- This topic has 2 replies, 2 voices, and was last updated 10 months, 3 weeks ago by Andrew Fell.
November 4, 2022 at 5:43 pm #243341Andrew FellParticipant
I’m trying to figure out the best way to convert these. I’ve purchased a set of 10 coaches without lights, so there’s no problem removing the metal bar that includes the axle bearings. (I don’t see how EM gauge wheels would fit unless these are removed.) Filing the bogies so that the wheels won’t foul the bogie frames isn’t a problem. I’ve tried replacement bearings, but then the axle is too tight. I could try reducing the length of the axle, but I can’t help thinking there must be an easier way of doing this. Can anyone offer any suggestions?
November 5, 2022 at 2:53 pm #243344Richard StevensonParticipant
I converted two sets of SECR birdcage coaches a few years ago. These have a similar metal bar but a shorter 32 mm (8ft) wheelbase, so are not identical to those on the mk2f coaches. I was able to bend the metal bars sufficiently to just clear the faces of EM wheel sets. Shorter axles, about 25.25 mm long, were required. I have a lathe, so this job was no problem for me. It could probably be done, with care, by mounting the axle in an electric drill and using a fine file. The plastic bogie side frames were carefully trimmed back to just clear the modified metal bars, ensuring that the same amount was taken off each side and cutting round the locating pegs. These must be preserved to maintain alignment of the wheel sets. The existing hole behind each axle box was widened to accommodate the dimple which forms the bearing. There was a real risk of breaking through either side of the axle box, so I would not recommend trimming the side frames back further in order to accommodate longer axles.
The result was very free running coaches, which were demonstrated on the test track at the Didcot Skills Day in March 2020.
At the time I did not think that this method was suitable for a manual sheet as I used a lathe and it required very precise and time consuming work. It was recently suggested that there may be scope for “advanced modeller” manual sheets!
More recently, Neil Knowlden has developed a method using inside ball bearings and a 3D printed bearing carrier. This is the subject of a forthcoming manual sheet. A possible disadvantage for some is that the bearing carrier may obstruct the fitting of my favoured Alex Jackson couplings.
A possibility that I have not explored is to use an MJT bogie etch (other makes are available) with the Bachmann side frames added cosmetically.
In short, no, I do not think there is an easy way of converting these coaches.
- This reply was modified 7 months, 2 weeks ago by Richard Stevenson. Reason: General reference to Bachmann coaches deleted
November 6, 2022 at 12:37 pm #243349Andrew FellParticipant
Thanks for your suggestions, Richard.
I recently purchased a lathe on Ebay (under £30 and not very sophisticated, but it does the job) and I experimented the other evening with reducing the length of an axle. (Initially I used a regular file, but found it difficult to produce a pinpoint end to the axle – presumably because this part of the axle has barely any movement when rotating in a lathe. I solved this by using a disc on my Dremmel as the file, with the lathe simply there to ensure the filed axle remains perfectly symmetrical.)
I think I can do away with the metal bars completely. I purchased some wasted pinpoint bearings, which fit neatly into the axle hole on the plastic bogies once the metal bars are removed. The issue has been that with these in place, a standard 26mm axle is too long. So I think your suggestion of reducing axle length is the answer.
With the wheels stretched out to EM gauge, there’s just about enough room to accommodate them within the bogies without the need for filing (as long as the axle cups hold them precisely) so I may be able to get away without filing the bogies, or only filing a small amount.
I’ll start experimenting next week and see how I get on.
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