Simond Posted January 9, 2017 Share Posted January 9, 2017 Phil "One thing that I need to work out is if the wheels can be removed with the slidebars fitted" My guess is that unless you can get the crossheads out, you won't be able to undo the csk wheel bolt, and if you can't do that, you can't separate wheel & axle, and if you don't have hornblocks with removable keepers allowing them to drop out below, the answer is going to be "no". If you can solder the motion brackets and cylinder formers to some kind of dummy frame, so it separates from the real frames... no, I thought not! This is probably not an opinion that you wanted, sorry. Simon Link to post Share on other sites More sharing options...
PhilMortimer Posted January 9, 2017 Author Share Posted January 9, 2017 Simon, Probabaly not, but it's the answer i expected! I think I'll just have to make up the slidebars and see how everything fits. At heart, I'm an experimentalist (aka tinkerer), so it will be interesting to see what the outcome is! Link to post Share on other sites More sharing options...
Simond Posted January 9, 2017 Share Posted January 9, 2017 Hornblocks... Link to post Share on other sites More sharing options...
Guest Isambarduk Posted January 9, 2017 Share Posted January 9, 2017 Hornblocks with keepers are definitely the answer. "you won't be able to undo the csk wheel bolt," That would be the Slater's csk socket head screw! David Link to post Share on other sites More sharing options...
Simond Posted January 9, 2017 Share Posted January 9, 2017 Yes, it would... Link to post Share on other sites More sharing options...
PhilMortimer Posted January 10, 2017 Author Share Posted January 10, 2017 (edited) "Hornblocks with keepers are definitely the answer." Unfortunately not in this particular case. The bearings are in and everything is working and at this stage I just don't feel like taking it all apart to put hornblocks in. However, they are going into the next loco in the build queue, probably with CSB. Indeed, I already have them here awaiting installation. Edited January 10, 2017 by PhilMortimer Link to post Share on other sites More sharing options...
Simond Posted January 10, 2017 Share Posted January 10, 2017 Kind-of had that thought in mind, and I don't think I'd fancy taking a step or two backwards either, but if I were to, I'd leave the rear axle bearings fixed, and use cast brass hornblocks (Fourtracks do a nice example) soldered inside the frames, and using the coupling rods to locate them. Alternatively, can you get the crossheads out of the slide bars at the rear? If so, the SCREW will come out, and as long as you can waggle the wheels off the axle, and as long as the axle will go through the gap between the slidebars, you're in business... Best Simon Link to post Share on other sites More sharing options...
PhilMortimer Posted January 11, 2017 Author Share Posted January 11, 2017 Not sure, but I think so. Basically, I think that I need to make up the slide bar assembly and trial fit them, to see if I can get the wheel to waggle off with them in place. If I can, problem sorted. If not, them plan B, whatever that is. Making up the slide bars is going to be an exercise in ingenuity, as I have to work out how to do several manufacturing operations first (without machine tools), such as drilling out the glands in the cylinder ends to accept the piston rod, drilling out the cross head to accept a new N/S rod to form the piston rod (rather than the integrally cast one) and fabricating the sidebars. Whilst this is all simple in principle, marking everything out and ensuring that all the parts are setup properly and drilled square and centered will require some thinking about. That won't happen today, as I've just got back from South Philadelphia (what a grim place!) where I have been stripping a mass spectrometer for useful spare parts that I can use to keep my own instruments working. Am tired and sore and I think my bed looms! Link to post Share on other sites More sharing options...
RMweb Premium Michael Edge Posted January 11, 2017 RMweb Premium Share Posted January 11, 2017 Kind-of had that thought in mind, and I don't think I'd fancy taking a step or two backwards either, but if I were to, I'd leave the rear axle bearings fixed, and use cast brass hornblocks (Fourtracks do a nice example) soldered inside the frames, and using the coupling rods to locate them. Alternatively, can you get the crossheads out of the slide bars at the rear? If so, the SCREW will come out, and as long as you can waggle the wheels off the axle, and as long as the axle will go through the gap between the slidebars, you're in business... Best Simon You will have to make the drop link removable to get the crosshead to come out from the slidebars after assembly. Link to post Share on other sites More sharing options...
Simond Posted January 11, 2017 Share Posted January 11, 2017 Ah, yes, good point, Michael. Sorry, Phil, I tend to live in a Swindon world where such problems are rather rarer. Phil, I'm struggling to see how you use a mass spec for modelling.... Best Simon Link to post Share on other sites More sharing options...
PhilMortimer Posted January 11, 2017 Author Share Posted January 11, 2017 (edited) Simon,I don't. It's the day job...... Though various pieces of mass spec (BA nuts and bolts, etc.) have indeed found themselves being incorporated into the models i build.http://sites.krieger.jhu.edu/mass-spec/Michael.I think the drop link can be made removable if nessecary. I will just have to experiment a bit to see if I need to make it so. Edited January 11, 2017 by PhilMortimer Link to post Share on other sites More sharing options...
