jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Nov 27, 2013 22:54:54 GMT
Lewis Nodes of the Bluebell Railway recommends a type of rape oil for locomotive bearings. Low SAE engine oil (such as that used for lawnmowers) is ok. ive heard of people using chain saw oil before - not the sort of thing i would ever use on my locos. the cardiff club has a drum of the proper stuff as used in fullsize. never use ordinary motor oil - it is far too thin and full of stuff you dont want on steam locos. cheers, julian
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JDEng
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Post by JDEng on Nov 28, 2013 8:48:22 GMT
A few things to think about in response to the foregoing, Striplar:
a) The little end is far more highly stressed than the corresponding big end because it has a smaller surface area, is taking the same load, and only receives "boundary condition" lubrication because it only moves through an arc. A lot of full size engines had a solid bronze bush in the little end rather than a white-metalled one for this reason - I believe the same applies in car engines. I am not sure whether a ball or roller bearing would be appropriate because the point loadings on the balls or rollers would be very high and the bearing location would not allow them to "roll". I may be wrong but it's something to consider.
b) If you want to be prototypical with axleboxes they normally have a worsted oiler pad at the bottom to wipe oil onto the bearing, exactly like Suctionhoses felt pads. The best oil feed in theory is to allow the pad to do the oiling with no oil grooves in the brass; sometimes the oil feed is arranged to maintain the oil level in the keep with the pad as the sole means of transferring it to the journal. If you need to use oil grooves the LMS system was to have two grooves, one on each side of the brass just above the join with the keep; the other recommendation is to have one at either side at an angle (from memory - and I'd have to check to be sure) of 40 degrees. Oil grooves should always run along the journal (perpendicular to the line of movement) to prevent ridges being worn into the bearing surface.
c) Morris Oils or Hallet Oils do a range of steam and lubricating oils aimed at steam vehicles; Hallets in particular sell in small quantities and will give advice if you ask them. I'm with Julian on this, use decent oil, it really is liquid engineering and to use any old rubbish is false econonomy as far as I'm concerned.
Regards,
John.
PS: I knew you GWR bods thought Collet walked on water but I didn't realise his locomotives would float as well!! Ha!
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Post by Deleted on Nov 28, 2013 10:03:27 GMT
DEAR ALL}---- JDEng is known to me and this posting is entered "without prejudice".ie}-- not to be taken seriously !!!...............Hi JOHN-----------OH DEAR, NO !! ----- It was Churchward who walked on water.. "Charlie" was one of his Disciples who were to later spread "The Word" throughout the Pagan Railway world !! ( Similar in a way to Stroudley, Stanier, et al.)---------- here's some bedtime reading for you}------ www.steamindex.com/people/churchwd.htm ----------- If you scroll to the bottom and look at FRY, LAWFORD H. you'll se a reference to "Spherical leading crankpins giving 2&1/2" sideplay on the 2-8-0's".......... STRIPLAR please note...Joking aside for a min. and to keep a sense of perspective remember that the bulk of GJ's founding work was produced in the pre-TITANIC era......That's why whenever I do get the chance to visit YORK museum I make a point of just touching LODE STAR or CITY OF TRURO for a while and making that physical connection to those long-lost elegant Edwardian times....These engines pre-date the A4's, Black 5's, Merchant Navy's, etc by 30 or more years yet still look "modern", if you get my drift ??---------- OK, us GWR types do tend to "bang-on" a bit so I'll pull me head in now.......Anyone still talking to me ?
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pault
Elder Statesman
Posts: 1,497
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Post by pault on Nov 28, 2013 10:07:28 GMT
GWR = Gresley Was Right
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Post by Deleted on Nov 28, 2013 10:14:50 GMT
Oh dear ( Kif sigh )---here we go again---Greasley Was Re-educated ( Mallard's centre big end ??)-------------- stop, before we enter a time warp, closed loop !!
