Simond Posted January 25, 2018 Share Posted January 25, 2018 Phil I’ve not tried it, but the Zimo instructions indicate that there are small, servo-capable, decoders around. Alternatively, radio control... Best Simon Link to post Share on other sites More sharing options...
Giles Posted January 25, 2018 Share Posted January 25, 2018 For this, your lifting links drop, and the radius rod falls for forward, and up for reverse (these having slide valves) I admire your ambition, but you're on your own with that one! Link to post Share on other sites More sharing options...
Simond Posted January 25, 2018 Share Posted January 25, 2018 Ye gods! If the man that built the working road crane doesn’t fancy working valve gear, it must be a challenge... Best Simon Link to post Share on other sites More sharing options...
PhilMortimer Posted January 25, 2018 Author Share Posted January 25, 2018 As I said, it is purely a flight of fantasy and probably won't happen. I'd like to see if I can get the mechanical parts (i.e. movement of the radius rods) to work on the power units (just because), but servo's may have to come later. Or more likely, not at all. I think trying to really make this work may just push me over the edge...... Link to post Share on other sites More sharing options...
Simond Posted January 25, 2018 Share Posted January 25, 2018 Well, don’t do the servo, simply connect the cab lever up to the motions fore and aft... Oh, sorry, coat, hat, etc... Link to post Share on other sites More sharing options...
PhilMortimer Posted January 26, 2018 Author Share Posted January 26, 2018 Power reverser, rather than manually operated. And I aint making an operating power reverser! As an aside, i've always wondered how the reverser linkages between various units on articulated locos operate in order to prevent the reverser settings at the valve gear from being influenced by the relative movements of the adjacent parts of the loco. This problem exists not just for Garratts, but also for Mallets, Farlies, Meyers, etc.... Link to post Share on other sites More sharing options...
Simond Posted January 26, 2018 Share Posted January 26, 2018 I only cabbed a Fairlie on the Ffestiniog, never worked on them, so I’m not sure, but my guess is that the relative movement of frame and bogies is actually not very great, in the sense of changing the cutoff significantly. I suppose that they must have allowed enough clearance at full gear that nothing got stretched or bent. Best Simon Link to post Share on other sites More sharing options...
sir douglas Posted January 27, 2018 Share Posted January 27, 2018 (edited) things like this have always puzzled me as well, ive got a works drawing for a resau breton mallet ina an issue of NG&IRM review but i could never work out the compensation for the brake rodding this pic shows a braket on the middle of the valve gear cross shaft https://www.whrsoc.org.uk/WHRProject/2014/20140118-la-02.jpg a unique case as far as i now was on the Darjeeling railway and which i can only assume was becasue of the very sharp curves was fitted with a rotary shaft for the reverser http://www.lasergang-shop.de/kreativmeile/sites/default/files/users/user3/Darjeeling/Darjeeling-Garratt_07_620.jpg in this pdf shows a drawing of a FR fairlie, on the left hand bogie the reverser rod is just one long curved rod from the valve gear to the bottom of the lever under the footplate, and like wise the brake rodding too shownon the right hand bogie. there must not be any problems with it after running like this for 140 odd years Edited January 27, 2018 by sir douglas Link to post Share on other sites More sharing options...
PhilMortimer Posted January 29, 2018 Author Share Posted January 29, 2018 Thanks Sam. The rotary shaft mechanism I can unnderstand. Still looking for diagrams of lever / rod arrangements.I spend too much time studying the rebuild of UP 4014 in the hope that such details may surface. Coupling rods were re-installed on the garratts last night and I have installed the first valve guid and sub-unit of the VG to one of the chassis. Quite a bit of fettling was required to get everything to waggle correctly and freely with the radiius rod the neutral position. However, I now know what is involved and hopefully things will proceed a bit faster with the rest of them. 1 Link to post Share on other sites More sharing options...
PhilMortimer Posted January 31, 2018 Author Share Posted January 31, 2018 Slowly plodding on with fitting the valve guides and front parts of the VG. Three are done now - takes about 2 hours to fettle and fit each one, to get it working to mysatisfaction without any binding. So about one an evening. photos to follow when done. P Link to post Share on other sites More sharing options...
