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PostPosted: 21 Apr 2017, 12:48 
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Joined: 18 Mar 2012, 21:57
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This is a broadening of a conversation between David Withers and I regarding the R&R 40t crane MP3 (RS1004/40, ADE331159) resident at the Nene Valley Railway and cared for by myself and others.

For some time, when operating the crane, we've had a growing knock that we think is coming from the LH big end, so we took down both big ends for inspection. The crankpin journals are slightly under 3" diameter and both are barrelled by about 4 thou. The whitemetal bearings (measured when demounted) give about 10 thou clearance. These figures match exactly the reading taken by David about 12 years ago, so there's no recent deterioration.

The first question I have is whether those figures give any cause for concern. Our immediate reaction was that the barrelling is OK but the clearance figure seems a bit generous so we'll almost certainly redo them (the whitemetal surface has some rough-ish areas). Lubrication is through a grease nipple on the big end that is religiously topped up prior to every operating session.

That raises the second question. The NVR's fitters were strongly of the view that lubrication for a 3" dia x 5" (approx) length journal should normally be an oil feed. Looking at the original R&R drawings for MP3, the grease nipple is not shown and there is 'something' that could be an oil-pot on top of the outer half of the big end bearing. Looking at pictures of other R&R cranes (GW No2, DS35), and a picture of MP3 from 1951 there does seem to be 'something' (the pictures aren't very clear) in the same place. So was the crane originally built with oil lubrication and later modified to grease? I've heard anecdotal evidence (not specific to cranes) that BR did this sort of thing.

Any comments or thoughts most welcome.


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PostPosted: 22 Apr 2017, 10:31 
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A follow-up to my previous post here. Firstly, in the third paragraph I managed to misrepresent David Withers’ views regarding the barrelling and clearance. It is the NVR fitters, not David, who think barrelling OK but clearance too generous. I’m sorry for the confusion.

Secondly, the question of grease versus oil lubrication. It’s been confirmed that extant cranes GW No 2 and DS1580 are grease-lubricated on the big ends. GW No 2 is fitted with screw-top grease pots, believed to be original, and DS1580 appears to have a nipple between the fixing nuts, as does MP3.


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PostPosted: 05 Apr 2019, 22:37 
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Like locomotive axle boxes, I would have thought that whitemetal bearings would use oil as a lubricant. Grease would be used on 'brass' or roller/ball bearings.


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PostPosted: 06 Apr 2019, 10:09 
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The whitemetal bearings used oil . The oil lubricate used woolly or kapok to deliver the oil of the bearing house to the axel . On the whitemetal bearings are foresee of an x canal to oiling the bearing .


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PostPosted: 06 Apr 2019, 14:03 
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If I recall correctly the big ends of GWR 2 were originally oil lubricated and later converted (date unknown) to grease. Each big end is a large split brass casting with white metal insert, and a "Kingfisher" screw top greaser has been fitted where the trimming of the oil pot used to fit.

When built I believe everything was oil lubricated on No 2.


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PostPosted: 06 Apr 2019, 16:46 
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I no longer have the (weakish) evidence to hand but I concluded that the big ends on 1931 R&R crane MP3 were fed with grease from new, or at least from quite early in its life.

Peter Woad, driver from roughly the mid-1960s to mid-1970s, told me: "Regarding the big ends, they were always grease fed during my time with the crane and we never had any trouble with them, only had slight sideplay causing some noise".

Two or three years ago the NVR fitter tried replacing the greasers with oilers as he felt that white metal bearings should be oiled, but oil was thrown out of the pots during operation.


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