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Nov 28, 2013 10:45:33 GMT
yes i think Churchward's legacy is much greater than Collett's. to get sort of back on topic, SPEEDY is a most non - Churchward type loco and wouldnt have been approved of by the great old man. he never built any 0-6-0 locos when in office (apart from Holcroft's 1361 class re-design of the Cornwall Mineral Railway locos), never built a loco with outside valve gear, and the whole concept of the 15XX class is completely non - Churchward, being a non - standard loco apart from the boiler. they also werent a lot of use once built, and other locos did the job just as well. from a financial point of view they were an expensive mistake, and the GWR could have bought some USA tanks for a fraction of the cost. cheers, julian
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Post by Deleted on Nov 28, 2013 12:30:02 GMT
A look at this will show just how close the two designs were}---------- www.kentrail.org.uk/sr_usa_class.htm ---------- Indeed JULIAN it probably would have made better economic sense and buy some as per the Southern ( especially in the austere, post-war years) but when your railway company is virtually inundated with the generic 57xx type plus all the Wolverhampton types of a similar nature, it just seems ludicrous to authorise a "special" class dedicated to ECS movements at Paddington and 81a.....But then it was around the Nationalisation years ..so maybe there was a bit of Ex-GWR "Slush-fund" money being spent ??-----who knows ??.. At least 1501 is still barking at the scenery up here......... a true survivor !!
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Post by Roger on Nov 29, 2013 8:43:05 GMT
To be honest, as long as oil gets in and dirt stays out they'll last forever. Axle boxes are the largest and slowest moving bearing surface in the whole engine! The later-day American practice for driving boxes was to have just a small pad of white metal on top of the axle - for only about 30 deg each side of vertical centre line - and that was all. Roller bearings in bogies became common. Timken being a household name in rail engineering. Roller type bearings for side rods where used in some cases but they where quite complex to accommodate the alignment issues. A bush, drilled with a myriad of holes and free to rotate against hardened and ground surfaces (pin and rod) were very successful. (the Santa Fe Big End) Out of interest, Australia purchased some 4-6-4's from North British in the early 50's (Victorian R class). They had roller bearings. during the voyage to Australia the gentle motion of the ship caused slight movement of the rollers which "Brinelled" the races under the weight of the engine. They were all stuffed on arrival! Rolling bearings have to roll... Solid bearings it is then, with a large covered oil reservoir and a felt pad as on the plans. I've drawn out the scenario where the axle is lifted to give 1.3 degrees of movement up and down. This angle is reflected on the flanges of the hornblocks with the start point for that being at the axle height. There's a small portion of a 30mm radius there so it's not a sharp point. Having the narrowest point at the axle centre means that the axleboxes move the smallest amount axially when this movement happens because the centre of rotation is around the axle centre inside the horn block. My plans don't show any of this and there's not even a comment in the SPEEDY book. Presumably the fits are expected to be so sloppy that it's taken care of in a normal build. Who knows.
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Post by Roger on Nov 29, 2013 8:47:58 GMT
Hello all------------ here's a classic case of a "Brinelled" needle roller bearing from an automotive universal joint....The needles don't actually roll 360 degrees in use but oscillate thus giving that distinctive look when worn................. holdenpaedia.oldholden.com/images/3/3a/Uni_preview.jpg --------------- Ah yes, Brinelled... this is a nightmare problem for high speed spindles. We used to use ABEC7 or ABEC9 bearings up to 80,000RPM running with grease (yes, it is possible) and the slightest hint of applying a force through the bearing on assembly was enough to scrap them. At £80 a set and 16 weeks delivery times that wasn't something you could afford to happen very often. In case you're wondering if those were dentist drill sized bearings, they were SEB10s ie 10mm inside diameter. Now that's a challenge!
