Horsetan Posted May 17, 2012 Share Posted May 17, 2012 Those driving wheels (SCOA-P pattern?) had a quite unique appearance. The spokes were a sort of side-on H-section. Link to post Share on other sites More sharing options...
N15class Posted May 17, 2012 Share Posted May 17, 2012 Unusual spoke arrangement with those wheels. Link to post Share on other sites More sharing options...
julesmwatson Posted May 17, 2012 Author Share Posted May 17, 2012 Hi Horse and N115 Class Yes, they are the SCOA-P wheels designs. They were developed in the late 1940s by the Steel Company of Australia Ltd (the P standing for F. C. Paynter, who patented the design). While a number of steam locomotives in Australia used them, I understand that the UK-based Vulcan Foundry featured them on several of their locomotive designs, which were eventually exported around the world. (The Vulcan Foundry made the J Class locos for the VR - so perhaps that is the connection...?) Julian Link to post Share on other sites More sharing options...
Krusty Posted May 19, 2012 Share Posted May 19, 2012 Yes, they are the SCOA-P wheels designs. They were developed in the late 1940s by the Steel Company of Australia Ltd (the P standing for F. C. Paynter, who patented the design). While a number of steam locomotives in Australia used them, I understand that the UK-based Vulcan Foundry featured them on several of their locomotive designs, which were eventually exported around the world. (The Vulcan Foundry made the J Class locos for the VR - so perhaps that is the connection...?) Julian A rather handsome example: Link to post Share on other sites More sharing options...
Horsetan Posted May 19, 2012 Share Posted May 19, 2012 The smokebox door is very LMS 8F.... Link to post Share on other sites More sharing options...
RMweb Premium kevinlms Posted May 20, 2012 RMweb Premium Share Posted May 20, 2012 A rather handsome example: Interesting that 5 were built with different brakes. Anyone know the difference & why? Kevin Martin Link to post Share on other sites More sharing options...
julesmwatson Posted May 21, 2012 Author Share Posted May 21, 2012 Hi Krusty, That looks like a fine machine! Do you model SA railways, or just happen to have this photo to hand? All, Well, there's been some 'discussion' within VR modelling circles about the modified wheels for the J Class kits. Specifically, the concentricity and appearance. While the wheels appear to run true to me, some others are not so sure (we're talking about very fine tolerances, hence the debate). Furthermore, the axles are slightly over scale, which carries through to the wheel hub. By way of technical explanation, I've provided the brief method in which the wheels were modified, together with a suggested alternative. Method Used The axles holes were opened up by turning in a lathe with a tapered reamer and then finally partially reamed with 1/8†reamer so that they were fractionally under 1/8’ with a slight taper toward the outer face. Hence the interference (push) fit and the small amount of plastic pushed out from the outer face of the centres. Suggested Alternative If the axles must be 1/8" diameter to suit your hornblocks, then find someone who has a set of collets (which includes 1/8") for their lathe, so that shouldered, concentric axles can be produced. Next step, make up the tyres from scratch and don't try and salvage the existing tyres. If the tyres are going to be bored straight through, then the appropriate bore is 13.8mm. This will also reqire that the wheel centres be reduced in diameter, which should only be done by pressing them onto a mandrel that has been turned in the lathe. All the wheels should be done in one go, because if the chuck is opened you will need to make another mandrel. While this small set back is a little disappointing, I am determined to get this 'right'. So it's back to the drawing board, so to speak. I'll be investigating the suggested method, with the intention to follow this procedure. Furthermore, I want to use the correct axle diameter - not doing so was an oversight on my part, I'm afraid. In the mean while, I've been moving forward, completing the cabs for both kits - some photos will follow shortly. Julian Link to post Share on other sites More sharing options...
Grovenor Posted May 21, 2012 Share Posted May 21, 2012 Interesting that 5 were built with different brakes. Anyone know the difference & why? IIRC part of the EAR at that time was still using Vac brakes for the trains so the loco brakes needed to be controlled by the train vac brake handle (A lot of earlier Uk diesels had similar arrangements). It would have been fairly soon after these locos were delivered that EAR completed the changeover to air brake and this feature would have been removed.Regards Keith Link to post Share on other sites More sharing options...
julesmwatson Posted May 25, 2012 Author Share Posted May 25, 2012 Hello All, After much consideration, I have decided to have another attempt at the driver wheels. I want to get this 'right', and the limitation of the inital drivers could not be overlooked. This development has also brought forward the purchase of a Sherline mini lathe. While I’d like to think that I could undertake the work myself, I‘m not sure that my skills would be up to the task for a little while – and I want to get cracking on the wheels... Therefore, I am attempting to locate a person in Vancouver who can undertake the works(outlined in my previous post). Indeed, I may already have already through another modelling friend (cheers, Andrew). In the mean time, I have been continuing the build with my attention turning to the cabs. As can be seen below, I have made a good start on the cab for the coal fired version. However, the oil burner cab is not far behind. Finally, I need to correct Horse’s assertion that the SCOA-P wheel design features a ‘H’ spoke cross section. In fact, it is a ‘U’ shape. The photo below may help to show this a little more clearly. Julian Link to post Share on other sites More sharing options...
