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Post by gingerneer on Jan 13, 2015 17:27:53 GMT
Hi dc309
I did not build her, more like i finished her off. She was a air running chassis and a complete but leaking boiler (pin hole leaks on 3 of the stays). I run her a couple of months with the axle pump as built then i reduced it in size. I re worked the blast nozzle, and the made the steam dyers radiant (going all the way in to the firebox). Other than that she is to the 'words and music'. As for the 'words and music' there is a PDF copy on the internet, if you search for John Tom Steam plans they are on the LBSC page. Even as a slip eccentric she is a cracking engine, free steaming and once you have the knack easy to drive.
Will
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dc309
Seasoned Member
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Post by dc309 on Jan 13, 2015 21:44:53 GMT
I looked on there as I'd seen it on there before but the link had been removed.
I'm just about to buy the cylinder castings... I can hear my wallet cringing from here!
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dc309
Seasoned Member
Posts: 146
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Post by dc309 on Jan 18, 2015 11:38:56 GMT
Not much progress made this weekend due to the weather... (It's bloody cold out there) but I managed to get the crankpins finished and pressed in. I'm quite chuffed as the wheel sets are complete bar eccentrics and straps now!
The drawings don't exactly give positions for the eccentrics, so I'm guessing they just line up with other parts once they are made up?
Regards Dan
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dc309
Seasoned Member
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Post by dc309 on Jan 23, 2015 14:38:46 GMT
Some of the expensive bits have arrived! Looking forward to getting these machined and in! Can anybody answer my last question as I'm a bit unsure? All help is greatly appreciated! Regards Dan
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Post by Deleted on Jan 23, 2015 19:18:14 GMT
Hi Dan------ don't worry about the actual positions of the eccentrics on the axle until you come to do the valve setting later on...What I might suggest is that you have TWO grub screws per eccentric ( One as per the drawing and the other say at 120 degrees apart )...This will allow you to have the eccentric fixed to the axle with the one whilst you "spot" through the other hole onto the axle ( or go slightly into the axle )..... Remember that you have slide valves and these are outside admission....There is a fairly large down-force onto the valve body which has to be overcome by the grip of those securing screws......Try to get the grub-screw that has a point on the end if you can as these make a good impression into the axle material....Pay close attention to detail when making the cylinder ports and valve gear parts and make sure that the two lifting arms are identical ie}--- drill and ream them as a PAIR, then ensure that they are parallel when assembled on the weighshaft ...... same goes for the two ecccentrics as well......................... If these items are already made then you really need to strip, wash and measure EVERYTHING at this stage ( later WILL be too late !!).......Thumbs-up and Mum's the Word, eh ??
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dc309
Seasoned Member
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Post by dc309 on Jan 23, 2015 19:43:02 GMT
Alan, you're a star! This is the answer I was hoping for. I've made the eccentrics this afternoon but they still require drilling and boring - do I need to try and do these in pairs?
Regards Dan
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Post by GWR 101 on Jan 23, 2015 19:55:07 GMT
Hi Dan, sorry can't help with the eccentrics as I am not making your version. One word of caution looking at your cylinder castings, if I recall are you proposing to fit drain cocks. My castings had bosses which extended towards the centre of the cylinder this gave more space for the bottom stud in the rear cover, not sure what your drawing shows. Also there is not a lot of space at the bottom between this stud/nut and the fixing for the guide bars. Hope this is of some help, regards Paul.
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Post by Deleted on Jan 23, 2015 20:42:17 GMT
Alan, you're a star! This is the answer I was hoping for. I've made the eccentrics this afternoon but they still require drilling and boring - do I need to try and do these in pairs? Regards Dan In a word -------- YES !!.. Ideally all 4 should be IDENTICAL....So either all made at the same time on one piece of bar OR, use a jig of some sort to hold each one with the same off-set ( either in the lathe or Vert. miller )... A DRO would be very useful here...................... Have you a tilting vice for machining the cylinder steam ports ??
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dc309
Seasoned Member
Posts: 146
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Post by dc309 on Jan 23, 2015 22:05:48 GMT
Thanks for that Alan - I'd already adopted Curly's method as written in his article of popping and throwing them in the 4 jaw, but they seem to have come out ok. If they don't work, I'll have to remake them! Crankpins are finally finished, but they are tiny! Here's a picture of one of the leading pins for an example: As mentioned above, I made a start on the eccentrics for Stephenson Link valvegear and one for the axle pump: I managed to get 2 done before management called time on my workshop time and insisted I went indoors to watch some rubbish on telly! I've got a couple of jaw marks in them, but I'm not overly worried (should I be?) as they aren't too bad: Pretty pleased with my progress today, hopefully back in there again on Sunday for a couple of hours to finish off Dan
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jma1009
Elder Statesman
Posts: 5,901
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Post by jma1009 on Jan 23, 2015 22:29:56 GMT
hi dan,
you have done a very good job there! i hate making eccentrics!
