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Post by Rex Hanman on Mar 24, 2011 14:24:14 GMT
I started to build one in 1970 as an a level project. You could do that sort of thing in those days. Finished it 27 years later! Don't let that put you off, I know of at least one that was built in less than a year, the original idea of the design. They are great little engines and go well when you get the wrinkles out. Mine once pulled 47 stone up a 1 in 100 at our old Redrice track. Haven't tried it at our new Wherwell track yet. There are several in the Andover club and we used to have a Rob Roy day. Must resurrect that now that we have a new site. My one tip....bring the steam pipes into the front (ends) of the steam chest rather than trying to squeeze them into the gap between the steam chest covers. Makes the connection from the lubricator easier too!
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sonicspeed66
Hi-poster
Happiness is a steam engine and an understanding wife....
Posts: 189
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Post by sonicspeed66 on Mar 26, 2011 9:21:16 GMT
Thats just brought a screech of the drill stooping I'm just at that stage of my build and hadn't thought of that .......looking in to it have you got a picture to show how you did it ?
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Post by drumkilbo on Mar 26, 2011 10:09:29 GMT
That's a great tip Rex, sadly too late for me. I started my Rob Roy in 1980 and did the wheels on a Unimat 3 but it was a struggle. I acquired a bigger lathe about 5 years ago [ Perfecto] and finally got round to machining the cylinders with a boring bar between centres.
Ian.
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Post by Rex Hanman on Mar 27, 2011 17:27:02 GMT
Will try to sort out a pic of how I did it. Bear with me. Another advantage is that you can remove the covers without having to remove the pipes which is a right fiddle!!
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Post by Rex Hanman on Mar 27, 2011 18:13:01 GMT
i251.photobucket.com/albums/gg299/hanmanr/IMG_0654.jpgOk, I've not posted a pic on this site before so don't know if this will work. ???It should be a link to photobucket where I've put a pic of the steam pipes on my Rob Roy. If I've done it wrong please would somebody advise me how to do it right. Another tip....fit the hand pump in the other tank....it's bigger as it doesn't have the reach rod behind it so more room to fit it and being right handed I don't have to put my arm over the safety valves when they are blowing off furiously and I'm trying to get water into the boiler! ;D
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Post by Rex Hanman on Mar 27, 2011 18:14:41 GMT
Ha! I think it's worked! Simples! ;D
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sonicspeed66
Hi-poster
Happiness is a steam engine and an understanding wife....
Posts: 189
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Post by sonicspeed66 on Mar 28, 2011 7:54:35 GMT
Hi and thanks this is a classic case of a picture speaks a thousand words and a few more ..... Just what i needed :(I'm off to buy a new steam chest as i had drilled one in the wrong place before i saw this or read about this idea.
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Post by doubletop on Mar 28, 2011 8:40:49 GMT
This may be of interest . www.homemodelenginemachinist.com/index.php?topic=9516.0I didn't build it but I finished it and have recently got it running properly. It briefly managed 5 up the other weekend (see links below) My Dad always said he'd made a mistake in choosing 3.5" over 5" as there's so many fiddly bits that need to be just right to get a good working model. He was an instrument maker by trade so was capable of making very fiddly bits. That is supported by how well it runs now. I'd imagine 5" should be far more forgiving. Pete www.youtube.com/v/5B0fDVx62o0www.youtube.com/v/dqCynkwWiOk
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Post by doubletop on Mar 28, 2011 8:46:13 GMT
......Another advantage is that you can remove the covers without having to remove the pipes which is a right fiddle!! Now you tell me!! take a look at the link I've just posted. I've lost count of the number of times I've had the steam chests apart getting the timing right. Pete
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Post by Rex Hanman on Mar 28, 2011 9:24:08 GMT
Yep! Precisely why I changed mine! ;D If you look carefully at the pic you can see where I have made plugs to blank off the original holes in the covers. Sonic..do you really need to buy new bits? There may be quite a few Robs around with this modification as everyone who sees it says they will do the same. Looking at the photo has made me realise what a sorry state she's in. I only ever had one derailment and it knocked off one of the draincocks hence there is no linkage on one side and the hideous great screw in the linkage is a "temporary" repair. Must sort it out. Looks like its time for a session in the works. Another change that I made was to squeeze in an axle pump instead of the crosshead pump in the design. I didn't like the arrangement and thought I could do better. Never designed or built a loco before...such arrogance!! You can just make it out in the pic. As for 3.5" being fiddly...too right! Interesting to note that you are looking at building a castle in7.25". I went the same way....GWR large prairie in the same gauge. Circumstances mean that I haven't touched it for many years but things are about to change!! ;D ;D ;D
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Post by peterseager on Mar 28, 2011 10:49:20 GMT
The consensus at our club is that Rob Roy is considered as a beginners loco because if you can build one you can build anything and if you can drive one you can drive anything!
