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Post by bambuko on Jan 8, 2017 11:48:25 GMT
PITA with these short nose spindles is that they are supposed to fit both on the taper and the back/flat face. That means you have to get both the angle and large diameter of the taper accurate.
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Post by bambuko on Jan 5, 2017 14:03:12 GMT
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Post by bambuko on Feb 20, 2016 20:32:14 GMT
Yes, when I have drafted LBSC's Minx in CAD to have a good look at it, his instruction were to "... adjust to approximate position... and when correctly adjusted, mark frame holes on weighshaft bearings...", so I played with few different positions on CAD - it was remarkable how, very small changes in the position, resulted in messed up valve events (even I could see this ). I now got to the fourth part of Simon's articles about Joy gear in E in M and he is also most encouraging about Greenly's "corrected" valve gear and straight slides, particularly as applied to small gauges! Amother source, was couple of articles by K.N.Harris about radial valve gears in ME (Jan 1972)- interesting. I am overloaded with information and need time to digest it and play with and try to understand it (a bit at least), before I make use of it.
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Post by bambuko on Feb 20, 2016 16:15:03 GMT
...what an grand challenge - I wish you well. Don. Thank you Don! I do realise, that until I have something to show, I am yet another "talker" rather than "doer", so I appreciate your encouragement I am not familiar with 5" drivers, so it was purely coincidental BTW, this is what I have in mind (click for a full size): I am sure it is far from perfect as far as valve gear goes, but far more "doable" than some other options...
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Post by bambuko on Feb 20, 2016 14:51:04 GMT
Thanks Don, What I seek is ability to control (remotely RC)typically British inside cylinder loco in Gauge 1. They normally run around in circles like demented dervishes chasing a ghost with the owner in hot pursuit to tweak some control with a "hand of god"... My dream is Gauge 1 loco doing leisurly shunting in the yard, going back and forth with prototypical speed (with me at the transmitter). Like I said "adequate control" would be a lot more than what seems to be usual at the moment.
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Post by bambuko on Feb 20, 2016 12:41:04 GMT
I never said so! Don't you put words in my mouth I was hoping to read Duncan Webster article in detail as well (originally in 1997 ME) I found his simulator is very easy to use, but the link I have mentioned earlier in this thread, is full of missing pictures making it difficult to follow the article, so I might have to dig deep and buy back issues of ME from epay (unless someone has them?). and finally... (I know it is a scarilege for some) for Gauge 1 inside cylinders and inside valves on top, I feel strangely attracted to Greenly's valve gear. Compared to slip eccentrics I am sure it is perfectly adequate for what I want? Small gauges are full of compromises to make it possible at all, so one more is fine afaic.
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Post by bambuko on Feb 20, 2016 10:18:38 GMT
My back issues of E in M arrived today and it all looks most interesting. I will have enjoyable weekend trying to take it all in Thank you Don again, for pointing me in the direction of Simon Bowditch!
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Post by bambuko on Feb 17, 2016 14:06:07 GMT
Chris, I just happened today across some old ME with a series on designing radial gears, including Joy. 4052 10Oct97, 4054 7Nov97, 4056 5Dec97... Thanks John, the article is available for download, here on modeleng.proboards.com Just found it hereIn the meantime, I have checked "Engineering in Miniature" index, and found the following:
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Post by bambuko on Feb 12, 2016 23:00:08 GMT
...you havent stated what loco it is? ... I haven't mentioned it, because (although I am drawing a specific loco) I don't think it matters - the question is a general one for all Gauge 3,1,0 inside cylinder (typically British design) locos. By the time you add (out of scale) axleboxes, crankwebs, etc, the space available for the four eccentrics is rather small. Don't get me wrong - it is all doable, but the Joy gear offers practical, relatively simpler solution. OK, it would be yet another compromise and departure from prototype, but the smaller the scale, the bigger the compromises (in my humble opinion). ...i am sure your choice of loco will be of great interest plus add a gloss on the valve gear design... I have been reading up old issues of ME today with both LBSC's Minx and Don Young's 4F. I have also downloaded Charlie Docksteder's sim package. I think I have enough for now to get me going with the draughting on CAD. When I (eventually) have something to show I will come back and share and ask for comments/advice. It will take me some time, but luckily it is retirement hobby not a job
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Post by bambuko on Feb 12, 2016 15:17:15 GMT
Hi Bambuko, Those who know me well know that I don't take offence, even regarding your last comment... Good! because for a minute I thought you sounded like a very angry man ...If my name keeps cropping up it's because I am anxious to help where I can. Simon Bowditch has done pioneering work in fine tuning many of the Hackworth variants... That is the kind of lead I was hoping for - thank you. I will have to see if I can find out more about this chap and his work! p.s. (later edit): just found Simon's webpage...This sort of work may well interest those modelling in small gauges... Trying to fit full valve gear for inside cylinders (with valves inside, irrespective of whether on top, below or between) is very challenging. It has been done (as I have mentioned) succesfully, but I am looking for something simpler and Joy gear seems to offer it. Chris
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Post by bambuko on Feb 12, 2016 13:04:18 GMT
Not sure why I should be labelled 'anti-Joy's gear' for a) not including Joy in my book on Walschaerts' and Stephenson's gears (!)... I don't think you are "being labelled" anti-Joy's gear? (although I guess some of the replies might be suggesting it... I can't control contributors to this thread). Best to quote the source: I simply asked: I didn't comment on Joy not being included in your excellent book, and I didn't use your name in my original question. Not sure why I should be labelled 'anti-Joy's gear' for .... and b) failing to dive in and post when I have nothing to add... Again, I don't think anybody criticise you for "failing to dive in"? You are free to dispense your knowledge and advice as you see fit, and if you think you have nothing to add that's OK as well ...I haven't counted, but I think that my name appears in this post more often than that of David Joy - that can't be right!... It is indeed not right and I guess particularly annoying when people put words in your mouth and attribute to you opinions you have not expressed.