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Post by Roger on Nov 29, 2013 8:49:10 GMT
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Post by Roger on Nov 29, 2013 9:01:55 GMT
A few things to think about in response to the foregoing, Striplar: a) The little end is far more highly stressed than the corresponding big end because it has a smaller surface area, is taking the same load, and only receives "boundary condition" lubrication because it only moves through an arc. A lot of full size engines had a solid bronze bush in the little end rather than a white-metalled one for this reason - I believe the same applies in car engines. I am not sure whether a ball or roller bearing would be appropriate because the point loadings on the balls or rollers would be very high and the bearing location would not allow them to "roll". I may be wrong but it's something to consider. b) If you want to be prototypical with axleboxes they normally have a worsted oiler pad at the bottom to wipe oil onto the bearing, exactly like Suctionhoses felt pads. The best oil feed in theory is to allow the pad to do the oiling with no oil grooves in the brass; sometimes the oil feed is arranged to maintain the oil level in the keep with the pad as the sole means of transferring it to the journal. If you need to use oil grooves the LMS system was to have two grooves, one on each side of the brass just above the join with the keep; the other recommendation is to have one at either side at an angle (from memory - and I'd have to check to be sure) of 40 degrees. Oil grooves should always run along the journal (perpendicular to the line of movement) to prevent ridges being worn into the bearing surface. c) Morris Oils or Hallet Oils do a range of steam and lubricating oils aimed at steam vehicles; Hallets in particular sell in small quantities and will give advice if you ask them. I'm with Julian on this, use decent oil, it really is liquid engineering and to use any old rubbish is false econonomy as far as I'm concerned. Regards, John. PS: I knew you GWR bods thought Collet walked on water but I didn't realise his locomotives would float as well!! Ha! All good points and duly noted. The small end is going to be a tough call. Soft bearings are going to wear because they're too small and can't be adequately lubricated. Harder bearings will last longer but will wear the pin too. Ball bearings are a bit of an unknown but if packed with high speed spindle grease might survive because there's virtually no play so the pounding they get is possibly going to be less. I think that's going to be my first choice. I've sourced the largest ones I can fit which are 4mm x 9mm x 4mm so they're a reasonable size. I can always fit a larger pin and switch to a plain bush if that doesn't prove to be satisfactory. Mind you, all of the wear will be inside the ball bearing, so fitting a new one at less that £2 is no big deal. I'm really warming to that. I can see that the axle constantly pressing up and keeping oil holes closed is likely to be less effective at delivering oil that a felt pad on the underside. I might just say to hell with it and do both. I won't put an oil hole on the top centre though, I've drawn two, one in front and the other behind the centre line at about 10 to and 10 past the hour if you see what I mean. Thanks for the Hallet Oil source, I'll make a note of that.
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Post by Roger on Nov 29, 2013 9:12:09 GMT
DEAR ALL}---- JDEng is known to me and this posting is entered "without prejudice".ie}-- not to be taken seriously !!!...............Hi JOHN-----------OH DEAR, NO !! ----- It was Churchward who walked on water.. "Charlie" was one of his Disciples who were to later spread "The Word" throughout the Pagan Railway world !! ( Similar in a way to Stroudley, Stanier, et al.)---------- here's some bedtime reading for you}------ www.steamindex.com/people/churchwd.htm ----------- If you scroll to the bottom and look at FRY, LAWFORD H. you'll se a reference to "Spherical leading crankpins giving 2&1/2" sideplay on the 2-8-0's".......... STRIPLAR please note...Joking aside for a min. and to keep a sense of perspective remember that the bulk of GJ's founding work was produced in the pre-TITANIC era......That's why whenever I do get the chance to visit YORK museum I make a point of just touching LODE STAR or CITY OF TRURO for a while and making that physical connection to those long-lost elegant Edwardian times....These engines pre-date the A4's, Black 5's, Merchant Navy's, etc by 30 or more years yet still look "modern", if you get my drift ??---------- OK, us GWR types do tend to "bang-on" a bit so I'll pull me head in now.......Anyone still talking to me ? It's hard to take offence when I have no idea what you're talking about . I know nothing about the broad history of all the different types and characters that inhabited the murky world of our steamy past. I take my hat off to these pioneers who developed this technology with little to go on. I suppose it's no surprise that the big characters of the era and their stubborn egos were both a blessing and a curse. You still see some of this stubbornness even today in designs that are still fundamentally the same as they were made decades ago. They were poor then and they're poor now, but that's the way they make them and they'll never change. Some aspects of poor design are largely overcome by better materials or tighter tolerances but it's still poor design. We saw this a lot in PCB Spindle design.
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Post by suctionhose on Nov 29, 2013 9:51:40 GMT
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bhk
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Posts: 458
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Post by bhk on Nov 29, 2013 10:34:43 GMT
Lubrication of valve gear is something I have spent many hours pondering over, though many great engineers have gone before me I always like to think about problems in depth before researching letting the engineering mind run free.
Ultimately if I were to design the perfect engine, It would be a fly crank engine with all the motion work contained within a enclosed casing, the crosshead and small end having oil supplied at pressure to provide hydrostatic lubrication. The oil would be pumped round the system by a separate steam driven pump. Axle boxes would use self aligning roller bearings with automatic greasers fitted, suspension springs would be replaced with air ride units.
The more and more I think about it the closer I get to a modern diesel loco.
My point is that though modern bearings are a great option in modern machinery which is designed for them where accuracy and alignment is ensured, ultimately there terrible at dealing with the "fit and tolerance" and loading that we see in steam loco's.