billbedford Posted May 25, 2012 Share Posted May 25, 2012 Are these the wheelmakers you had in mind? Link to post Share on other sites More sharing options...
dajt Posted May 25, 2012 Share Posted May 25, 2012 Are these the wheelmakers you had in mind? Wow, those wheels are fantastic. Very impressive. Link to post Share on other sites More sharing options...
Horsetan Posted May 25, 2012 Share Posted May 25, 2012 .....Finally, I need to correct Horse’s assertion that the SCOA-P wheel design features a ‘H’ spoke cross section. In fact, it is a ‘U’ shape. .... Aha.......see, we hardly ever get to see the backs of these things. Link to post Share on other sites More sharing options...
julesmwatson Posted May 25, 2012 Author Share Posted May 25, 2012 Hi Bill B, Thanks fr that. I've seen that web site previously - they certianly seem to do a great job. I've contacted him for a quote out of interest. I'll contact my doctor soon after to see about removing a kidney...! Hey Horse, No problems. I'll call off the VR Modelling lynch mob... Julian Link to post Share on other sites More sharing options...
julesmwatson Posted May 28, 2012 Author Share Posted May 28, 2012 All, I've been laid up with a rather sore throat, so I have not had much chance for modelling over the last few days. However, I found an image on a web site that has a significant amount of historical information regarding the once mighty Vulcan Foundry(http://www.enuii.org/vulcan_foundry/index.htm). This is how the J Class (in this case a coal burning version) looked 'on the showroom floor' at Vulcan Foundry - when it had that 'new car smell'... Julian Link to post Share on other sites More sharing options...
N15class Posted May 28, 2012 Share Posted May 28, 2012 There is some fantastic stuff on that Vulcan website. Think I will be lost for a few hours. Link to post Share on other sites More sharing options...
julesmwatson Posted May 30, 2012 Author Share Posted May 30, 2012 Hi N15Class, Oh yes, plenty of train surfing to be had on that site...! All, Well the quote is in for a Sherline mini lathe so that I can finish up the driver wheels. I'm really looking forward to this work. Ii the mean time, the cab of the coal version has 'made contact' with its boiler (see below). I sat it on the oil's footplate to see what it looks like. Apart from some grotty finger prints and some not-so-square joints (ie not yet soldered) it's starting to take shape. Julian Link to post Share on other sites More sharing options...
julesmwatson Posted June 19, 2012 Author Share Posted June 19, 2012 Hi Everyone, Well I’ve been darting all over the place recently and, to my chagrin, nowhere near the modelling desk. But I’m back in the hot seat. After deciding to rework the driving wheels, I’ve invested in a Sherline mini lathe, along with several tools and fittings. I put the lathe together on the weekend and can't wait to get into it. I’ve had a good look around the internet but there seems to be scant little information regarding machining of steam drivers (in any gauge). So in an effort to ‘add to the literature’, I will detail my progress over the coming weeks. The axels must to be 1/8 inch diameter to accommodate the High Level Kit bearings. However, the axel stubs will be machined to a prototypical 7.5 inch diameter. The tires will be fabricated from stainless steel bar, using a Proto87 form finishing tool. The wheel centres (supplied by SEM) will be pushed onto the tires in the lathe to ensure a square fit. Looking forward to it. Julian Link to post Share on other sites More sharing options...
julesmwatson Posted June 20, 2012 Author Share Posted June 20, 2012 All, I had the Sherline initiation ceremony this evening. While I’m a novice, I can certainly say that it is a fantastic machine to use. I worked on some 1/8 inch solid brass bar, which will be used for the axles. The axles need to be 1/8 inch to fit into the High Level Kits standard size bearings. However, a shoulder will be machined on the axle stubs for the wheel centre to be pushed on to (ie 2.5mm in diameter to represent the prototypical 8.5 inch seat on the face of the wheel). For its part, the Sherline worked a treat. I actually managed to quickly and accurately create the 2.5mm seat, and push on a wheel centre. The shoulder was slightly larger than 1.6mm and the seat was equally under size Nonetheless, I was amazed at how quickly this was achieved. I purchased some ¾ inch stainless steel solid bar this evening, which will be machined into tires. I’ll turn my attention to these after I receive the P87 form tool from Australia and the axles are fabricated. Julian Link to post Share on other sites More sharing options...