Simond Posted January 11, 2017 Share Posted January 11, 2017 Phil That's really quite cool. I come from an Automotive Engineering background. We were introduced to mass spec's in uni days, but I can't recall having used one in anger. The engine, paint, lubrication, and more recently the echem boys & girls would, but I'm a rude mechanical... Best Simon Link to post Share on other sites More sharing options...
PhilMortimer Posted January 12, 2017 Author Share Posted January 12, 2017 Ah yes, but Mechanical Engineers work out how to build the things in the first place. Ok, back to Garratts. I've now worked out how to hold the cylinder ends for drilling. Need to find my foot switch for the mini-drill though. Link to post Share on other sites More sharing options...
PhilMortimer Posted January 13, 2017 Author Share Posted January 13, 2017 Six of the eight cylinder ends have now been drilled. Just one broken bit. I used a mini drill held in a stand. Not ideal for accuracy (Oh for a mill), but what I had available. Took an age for each one - that brass is HARD. Hope to finish the other two tonight. Link to post Share on other sites More sharing options...
Simond Posted January 13, 2017 Share Posted January 13, 2017 The little Proxxon one isn't bad value, and I understand they're pretty solid. Don't know how easy they are to get in your corner of the world. I guess alternatives exist. http://shop.prox-tech.com/c/bench-top-units-and-related-accessories_micro-mill-mf-70?pkey=418b633f2d7efa03f88cf8c8c33754f4&ckey=1098129.1111315.0.0.0 You probably wouldn't want to use one of these tiddlers for a 5" gauger, but for 7mm, plenty big enough. I bought an age-old Dore Westbury many moons ago, just refurbished it with a variable speed AC drive, seems good. Probably too big for convenience on some work, but whilst you can always use a big hammer gently, the opposite ain't true! That said, I'd get one of these if I didn't have the larger one. (And we've a whopper of a Bridgeport at work if I ever need to do something really heavy) Best Simon Link to post Share on other sites More sharing options...
PhilMortimer Posted January 14, 2017 Author Share Posted January 14, 2017 Thanks Simon, That is worth thinking about. It is available over here and not at a bad price. I know that Proxxon have a reputation as a good brand. I need to think about it and decide if it will be sufficient for my future needs or will I be limiting myself in the future and need to get something a bit larger? Decisions, decisions. Link to post Share on other sites More sharing options...
PhilMortimer Posted January 15, 2017 Author Share Posted January 15, 2017 (edited) The final two cylinder ends have now been drilled out. All are to a diameter of 63-65 thou, which accepts a 1.5 mm dia piece of N/S rod nicely with with a good sliding fit. I have now started to prepare the cross heads to also accept the same size N/S rod as the piston rod, instead of the integrally cast one, which is anything but straight or round. Now this is personal preference, but I personally dislike piston rods cast as part of the crosshead, since the rod never looks right to me and often is badly twisted out of alignment. I prefer to replace it with some hard round rod of the appropriate diameter. It would be easier if the crosshead casting had a dimple in it to aid positioning of the drill, but as this casting already had the cast rod, this wasn't available to me. I have however now developed a method to fairly accurately determine and mark out the center point of the cross head to enable it to be drilled to accept the N/S piston rod. I will try and describe this tomorrow once I have some pictures. In the meantime. I continue to ponder small miling machines. Edited January 15, 2017 by PhilMortimer Link to post Share on other sites More sharing options...
Giles Posted January 15, 2017 Share Posted January 15, 2017 Well worth the investment in some shape or form....! I recently acquired another Garratt which won't see the light of day for a while - nicely made, but unfortunately all to the instructions, which means so much of it is not correct, and will need remaking...... Those b*******y instruction!!! Link to post Share on other sites More sharing options...