Giles Posted February 1, 2018 Share Posted February 1, 2018 (edited) Does this help? You can see the internal link running forward, and the lifting links. The link on the cradle unit is pivoted on the right hand side of the pivot block, just off of the centre line, so far as I can tell. Screenshot_20180127-090018 by giles favell, on Flickr Edited February 1, 2018 by Giles 1 Link to post Share on other sites More sharing options...
PhilMortimer Posted February 2, 2018 Author Share Posted February 2, 2018 (edited) Thanks Giles - most interesting. So it looks like there are no compensators in the reversing mechanism at the pivot points. That said, if the rods are close to the pivot point, as Simon said, the relative movement of the 2 units should have negligable influence on the reverser setting. Completed the 4th set of upper VG and valve guide installation last night - this one was a PITA to do for some reason. Just couldn't get it to fit properly without considerable tweaking. So one loco completed for this stage now. Starting on the second one tonight - hope to get all completed over the weekend. Edited February 2, 2018 by PhilMortimer Link to post Share on other sites More sharing options...
Giles Posted February 3, 2018 Share Posted February 3, 2018 (edited) This is the corresponding plan view, which isn't as informative as it might be - yhough there are some small clues.... Garratt by giles favell, on Flickr Looking further, this is the Hind Engine pivot, and there appear to be bearings either side of centre within the pivot - suggesting that the crank may well be on the centre-line. Hind Engine pivot by giles favell, on Flickr Edited February 3, 2018 by Giles Link to post Share on other sites More sharing options...
PhilMortimer Posted February 6, 2018 Author Share Posted February 6, 2018 (edited) Not a lot to show but an awful lot of time-consuming work. The upper parts of all 8 sets of VG are now fitted and working smoothly. I can push both loco's along and everything waggles correctly and freely. The valve guides have been soldered into position and cleaned up, using the radius rod is temporarily pinned into position in the mid-gear position. The valve rod oscilates smoothly as it should, basically 180 degrees out of phase with the oscilation of the piston rod. At this point, this is correct, as the 90 degree offset comes from the oscilation of the expansion link and excentric rod, which aren't yet fitted. The point of building things up in this manner is to ensure that the valve rod moves smoothly and that there are no binds. Each set of VG was assembled, fettled and checked for smooth operation before moving onto the next one. And there were eight sets to do! I think there was about 8 or 9 full evenings work here to do the complete set. This was aided by my beloved being out in California for the past 10 days, so fewer distractions. Things to note - I had to slightly sand back the valve guide castings so that the top of the combination lever did not ram hard up against it and bind This was further improved by countersinking the the outer end of the valve guide where the valve rod enters. The changes should not be that noticable, espescially once painted up. Also, since the spigot for the valve guide was much smaller than hole in the back of the cylinder, careful position was required using the part assembled VG to aid positioning. So here are the photos. . by Phil Mortimer, on Flickr VG with piston rod at the full forward extremity of the piston stroke - Valve rod fully back. Combination lever clears crosshead and small end bolt. . by Phil Mortimer, on Flickr Piston rod in mid stroke, as is the valve rod. . by Phil Mortimer, on Flickr Piston rod at full rear extremity of the stroke, valve rod fully forward. No binding was experienced in the VG once completed and all power units roll along happily with everything rotating and oscilating as it should when gently pushed. Note radius rod temporarily pinned in mid-gear position with copper wire Finally, a picture of the assembly line. . by Phil Mortimer, on Flickr The next stage is to complete and fit the rest of the VG. But I might give it a few days break and do something else (tanks and bunker?) - my head hurts! Edited February 6, 2018 by PhilMortimer 3 Link to post Share on other sites More sharing options...
Giles Posted February 6, 2018 Share Posted February 6, 2018 (edited) Yes - but a pair of them does make for a lovely line-up! Excellent stuff! Edited February 6, 2018 by Giles Link to post Share on other sites More sharing options...