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Nov 29, 2013 10:37:28 GMT
hi john, thanks very much for the martyn bane links which i am absorbing with much interest. also hallet oils which i wasnt aware of - ive used morris's of shrewsbury before -always very helpful.
hi roger and anyone else building LBSC's PANSY, LBSC was usually quite meticulous in his description of how to allow axleboxes to lift and tilt - curving the sides of the slot accordingly. when he came to PANSY he described some very nice split axleboxes then advised 'waggling' a reamer the size of the bore' in the axleboxes to allow them to tilt!! (thus ruining the bore!)i hope no one ever actually did this and instead curved the sides of the slot as per normal.
cheers, julian
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Post by Deleted on Nov 29, 2013 12:06:11 GMT
Hello all---------and Hi! STRIPLAR, I was just trying to draw your attention in that link to the 2&1/2" (2.500")sideplay allowed for on the leading crankpin via the use of a spherical bearing on the GWR 2-8-0 freight locos........ " Hard to take offence" ?? Sorry, you've lost me there.....Where's that one come from then ??.. No one's trying to cause offence, least of all me.....
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JDEng
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Posts: 384
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Post by JDEng on Nov 29, 2013 18:12:11 GMT
DEAR ALL}---- JDEng is known to me and this posting is entered "without prejudice".ie}-- not to be taken seriously !!!...............Hi JOHN-----------OH DEAR, NO !! ----- It was Churchward who walked on water.. "Charlie" was one of his Disciples who were to later spread "The Word" throughout the Pagan Railway world !! ( Similar in a way to Stroudley, Stanier, et al.)---------- Taken seriously; what's that then!! Interestingly enough I've just finished reading K J Cook's book on his time with the GWR - interesting and very clever chap - and, reading between the lines I'd say he didn't like Collet much either. Interesting what he has to say about axlebox bearings and clearances in general. I can't quite understand what you mean with your horns Striplar. Are you talking about putting a radius on the horn cheeks, the outside/inside flange faces of the horns or the flanges on the axleboxes? John.
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Post by Roger on Nov 29, 2013 18:56:09 GMT
Hello all---------and Hi! STRIPLAR, I was just trying to draw your attention in that link to the 2&1/2" (2.500")sideplay allowed for on the leading crankpin via the use of a spherical bearing on the GWR 2-8-0 freight locos........ " Hard to take offence" ?? Sorry, you've lost me there.....Where's that one come from then ??.. No one's trying to cause offence, least of all me..... Ah, I see. Yes, that's a lot of float, I wonder if that was all actually used up in daily running. The comment about offence was just relating to your friendly spat about the relative merits of the various locomotives and designs you were having with others, and whether anyone was still talking to you. I think that was your comment. I was just saying that I don't have anything to contribute to that exchange because I nothing about the subject. If you read back your post you'll see what I mean. I know you wouldn't intend to cause offence. Sorry for the confusion.
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Post by Roger on Nov 29, 2013 20:23:21 GMT
I can't quite understand what you mean with your horns Striplar. Are you talking about putting a radius on the horn cheeks, the outside/inside flange faces of the horns or the flanges on the axleboxes? John. The horns are parallel and the axleboxes fit snugly in the forward and backward direction. What I meant was that the groove in the axlebox faces can't be parallel. It's been suggested that it ought to be possible to lift one wheel 3/32" off the track while leaving the other one on the same axle still in contact with the rail. That's an angle of about 1.3 degrees. If you draw this out you can see that the tilted axlebox has two 1.3 degree relieved sections that would meet at a sharp point. The radius I refered to was a softening of that intersection. I've attached a quick drawing with a few notes to indicate what I mean. Don't take any notice of any of the default details in the title box, it's just been created to show the details of the model. Attachments:Main block drawing.pdf (48.1 KB)
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Post by Deleted on Nov 29, 2013 21:14:55 GMT
You can leave those inside faces off altogether if you want...The outside faces transmit the thrust from the wheel boss to the frames via the horns but those inners contribute nothing positive.......................Here is a wheel assembly from my Torquay Manor which is currently undergoing a Heavy Major overhaul at the main works of Bluestone Engineering......Yes, those proposed angles seem ok to me....Back in the day at Bridgnorth when machining axleboxes on the 1945 Ex-Admiralty War Department Vertical miller I would slew the box over using the thickness of a power hacksaw blade to get exactly the same effect you have on those drawings...... Attachments:
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