Sorting out the accumulated part done and not yet started things workbench

Discussion in 'Workbenches, including workshop techniques.' started by Martin Shaw, 28 March 2020.

  1. simond

    simond Western Thunderer

    Martin,

    I know you didn’t like the original bearings, but wouldn’t it have been easier to attach a bush into a hole in a suitable plate, silver solder perhaps?

    You do seem to have rather less metal than you started with...

    (I’m not mean, I’m just careful... :) )

    Atb
    Simon
     
  2. Martin Shaw

    Martin Shaw Western Thunderer

    Simon
    I'm not in any doubt that this is perhaps more wasteful of raw material but you will remember from photos of where I started that there are an awful lot of joints, both mechanically fixed and soldered and a part of the exercise is to try and improve some of the design, whether it will be successful is undoubtedly questionable. As it is I think this arrangement will only work on one end of the bogie and the other end will be a bearing soldered into a plate, but I want to try this out first. I certainly don't like wasting material but the counter to that is sometimes a spend may expedite things, and in the scheme of things I suppose I've "wasted" a couple of quids worth, so be it. As for easier, certainly on paper.
    Regards
    Martin
     
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  3. Martin Shaw

    Martin Shaw Western Thunderer

    Not much to show today, bits have arrived so a tryout of the layshaft seemed a good idea,
    IMG_0973.JPG
    the problem is that the bogie frame is far from square and bits of it aren't vertical so when clamped up the bearings are pulled out of line and the shaft tightens up. I think one end will require something adjustable in horizontal and vertical planes, not too dissimilar to what was there in the first place, although to be fair to myself I did recognise his might be an issue. One of the bearings can go into the A end bogie. I also started on new motor mounting brackets
    IMG_0975.JPG

    the motor fitted to the new bracket, I can only fit one screw, someone in the past has done something to the other one that has no roots in engineeering, the scrofulous old bracket is for comparison.

    Martin
     
  4. Martin Shaw

    Martin Shaw Western Thunderer

    No pics cos there's nothing new to see, however I have sorted the problems. The tightness wasn't as I thought due to alignment, one bearing had a highspot which when removed allowed everything to turn sweetly with a tad of adjustment. I found the pinion shaft was also bent, unfortunately I made it's replacement about 1mm short and when loctited into the drive coupling too far had insufficient length to lock the pinion on, so I'll have to do that bit again. It does all work though and considerably better than where I started so I suppose a positive result. I should before considering it finished fit some pickup, I said at the beginning of this section "I decided on something relatively easy, at least at first appearance", I really should have known better by now.
    Regards
    Martin
     
  5. Martin Shaw

    Martin Shaw Western Thunderer

    So there I was quite happily making the second motor mounting bracket, it was all going swimmingly well and not a care to be had, when I got to this stage and thought to check it against the motor,
    IMG_0976.JPG
    where to my great annoyance I disproved my assumption that Messrs Buehler used the same size boss at both ends of their motors. In contrast to the first one that is 12mm in diameter, this end only needs a 10mm one. I'll have to do it again, this one can join its compatriots in the box marked useful bits that seems to have been accumulating things for the last 25 years, none of which has ever shown any signs of being used.

    Kind regards
    Martin
     
  6. Steph Dale

    Steph Dale Western Thunderer

    Hehe, so you also have a 'solutions awaiting a problem' box...

    Steph
     
  7. Overseer

    Overseer Western Thunderer

    You are more of a perfectionist than I am. Maybe I am just lazy but I would have made a 1mm 'washer' and soldered it in place, or being really lazy a ring of 1mm wire (square or round) would be even quicker.

    I have been meaning to ask about the side and end thrust of the helical gears. I have only ever used them in a gearbox where they are constrained. Would they cause more wear in the bearings or flex in the shafts than worm and wheel gear sets?
     
  8. Brian McKenzie

    Brian McKenzie Western Thunderer

    A suggestion to reduce the end thrust loading imposed by those three sets of helical gears might be to trap a steel ball inside the end of [redesigned] bearings for the longitudinal shaft. This worked extremely well for the Triang motor bogie of old.

    This would involve reworking some of what you have already made, but would ease the loading on the motor, and perhaps provide for smoother starts (without the boss of the helical gears needing to rub against the shaft bearing).

    Martin Shaw bogie mechanism_0973A.jpg
     
  9. Martin Shaw

    Martin Shaw Western Thunderer

    Well I don't know about perfectionist since it's all but impossible to achieve, but in fairness I do like it to be right. Because of where I photographed it, it looks like brass but is in fact ali. I could turn a 1mm ring and epoxy it in, I'll sleep on that.