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Post by bambuko on Feb 11, 2016 19:56:23 GMT
...I recall seeing a simplified Joy gear in a book either by Evans or Greenly (more likely Greenly)... thanks Ian, and yes (I have both books). Both Greenly and Evans have a chapter about Joy valve gear, but I am not sure about their value? I used to be blisfully ignorant and happy when reading "the model engineering masters", but now (I am still ignorant) and full of doubt (when I read Don Ashton's views about them):
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Post by bambuko on Feb 11, 2016 0:54:00 GMT
...i agree designing a gear from first principles isnt easy unless it follows Don Ashton's excellent precepts!... and that's exactly my problem - Don doesn't say much about Joy gear... i hope ... isnt suggesting we should all go back to the days of slip eccentrics with 60% cut off .... that is precisely what I am trying to avoid, but it is not easy in G3 or G1 (although not impossible - see for example inside cylinders, with valves in between, and full Stephenson's gear in gauge O, by Clarry Edwards, as described in Dec 1991 article in "Model Railways")
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Post by bambuko on Feb 10, 2016 23:08:44 GMT
I wasn't going to post in this thread (in the modern interweb slang "thread necromancy" being frowned upon), but I couldn't resist liking both the topic and some of the comments, although as you say - it was rather difficult to follow...
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Post by bambuko on Feb 10, 2016 22:57:12 GMT
Thanks Julian, I thought that Nick's Q1 used Don Young's 4F as a starting point (at least that's what he says here) Don's comments and dislike of Joy's gear appears to be based on "full size" reasons. In smaller gauges, other considerations come into play. I thought that Charlie Dockstader's simulator covers Joy, but I haven't tried it yet, and anyway simulators don't design things for you (it's a bit like, being a CAD driver doesn't make you a designer )
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Post by bambuko on Feb 10, 2016 21:38:41 GMT
Thanks David, It's not a question of understanding (or the lack of it...) of Stephenson's gear. I am familiar with Don's webpage and have his book. However, in very small gauges it is much easier to use Joy gear (see for example Q1 designed by Nick Feast) for inside cylinder locos. OK, not true to prototype, but it works (apparently) fine.
Hence my question. I suppose I could just draw it and run it in simulator until I get somewhere...
ps thanks for the offer of Aspinall drawings - very kind of you!
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Post by bambuko on Feb 10, 2016 18:16:42 GMT
Small gauge loco with two inside cylinders and valves on top. Not wanting to get involved with watchmaking, I would like to try Joy valve gear, rather than Stephenson's. Mainly because Joy gear would allow me to avoid trying to squeeze four eccentric between cranks There are some designs that could be used as an inspiration (e.g. Don Young's 4F), but I would like to at least try and understand, rather than "copy and hope" Can anybody recommend good source, which would help me to understand and hopefully design Joy valve gear for small loco?
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"bare"
Feb 6, 2016 14:04:14 GMT
Post by bambuko on Feb 6, 2016 14:04:14 GMT
At last... a sensible explanation with a source quoted :-) Thank you Phil, you are gentleman and a scholar ;-)
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"bare"
Feb 6, 2016 12:52:59 GMT
Post by bambuko on Feb 6, 2016 12:52:59 GMT
Thank you Tim, for bringing this thread back on topic!
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"bare"
Feb 3, 2016 14:41:15 GMT
Post by bambuko on Feb 3, 2016 14:41:15 GMT
Look guys, you want to discuss your chips on your shoulders ... go somewhere else :-) Rest of you - thank you for constructive and interesting replies. I even enjoyed small detour to Ireland :-)
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