We have two in the club. One built and driven by someone who must be a Rob Roy Grand Master and the other still being debuged after many years of building and now testing. It has been converted to an axle pump (as has the GM's loco) but still giving problems.
Peter
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Post by Rex Hanman on Mar 28, 2011 10:58:25 GMT
I think that's fair comment. I'm not sure that a Rob Roy is a beginner's engine but don't know what is. A tich is perhaps less work but you still have to make all the basic parts to the same accuracy and they're even more tricky to fire.
Maybe 5" is a better bet as less of a fiddle but there are so many other factors involved...cost, weight, etc. I agree though that if you can build a Rob Roy you could tackle pretty well anything with suitable equipment.
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Post by Nigel Bennett on Mar 28, 2011 12:01:05 GMT
Sure you can't plug the hole with a piece of gunmetal, silver-soldered in? (Tipp-Ex any adjacent holes or surfaces you don't want soldering!) I've lost count of the number of times I've done that because of holes in the wrong place, or because I've simply changed my mind where they should go.
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Post by Rex Hanman on Mar 28, 2011 12:39:24 GMT
The holes in the covers were already threaded, something like 3/8" x 40 if memory serves. I just screwed in some threaded blanks, maybe with a spot of suitable sealant on them.
One of the eccentrics has shifted, last time I ran (5 years ago?) it would only go backwards. Should be easy to do as I don't have to mess about with the pipes. Now that we have a track to run on again I will have the incentive to do it.
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Post by doubletop on Mar 28, 2011 18:53:17 GMT
................... Looking at the photo has made me realise what a sorry state she's in. I only ever had one derailment and it knocked off one of the draincocks hence there is no linkage on one side and the hideous great screw in the linkage is a "temporary" repair. Must sort it out. Looks like its time for a session in the works. ............. Having stripped mine down to the frames, twice now in the past year, and painted the frames three times I'd advise that it isn't as daunting as you may think. I've just checked my other post; this last time, when I had a few things to sort, took me from 9th Feb to 2nd March to get it stripped, frames etc prepped and powder coated and all back together again, with the issues fixed. This was evenings and weekends only. Taking the plunge allows you to get everything sorted rather than patch up jobs Pete
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steam4ian
Elder Statesman
One good turn deserves another
Posts: 2,069
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Post by steam4ian on Mar 28, 2011 21:35:22 GMT
G'day dan
Have a good look at Rex's photo of the front end; the loco not Rex.
Think about what you will expect the loco to do for you once it is built. Is it for the mantle piece or for club public days pulling a load of happy kids? Is it a stepping stone to something you really want to build or a retirement time filler?
If you must build 3.5" and it must be a beginner's loco then Juliet has a lot going for her. I know of one built by a 16 year old in 1965 that still pulls passengers.
If you want simplicity, reliability and pulling power then Barry Potter's 5" gauge Blowfly would be hard to top. I know it's colonial, but we colonist got a few things right, including all welded steel boilers see the A! thread.
Regards Ian
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smallbrother
Elder Statesman
Errors aplenty, progress slow, but progress nonetheless!
Posts: 2,269
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Post by smallbrother on Mar 29, 2011 8:24:42 GMT
I would have a look at the comprehensive archive at Station Road Steam, which includes many detailed photos of part built locos. There are Rob Roys and Scamps (which I have chosen as a starter loco). The 3.5" locos look far more fiddly and difficult but maybe you would see it differently.
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Post by doubletop on Apr 5, 2011 7:28:23 GMT
For an example of fiddly, the business end of my Rob Roy (this pic has the ash pan installed and not the gas burner)Pete
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cotswold
Part of the e-furniture
Still testing the water
Posts: 307
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Post by cotswold on Apr 5, 2011 9:57:31 GMT
Martin Evans, LBSC, Don Young, et al are of the "before PC" generation and designed valve gears empirically on the drawing board. Nowadays there are simulation programs available that will allow you to check before cutting metal. Or better still, buy Don Ashton's little monograph and check the valve gear by first hand re-calculation.
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Post by Rex Hanman on Apr 5, 2011 13:49:38 GMT
Mine looked like that once! I never got round to the brake gear though. I thought it was fiddly enough without it. Nice looking example, Pete, well done.
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