model, Bachmann have added brake rodding mouldings to the bogies. These fouled my ultrascales, and I ended up removing the rods (carefully, with a sharp scalpel) and replacing them with a strip of plasticard that sits outboard of where the moulding does.


That's exactly what I'm having to do with mine...

John

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grovenor-2685
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Re: Wheelset Conversion for RTR Bachmann Class 20 Loco

Postby grovenor-2685 » Mon Feb 18, 2013 8:44 pm

b ) You're being too gentle. These clips need a fair force to shift them. It's a lot easier to see and open with the bogie not in the chassis, but that also needs a fair bit of force to twist (as if loco on subsided track) the bogie to get it out.

However, you need to avoid twisting the bogie to much while levering the clips off or the bogie might pop out on you, they do just clip in, but its easy to damage them when putting them back, and also when the bogie is out the axle of the worm wheel can easily drop out and get lost. So I would definitely recommend persevering with unclipping the bogie frames from the gearboxes with everything else still assembled. The screwdriver in my pic is a bit big, a jewellers style would be better and needs to be sharp enough to catch in the crack between the hoop on the bogie and the gearbox. I've annotated these two pics to try and make it clearer.
Class20-21.jpg

Class20-22.jpg

If you do want to take the bogies out, then it would be a good idea to open up the top of the chassis so you can see what you are doing, and you will have to anyway to make the wires safe when you put it back. The body lifts off after removing the two screws just behind the centre of the buffer beam at each end. Then you can take off the worm by taking out the 4 screws holding the square plate over the bogie, the worm comes off with the plate leaving the top of the gearbox visible.
See below.
20-1.jpg

Good luck, take care.
Keith

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John McAleely
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Re: Wheelset Conversion for RTR Bachmann Class 20 Loco

Postby John McAleely » Mon Feb 18, 2013 9:37 pm

It may be worth noting that Keith's pictures correspond to my (suspected to be newer) class 20 in the retaining details. So where to put the screwdriver, and what to lever over what is the same.

When you've dropped in the ultrascales, a dry run of re-assembly will reveal quickly which bits of the new brake detail mouldings need to come off.

Ross Logie
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Re: Wheelset Conversion for RTR Bachmann Class 20 Loco

Postby Ross Logie » Tue Feb 19, 2013 8:22 am

Dear Members,

My thanks to those who responded with their detailed comments, supported by photos from Keith Norgrove, they were most helpful. Now that I know what to look for as regards the clips, rest assured that I will use the necessary force to separate the inner and outer bogies. I am also grateful for the advice on how to detach the bogies from the main motor, should this become necessary and will succeed in fitting the drop-in wheelset, especially after the time you have taken on my behalf.

Thanks once again,

Ross Logie

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Mark Tatlow
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Re: Wheelset Conversion for RTR Bachmann Class 20 Loco

Postby Mark Tatlow » Wed Feb 20, 2013 4:50 pm

The trick with removing the Bachmann cosmetic bogie frames is to insert the screwdriver from above.

Twist the bogie to its maximum extent and the top of the clasp becomes exposed from above. A smallish (say 2mm) watchmaker's screwdriver can be slipped between the subframe and the cosmetic bogie frame. A quick twist and you are there.

It is the same feature on the class 24's and 25's, so I have had a lot of practise................
Mark Tatlow

Ross Logie
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Re: Wheelset Conversion for RTR Bachmann Class 20 Loco

Postby Ross Logie » Thu Feb 21, 2013 11:09 am

Dear Members,

I have successfully detached the bogies and removed the wheels and as the more experienced modellers have commented it is a relatively simple operation. Two or three minutes was all it took but that was only because I knew what to look for. I would also comment that force was hardly necessary, the key was in the detailed advice given and understood. Incidentally, I was amazed by the amount of grease in the cogs, I assume this is quite normal!

Now I'll order the P4 wheels, make some test track and run in my beautiful new Class 20 loco.

Once again, I appreciate the help.

Yours sincerely,

Ross Logie


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