    I'm far from an expert on gears, but if I hadn't had to dismantle it all to put the new wheels in I doubt I would have done anything mechanical to it, it's very much overengineered for any requirements I would have, it's original use dictated the way it was made. Beyond that helical gears are more efficient than worm and wheels and thus more motor power ends up at the road wheels I've no great understanding of the technical benefits and deficiencies of one versus the other. I've no doubt the internet could answer this but even now life is too short.

    Brian
    Thanks for that piece of info, as I have got this far I'm inclined to finish it as is and see whether further works might be justified. The way the motor is connected to the pinion shafts via sliding dog clutches eliminates end thrust on the motor bearings, and the gear ratio is fairly low anyway so it shouldn't be an issue. I am pondering whether to reinstate flywheels. I have to use what I have, which does include another complete set of gears, I can't but think that a set of these would be rather expensive.
    Regards
    Martin
     
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  10. Martin Shaw

    Martin Shaw Western Thunderer

    Well in the end I decided to redo it, the first version can go in the spares box.
    IMG_0977.JPG
    A pleasant afternoon with Johnnie Walker on the radio. The small notches in the sides are to clear the folded clips that hold the brush gear in the motor end cap and I assume are live, there you go me making assumptions again. This is the final product,
    IMG_0978.JPG
    I am, modestly of course, rather pleased with how this has turned out, certainly better than what was there before. I have also realised that if I reverse the mounting angles on the solebars the motor shaft ends up at more or less the bogie pinions shaft height which should be a bit less power consumed in making it all go. I think the second bogie is next then I can look at flywheels.

    Best wishes
    Martin
     
  11. Martin Shaw

    Martin Shaw Western Thunderer

    After yesterdays beneficial exercise it seemed logical to finish the whole motor arrangement in the frames. A previous pic shows two brass angles soldered inside the frames, spaced with a plate across the width, with the motor brackets all bolted together. Sans motor it was all a bit flimsy, when all is said and done the frames are only ns channel joined at the headstocks, so I made up two crossmembers to space and hold the frames together which would also allow the motor to be mounted,
    IMG_0979.JPG

    cutting out the recesses in situ was a pain and in the end it took 4 goes to get it all soldered in the right place, such is life sometimes. As can be seen the middle step has suffered excess heat as did the other side, they have now been reattatched. Fitting the motor was a simple exercise but I fixed the screws into tapped holes rather than using nuts on the underside, less for the arthritic fingers to hold.

    IMG_0981.JPG
    I've also discovered tonight a bit of a cock up. The axles are spaced from the side frames by brass collars that are just a bit bigger than the insulating bush in the wheel centre, so my careful work to make it 2 rail is thus far not further on, it is still a dead short across the running rails. The plan is to turn some PTFE top hat bushes that will fit in the side frames and also take up the end float of the axle. It's not ideal and they will wear out, but replacing them will be someone else's problem. The real downside is that the bogie will have to be dismantled almost completely which is a pain since it appears to be working quite well, I suppose it could be worse, both bogies might have been at the nearly finished stage, 2 steps forward and perhaps only half a one backwards. Whilst the PTFE is on order I can turn the new flywheels.

    Best wishes
    Martin
     
  12. Martin Shaw

    Martin Shaw Western Thunderer

    I have been having trouble with an eye, which thankfully has been sorted so not too much has been done. An attempt was made at flywheels that didn't go well, somewhere along the line I got the order wrong and eccentricity (more than normal) crept in. I think I've got a get around involving plugging the centres and redrilling, using a collet to hold the boss rather than the 3 jaw chuck, worth trying anyway. The PTFE arrive last Friday so at the weekend I took the bogie apart again, This needed the blow torch and inevitably bits I didn't want to move, did, so I realised that the whole thing had to be dismantleable without invoking heat. The first thing was to sort out a main frame spacer that could have the frames screwed to it. I didn't have a suitable piece of stock to mill whole so it involved cutting rebates and soldering uopstands in place that were then drilled and tapped, thus far so good.
    IMG_0982.JPG
    The main cradle is fixed either side by one screw and soldered to remain in place and this needs changed and I then thought the whole frame is hardly square and whilst the earlier bogie end arrangements kept it all in place, it would be a challenge every time it was taken apart. It all really rather means that complete new bogies with all the requirements designed in at the outset would be the logical way forward, but it is alot of additional work, so while I ponder this and possibly do the design work, all the bits have been returned to the box for safe keeping. Meanwhile some items of railwayana are getting refurbished prior to going for auction, keeps me busy anyway, more in due course.
    Kind regards
    Martin
     