Horsetan Posted June 20, 2012 Share Posted June 20, 2012 You'll be making your own P87 wheels - including the centres - before long! Link to post Share on other sites More sharing options...
sunbeam.20 Posted June 20, 2012 Share Posted June 20, 2012 Hello Julian Is the P87 tool HSS or is it tipped? Is it just for the flange or is it shaped to form across the whole tread? If it is HSS I would advise using a lubricant/coolant, turning the material at high speed, light cuts and feed. Obviously the aim is smoothly with the feed and at a rate that gives a decent finish, too quick and you end up with a scroll. With my efforts I generally use wd40 as a lubricant, putting a coat on between each cut as the current lathe does not have a coolant system. I would also centre the end brass and be using a live centre to support it. If you can, I suggest you machine the majority of the required form of the stainless while still in bar form, with the minimum material left for truing the tread once it is parted off and fitted to the wheel centre. This gives it the maximum support/strengh while working, and gives a much reduced load on the wheel centre later. Once the tread is pressed onto the centre then mount the wheel on the brass bar to finish. The press fit is not so important here I feel if you will be picking up power off the tread, as the two can be fitted together with epoxy or a loctite product. I would use loctite, especially if you do not have a press, or the eqipment to accurately measure the diameters required for a press fit. And no, I do not consider verniers adequate. Another suggestion would be to perform the same operation for all, then move onto the next step as this gives a much reduced setting up time, instead of finishing a wheel at a time. Matthew Link to post Share on other sites More sharing options...
Horsetan Posted June 20, 2012 Share Posted June 20, 2012 Was there any particular reason for using brass for axles instead of steel? Link to post Share on other sites More sharing options...
julesmwatson Posted June 20, 2012 Author Share Posted June 20, 2012 Hi Horse, Yes, I can see me making the whole thing...eventually. As for the axles being made from brass. No particular reason. Your thoughts? Hi Matthew, Thanks for your thoughts on the matter! Much appreciated. I was intending to do as much work on the tyres before parting off the bar, as you suggest. Any finishing work was going to be completed with a four jaw chuck/mandrel. Given that the centres are not fabricated from metal, I am loathed to undertake any machining of tyres after they have been pushed onto the wheel. I intend to form a 'lip' on the front of the tyre, which the centre will seat up against (as was the design of the original tyres). Also, my understanding is the wheel centre is already concentric. So as long as the axles are straight, the tyres also concentric, and the push fit undertaken with correct tools, then she'll be apples. Your thoughts? Cheers, Julian Link to post Share on other sites More sharing options...
N15class Posted June 20, 2012 Share Posted June 20, 2012 Hi Horse, Yes, I can see me making the whole thing...eventually. As for the axles being made from brass. No particular reason. Your thoughts? Hi Matthew, Thanks for your thoughts on the matter! Much appreciated. I was intending to do as much work on the tyres before parting off the bar, as you suggest. Any finishing work was going to be completed with a four jaw chuck/mandrel. Given that the centres are not fabricated from metal, I am loathed to undertake any machining of tyres after they have been pushed onto the wheel. I intend to form a 'lip' on the front of the tyre, which the centre will seat up against (as was the design of the original tyres). Also, my understanding is the wheel centre is already concentric. So as long as the axles are straight, the tyres also concentric, and the push fit undertaken with correct tools, then she'll be apples. Your thoughts? Cheers, Julian Only problem of using brass is the brass bearings. You should use a harder material for the axle, this way the bearing wears and can be replaced. Your brass axle will wear with the bearing and need to be replace together. Two materials the same will also wear quicker than different materials working together. EDIT Best to use Silver Steel. Link to post Share on other sites More sharing options...
julesmwatson Posted June 20, 2012 Author Share Posted June 20, 2012 Hi N15 Class, Thanks for the metallurgical lesson! I guess the clue being that all other axles I've seen are made from steel... Back to the shop for some more material. Julian Link to post Share on other sites More sharing options...
45609 Posted June 20, 2012 Share Posted June 20, 2012 Hi Julian Unhardened 1/8" ground silver steel is what you want as N15 suggests. You're using an 8mm Sherline collet that should hold the work nicely concentric so all you will have to do is turn the stub on each end. Silver steel will need a little more practice than brass to turn to a nice surface finish and as I can't see any sort of power feed on the Sherline this will be the variable factor. Try to hone the tool with a slight radius on the tip. It will improve the surface finish but keeping in mind that you'll need to minimise this for the wheel centres to seat properly on the stub shoulder. For a finishing cut, when turning 1/8" silver steel with HSS, you'll need the lathe spindle to be doing about 1500 RPM. Cheers....Morgan P.S. I've been following this loco build with some interest. Fascinating stuff. Link to post Share on other sites More sharing options...
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