Many of you may be aware Compact Orbital Gears recently found an issue with two of the bearings in the Phasing Case of power unit 430 which they are refurbishing. This has been a job stopper for a week trying to source a replacement as the original manufacturer, Hofmans, went out of business in 1969, being taken over by Ransome & Pollard and becoming RHP now NSK. Another company have been trying to help but unfortunately have not been able to come up with the correct bearing, their equivalent had a wider shoulder on the race collar, and it would not fit into the machined bearing housing. They did offer to manufacture two for £1,065 plus vat and carriage from their manufacturing plant in Switzerland plus 10 weeks lead time. This timescale was unacceptable and would have cost us future work for the loco. Following several calls and email exchanges last week and Power Unit Engineer, Pete Stovanovic and his team carried out a search at the Barrow Hill Depot on Saturday 25th. Eventually, a box was found containing various geared shafts with bearings attached. It turned out it was a box which should have gone over with the stripped case from PU 415…. was this the solution? Pictures were sent to Orbital, and they were hopeful. A plan was made, and the decision was made to take them over on Tuesday 28th sooner than rely on a courier and cost.
Loco Hire Manager & Volunteer Liaison Officer, Mike Hallam-Rudd kindly drove over all the way to Rhayader in mid Wales, indicative of the lengths, literally, that volunteers will go to help the cause of the DPS. Tom Sharp at Orbital managed to get an NSK Engineer, Richard Robson from their Newark base to attend. NSK owns RHP who took over Hoffmans, the original manufacturer in 1969, hence the ’H’ in RHP. Also present was the Orbital engineer Neil who is working on the project for us. He is enjoying it and sees it as a challenge.
Long kept parts still usable
Long-distance Mike was shown around the workshops, what an amazing place it is, and they are still using a fair few 1960s’ machines which are performing well and, importantly, are still extremely accurate. Some of the parts they were working on made the larger ones in a phasing case look small!
The parts from Barrow Hill were unloaded and the engineers set about examining the shafts and bearings. Two of the shafts had the right size/type of bearings on each side of the cog. These are a perfect fit and carry the required NM No 942000 so we had now got replacements if they came up to standard. Neil went to remove one, unfortunately he couldn’t find the three-leg bearing puller, he then realised that the one they did have belonged to a colleague who retired a few weeks ago, so he was going to bring one from home the following day. Unfortunately, the housing for the bearing in hole 17 had some very minute markings on from being standing for a long time and had had an interaction between the bearing and the surface of the housing. Various options as to how this could be remedied were discussed. Eventually, a suggestion was proposed - why not remove one of the bearing cups from the case of 415. This is the engine sent to Paxman at Colchester (as part of the deal with VSOE Ltd) in 2000. This was done, the part cleaned, examined by all and was found to be in excellent condition.
The cup was fitted into 430’s case and the bearing inserted, still attached to the shaft which had been taken from Barrow Hill to Rhayader. It was a perfect fit and spun freely. The exercise will be repeated on the opposite side components. Richard has taken the
defective bearing away to find an equivalent component to replace the ones borrowed from 415’s kit of parts as they are going to eventually rebuild this one for us.
We have agreed that with no further delays the case from 430 should be ready for returning w/c 10th Feb. Spectrum Freight will be doing the move, and they will be collecting from the Depot and taking the phasing case from 423 for this to have the same attention.
So, if you wish to donate to this project via Go Fund Me please follow the following link. https://gofund.me/24e1bb56
A fruitful day
This exercise has been well worth it. Imagine just fitting the phasing case back to the unit and running it for a while before the defective bearing gave up, and we were back to square one with a cost of many tens of thousands of pounds of potential damage.
This was a most enjoyable day and a great learning curve on what to look for and where to look on bearings. It was well worth the 322 miles and 13-hour day. Richard is also assisting with the three bearings which John Pepper on the Great Central Railway requires for the exhauster from No.19 which was broken last May; two are worn and one broken in the incident. We hope to report on this soon.
Unbelievable – new Deltic pistons?
And finally, Tom Sharp dropped a nice bomb shell. In his earlier life he was a design engineer on making engine pistons. Now, bear in mind the Mk. IV Deltic piston is no longer made and come the day we might be able to rebuild a power unit, we may have need of this currently unavailable major component. He still has the knowledge, and they also have the facilities, plus he also has contacts within the industry. A complete power unit piston is being sent with the driver when he collects the phasing case. This is an extraordinary development and one which might well run and run.
Pics Mike Hallam-Rudd
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