PhilMortimer Posted February 12, 2018 Author Share Posted February 12, 2018 (edited) I didn't get as much done over the weekend as I'd hoped, even with the atrocious weather preventing any out door work. The eccentric rods were attached to the expansion link to make a sub-assembly. As with the rest of the valve gear, the joint was properly forked using a brass pin soldered on both sides of the fork. This resulted in eight sub-assemblies as shown below. . by Phil Mortimer, on Flickr Its interesting to think that each of these sub-assemblies consists of eleven separate components. (Two eccentric rod laminations, two expansion link laminations, four spacers (two on each side of the expansion link) two expansion link brackets and one brass pin). And there are eight complete sets! I now need to make up the return cranks, then combine the whole lot with the previously installed parts of the valve gear on the power units. And make it all work! Edited February 12, 2018 by PhilMortimer Link to post Share on other sites More sharing options...
PhilMortimer Posted February 12, 2018 Author Share Posted February 12, 2018 Started to laminate up the resturn cranks when I ran into one of the irritating things about this kit. The hole for the pin which attaches the eccentric rod to the return crank is way too big for any normal size pin and much bigger than the corresponding hole for the pin on the eccentric rod. Yes, I can bush it down to the correct size, but that adds time and complexity to the build. Grrr....... Just when you think you are getting somewhere! Link to post Share on other sites More sharing options...
Giles Posted February 12, 2018 Share Posted February 12, 2018 (edited) Absolutely - a bit of a pain.... I used a BA bolt, silver soldered in, which was then trimmed off, and a nut used to secure the rod. Edited February 12, 2018 by Giles Link to post Share on other sites More sharing options...
PhilMortimer Posted February 12, 2018 Author Share Posted February 12, 2018 Yes. One plan is to solder in a 12BA bolt (which has a clearance fot) and use that as the pin. It's just that 12BA seems somewhat large - 14BA is what I have used for everything else. Not a showstopper, but annoying. At least with a bolted connection, I can undo things to remove the wheels..... Link to post Share on other sites More sharing options...
PhilMortimer Posted February 14, 2018 Author Share Posted February 14, 2018 Return cranks laminated up and 12BA pins fitted. Need cutting down and filling back, but should work OK. Just need to fit them onto the crankpin bushes in the correct orientation now. 2 Link to post Share on other sites More sharing options...
PhilMortimer Posted February 16, 2018 Author Share Posted February 16, 2018 Return cranks finished last night - they "just" need soldering to the crankpin bushes. This might be a more fraught exercise than the phrase describes, as I need to ensure that everything is correctly positioned prior to final soldering and there is no positive centre point on the crank to use for alignment. That said, I think I have a fairly good ide how to achieve this. Watch this space....... Link to post Share on other sites More sharing options...
PhilMortimer Posted February 19, 2018 Author Share Posted February 19, 2018 (edited) One return crank fitted, but then got really ill over the weekend which stopped further work (migrane brought on by wrenching my shoulder whilst shifting large round hay bales). Hope to get the rest done over the next couple of evenings, as i have to leave for Montana at the end of the week. Edited February 19, 2018 by PhilMortimer Link to post Share on other sites More sharing options...
Giles Posted February 19, 2018 Share Posted February 19, 2018 Very sorry to hear about that.... as one who all too regularly suffers from migraines (quite well controlled with medication for the last few years) I sympathise greatly. Most debilitating for you. I hope you're recovering, and don't roll over into another one. Link to post Share on other sites More sharing options...
PhilMortimer Posted February 19, 2018 Author Share Posted February 19, 2018 Thanks, Yes back at work today, though that is likely that will bring on another headache! Link to post Share on other sites More sharing options...
ERIC MITCHELL Posted February 20, 2018 Share Posted February 20, 2018 Phil, Simon and Giles , I'm just getting back into the hoppy having stopped due to work etc , i purchased this kit off Jim Harris back in the 90's . Well back in November i started to build the garret, In my quest for photos etc i came on to your post for said garret. Phil and Giles a great THANK YOU, you are saving me a lot of work (or should i say I have now found i have got a lot more work to do than I first thought ) like you Phil I'm committed myself to building 2 (but not like you I'm doing 1 at a time ) lathe out of moth balls plus i have got me a small milling machine ( Proxxon ) i have got both units built and wheels temp fitted took me days to get wheels set now order jig for future quartering !! . 2 Link to post Share on other sites More sharing options...
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