PhilMortimer Posted January 16, 2017 Author Share Posted January 16, 2017 (edited) Some further progress. Below is a quick picture of the cylinder ends and glands all drilled out. They are currently slid onto the 1.5mm N/S rod that will form the piston rods for safe keeping. WF_Garratt_118 by Phil Mortimer, on Flickr The crossheads are the next thing to be prepared. As supplied, the piston crossheads have the piston rods cast into them. I never like this because, as can bee seen in the photo below, they are never straight and correctly lined up with the cross head. I prefer to remove the cast rod and replace it with something more appropriate, such as N/S rod (in this case 1.5mm dia). The cast crossheads are seen below on the right as suppplied, together with some modified ones on the left. WF_Garratt_119 by Phil Mortimer, on Flickr To modify the crossheads, the cast rods are removed and the crossheads are drilled centrally through the boss. Personally, as stated above, I prefer crossheads to be supplied without the rods and with a starting dimple cast into them to enable accurate drilling for the rods. However, this was not the case here. After removing the cast rods, the residual nub was filed flat to the surface of the crosshead boss, (where on a real loco, the piston rod is secured to the cross head). The flat boss surface was covered in green marker pen, which was then allowed to dry. WF_Garratt_120 by Phil Mortimer, on Flickr The difficulty here is drilling into the boss centrally, without the drill wandering off. A pilot hole is needed. With machine tools (Still hankering for a mill) and a centre drill, this would probabaly be fairly easy. However, I don't have access to them and just have a small pillar drill (Basically a dremel in a stand, which isn't that rigid). However, I got lucky in that the cast crosshead boss was a tight push fit into some 1/8" ID brass tube. So, this meant that I was able to slip the tube over the boss, then drop an 1/8" drill bit down the inside of the tube, and using the hand powered pillar drill, was able to pilot drill the center of the boss without the drill wandering. I took it slowly, and rotated the tube several times around the boss as I was drilling, to ensure that any deformation of the tube was counteracted. I was suprised how well this all worked - all of the pilot holes were spot on in the centre of the boss (accroding to the Mk1 eyeball!). WF_Garratt_121 by Phil Mortimer, on Flickr WF_Garratt_122 by Phil Mortimer, on Flickr Doing all eight cross heads took a while, as I didn't want to rush this, but I eventually ended up with eight pilot drilled crossheads which are all correctly centered. Wonderful! WF_Garratt_123 by Phil Mortimer, on Flickr Subsequent to this photo, each of the cross heads was mounted squarely and drilled out 1mm diameter, using the stand mounted dremel. This will then be later opened out to a 1.5mm dia push fit of the N/S Rod into the crosshead boss, but it was getting late and I figured that it was time to quit whilst I was ahead. This will be done in the next few days. The N/S rod will be pushed into the finished hole and soldered. Giles used silver solder for his slidebars and valve-gear, but I don't have any. However, I have some 220 degree solder, so may use that with a flame. I had briefly entertained the idea of shrink fitting the rod into the cross head by imersing the various parts in liquid nitrogen (in the same way that cylinder linings are installed in full size loco's), as I have access to LN2 at work and it's fun to play with. However, I decided that the risk of splitting the cross head boss was too high as the rod expanded as it warmed up to ambient temperature. So it will be soldered instead. Still, it would have been fun to do! Edited July 2, 2017 by PhilMortimer 2 Link to post Share on other sites More sharing options...
Guest Isambarduk Posted January 16, 2017 Share Posted January 16, 2017 I hope that your piston rods finish up in the right place for you. My worry with your jig is that, although it lines the rod up in the centre of the boss, it relies on the boss being cast centrally to the working surfaces of the crosshead. Fingers crossed! David Link to post Share on other sites More sharing options...
PhilMortimer Posted January 17, 2017 Author Share Posted January 17, 2017 (edited) Ah yes, but once I have the rods fitted centrally to the boss, I then have a reference point to make any adjustments to the sliding surfaces so they are equidistant from the rod. I think visually, it needs to have the rod centrally mounted in the boss, otherwise things will look distinctly odd.Actually, a quick check indicates that there are only a few thous discrepancy from the rod to the sliding surfaces, one side to another. That is probably sufficiently good enough for a model. With the exception of the integrally cast piston rods, the crosshead castings are very good and not significanntly assymetrical. Edited January 17, 2017 by PhilMortimer Link to post Share on other sites More sharing options...
PhilMortimer Posted January 17, 2017 Author Share Posted January 17, 2017 (edited) I recently acquired another Garratt which won't see the light of day for a while - nicely made, but unfortunately all to the instructions, which means so much of it is not correct, and will need remaking...... Those b*******y instruction!!! Giles, you are a glutton for punsihment! Did you not get put off by the experience last time? Seriously, if it is well made, is it even worth re-building? Do we get to see pictures? Edited January 17, 2017 by PhilMortimer Link to post Share on other sites More sharing options...
Simond Posted January 17, 2017 Share Posted January 17, 2017 Phil I've posted a picture of a filed tapped tophat bush as a crankpin, and the spanner, on my PD thread. Hope it's helpful Simon Link to post Share on other sites More sharing options...
PhilMortimer Posted January 17, 2017 Author Share Posted January 17, 2017 Many Thanks, I'll take a look Oh, just so you know, its because of you I've spent the last few evenings perusing Bench top Mills and Lathes. Diane says you have a lot to answer for, but she thinks its a great idea, espescially as we met ina machine shop. Basically, she wants me to get a Mill and Lathe so SHE can play........ 2 Link to post Share on other sites More sharing options...
Simond Posted January 17, 2017 Share Posted January 17, 2017 Job done.... An understanding and cooperative wife is a joy forever! Many moons ago, I was running my 16mm live steam Prince and some coaches around a local club outdoor track. One of the other members asked me a question, and as I was having difficulty gesticulating (I'm an engineer, remember, tie my hands and I'm dumb) and driving the train, MrsD took over. A few minutes later another chap asked if that was my train, and my wife. I acknowledged that this was indeed the case. "Lucky b*****d!", was the only reply... Best Simon Link to post Share on other sites More sharing options...
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