Lisa
Statesman
Posts: 806
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Post by Lisa on Sept 26, 2015 9:30:57 GMT
I know conventional wisdom says to use different oils, but the result of various experiments over 20+ years of commercial operation (at one point 8-10 hours a day, 7 days a week, for about 4 years) of 5" steam showed that it's better to use steam oil for the bearings. The result was a significant reduction in wear; one loco with southern valve gear needed its bushes replaced weekly with a thinner oil, this became quarterly when steam oil was used. The consensus being that on a small loco the heat transfer from boiler/firebox/cylinders is considerably more than on a full sized loco; thus warmer bearings thin the oil more, requiring a thicker oil to begin with to counteract the effect to ensure adequate lubrication.
An added bonus being not having to worry about mixing oils up when there's only one.
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Lisa
Statesman
Posts: 806
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Post by Lisa on Sept 26, 2015 7:23:18 GMT
Not much progress the last couple of days, as the usual late september cold snap has made the workshop a less than desirable place to be during the evening/night, which is when I usually work down there.
As such all I've done is cut some steel to size for the brake hangers, and pivot pins for same; I'll turn or shape these over the next couple of days as appropriate.
On the subject of oiling the loco, my current thoughts are to fit a twin ram mechanical lubricator between the frames just behind the front buffer beam. One ram would then feed the cylinders, while the other would pipe out to oil the axles and valve gear. The original design calls for a displacement lubricator, but I'm just not a fan of those. Not sure how to go about driving a mechanical lubricator though if it's located there, as while I could drive it off the valve rod, I've always avoided this; any reduction in valve travel from notching up (not a problem with slip eccentrics, but better to plan ahead in case I fit proper valve gear later) results in a corresponding reduction in lubrication. Another option would be to mount the lubricator on the running board, in front of the side tanks, it could then be driven off the cross head.
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Lisa
Statesman
Posts: 806
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Post by Lisa on Sept 23, 2015 14:01:40 GMT
Hi Pete, and Shawki, thanks for the welcome.
Pete; building a 5" gauge Flying Scotsman was somewhat of a childhood dream for me, before I got more interested in narrow gauge, still maybe one day.
Shawki; yes I'm up near Brisbane, not far from Grandchester MLSA.
A mildly amusing Blowfly related tale: about 18 years back my dad was discussing the design with a fellow (QSMEE) club member, and enquired as to how you'd oil the valve gear. The other guy, a well known boiler inspector, took a look at the GA - inside valve gear, side tanks, no frame cutouts - and replied "stand the b*****d on it's end."
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Lisa
Statesman
Posts: 806
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Post by Lisa on Sept 21, 2015 19:32:23 GMT
Hi everyone, I've just been looking at some of the threads here instead of working on brake gear. I've recently started looking after my elderly dad full-time, and have taken the opportunity to restart work on a 5" gauge Blowfly 0-4-0T seeing as the remnants of the workshop are available to me. Remnants, as dad sold most of it all off when his health began to decline. So it's been about 10 years since I last worked on a steam loco (rebuilt dad's modified Sweet Pea just before he sold it), and even without the machine tools needed to finish the loco it's nice to get back into model engineering after so long. The pic' below is what I'm starting with; I got as far as a rolling chassis before this was put away. Valve gear is slip eccentric, which is complete (a grand total of 2 rods). Currently sourcing some BMS for the coupling rods, and working on the brake gear - which isn't actually a part of the original design, but makes sense to have, and is a good re-entry point I think.
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