ideally the eccentrics need to be a tight fit on the axle material. this assists if fixed with grub screws to prevent them shifting. i have always used grub screws (HT type for use with allen keys) with the point ground off flat. this provides a better fixing from an engineering point of view - or so i was told when i made my first eccentric 32 years ago.
to go back to your query re the valve gear, both TICH and JULIET have been 'fine tuned' by the experts since first designed by LBSC. there is an article on an improved stephensons valvegear for JULIET with corrected suspension offset and a few other tweaks and improvements - though i havent been able to find it so far - can anyone else help dan in this respect? the original gear designed by LBSC has a number of foibles as found out by brian lee when he obtained indicator diagrams off his own in 1970.
cheers, julian
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Post by Deleted on Jan 23, 2015 23:14:45 GMT
Dan has a copy of the revised Juliet valve gear that I did for a friend some time ago as the friend was concerned about the accuracy of the LBSC version. It was redesigned using Don's spreadsheet and is a big improvement over the original version. See page 3 of this topic for the results John
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Post by Deleted on Jan 23, 2015 23:39:29 GMT
Great work there !--------- those aren't jaw marks at all----- technically they are known as}--- "Lubricant retention pockets"......... Just dress them off lightly with a fine file to ensure they have not left a raised surface......
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dc309
Seasoned Member
Posts: 146
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Post by dc309 on Jan 23, 2015 23:55:06 GMT
Thank you for your kind words chaps! Julian, I've made the eccentrics a nice tap on fit to the shaft so with the addition of some small flats and a couple of grub screws as per your suggestion, I think I'll be well away Many thanks to John, I have the revisions that he did for Juliet and all the articles by LBSC which he very kindly scanned in for me. Very much appreciated John! Alan, I'll do along with that one - It sounds a dodge to me Many thanks for your earlier comments on the eccentrics. Paul - I missed your comment before! My apologies! My drawings don't show anything for draincocks, but I'm sure I can work something out to put them in as I reckon they will be an added bonus. Cheers, Dan
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Post by GWR 101 on Jan 24, 2015 11:36:10 GMT
Dan no problem at some times it can be information overload, I have attached a couple of photo's showing the closeness of the slide bars to the rear cylinder cover. I over came the fixing problem by fitting the slide bars using counter sunk socket screws, if this is a solution you adopt you might want to consider getting the screws before you tap the holes as I found there was limited options on thread types. You will see from the second photo that the drain cocks are a reasonable distance back from the cylinder end on my version so not interfering with the bottom stud. The gear for these is still a work in progress as my drawings do not give any detail and I copied the design in LBSC's book. Hope this is of some help regards Paul
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Post by Deleted on Jan 24, 2015 11:44:53 GMT
Hi Paul---------- great photos and that's also given me some "proportionality" to use re}--- my Cadbury linkage......Hi DAN....No, not a "Dodge" but "Tested, Working, Alternative Technology".... at least that's what they called it(me) at my last place of Gainful Employment !!........... (You work it out, I'm already in Mr. Stepney's bad books !!).........
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Post by GWR 101 on Jan 24, 2015 11:55:55 GMT
Thanks Alan, the lamp in the background is in the bedroom......see some people are understanding of how important these engines are. Regards Paul
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Post by Deleted on Jan 24, 2015 12:26:39 GMT
Paul,
The Juliet drawings show the cylinder cover mounting bolts/studs rotated by 22.5° compared to yours so the problem you had with the slide bar fixings and the cylinder drain cocks shouldn't arise. The slide bars and the cylinder drain cocks will come between two studs rather than inline with them.
John
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Post by GWR 101 on Jan 24, 2015 20:35:12 GMT
Thanks John. Dan it appears you haven't got the same problems that I encountered, apologies for any inconvenience I may have caused but better safe than sorry. Good luck with your machining regards Paul.
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dc309
Seasoned Member
Posts: 146
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Post by dc309 on Feb 26, 2015 23:09:31 GMT
Just a quick bump to keep the thread up top! Not been able to get in the workshop of late with other things going on, but I've been doing little bits with CAD to try and sort it out and get it going. Not much of an update but the best I can do for now! Regards Dan
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dc309
Seasoned Member
Posts: 146
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Post by dc309 on May 22, 2015 11:42:28 GMT
Hi all, A bit of a lapse in progress but slowly getting myself back in gear and in the workshop. Managed to get the holes drilled for the cylinders with a little bit of thought on CAD for mapping them out - thank The Lord for DROs!! Regards Dan
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