  13. Martin Shaw

    Martin Shaw Western Thunderer

    Well that's another week passed since the last post, seems much the same as the last 28. I have been plugging on with railway bits refurbishment, a lot has been done and I'm close to reassembly of some of it, a pic or two when they're done. I made a start on designing new bogies for 20003, it became apparent that the gear meshing centre dimensions would be critical so I had a look online, and wished I hadn't. The spur gears are easy enough and I have established that they are 0.6 mod at 19.0mm centres. The helical gears are much more complex, and the formulae for calculations looked too difficult, lots of Cos lambda functions and stuff I forgot 50 years ago where I intend it should remain. So I went down the empirical route,
    IMG_0994.JPG
    I hadn't got any channel so two bits of angle were screwed together and squared up which also gave a useful width just under the overall width of a block which had a rebate cut in it so that the channel was a running fit. The block had a hole to suit the layshaft centred on the axle gear and the channel had a slot cut in the bottom to allow adjustment and the axle and gear fitted. By sliding the channel in the block the mesh can be adjusted, which was done with a tad of backlash, and then the shaft centres measured, which came out at 11.00mm, maybe a smidge under. The best online help came in at 10.8, so I've settled on 10.9mm as a design figure, there will have to be some adjustment in the layshaft bearings anyway but it does mean that the mesh of the spur gears shouldn't be too much affected by any adjustment neeed for the helical gears. This is all perhaps a lengthy way of saying I'm winging it backed up with a bit of dubious engineering, far more prominent engineers than I have done this, most of them got away with it, hope I will too.

    Best wishes
    Martin
     
  14. Martin Shaw

    Martin Shaw Western Thunderer

    This is where I am, doesn't look a lot does it. I make no claims whatsoever in being a CAD expert, largely self taught if I'm honest so I probably don't maximise the programmes potential fully, but I can get close to where I need. I have a little leeway in the overall length but not much, constrained as I am by the decorative outer frames. The end to sides fixing is taxing thoughts, I think ends milled from solid might be the answer, except there are four of them, set against making all sorts of brackets that should really be silver soldered, it's a bit of work either way. The drawing is a bit confusing because most of the hidden lines aren't but the black outlines are frames and mountings, the blue gears, there are further coloured bits to add. I've had enough today though.

    Best wishes
    Martin
    20003 inner bogie.JPG
     
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  15. Martin Shaw

    Martin Shaw Western Thunderer

    It's moved forward a bit and in reality I don't need to draw this up much further, I can dimension the major parts to allow them to be manufactured and the smaller bits made to fit. I'll probably doodle around with it a bit longer, I fine it suitably distracting cos I don't have to concentrate too hard, the mistakes are easily corrected when it's just 0s and 1s. This is a jpg file and it uploads ok.
    Regards
    Martin
    20003 inner bogie 2.JPG
     
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  16. Martin Shaw

    Martin Shaw Western Thunderer

    From the general arrangement drawing I have extricated the relevant parts to produce dimensioned manufacturing drawings of the frame sides and stretchers,
    20003 inner bogie frame sides.JPG
    20003 inner bogie frame stretchers.JPG

    I need four of each, the side frames can all be milled together and it was the plan to start this tomorrow, unfortunately I only have 1" wide stock which is too high a wastage rate so I'll order some 3/4" tomorrow, might be able to start this on Wed/Thurs. The stretchers will have to be done individually and they are a bit of an accuracy challenge but as long as I concentrate and set it up properly the DRO should take care of things. There is no doubt that a half decent pencil sketch would have done just as well, it is a one off exercise, but I quite enjoy drawing and it gives the impression that I know what I'm doing.
    Best wishes
    Martin
     
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  17. Martin Shaw

    Martin Shaw Western Thunderer

    I was very practical today, and since I was unable to start the sides it made sense to do the stretchers. I sawed off 4 pieces a tad over length from a 1/2" by 1/4" flat bar, squared off the ends and cut the rebates for the frame sides at either end, only two here for reasons explained later
    IMG_1007.JPG
    Each one is clamped down by the rebates to the table of the mill and the excess material removed. I'll put my hand up here, the first one was a bit ragged, firstly the milling cutter which I realise was one of the first ones bought in 2017 was blunt, and I made a fairly fundamental cock up in reading my own drawing and got one of the centres out from it's intended position so I cut my losses there and launched it. A new cutter worked better and after getting that bit right the holes were drilled and tapped. It's a bit of a laborious process, but other than fabrication which would be a different kind of pain this still seems the logical way to do this. I ended up with a finished one,
    IMG_1005.JPG
    The finish is a bit heyho as can be seen, either too many or not enough revs, but it's dimensionally accurate and will do the job, so one done, one in the bin and two blanks ready to go. Quite a good day really.
    Best wishes
    Martin
     
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  18. Martin Shaw

    Martin Shaw Western Thunderer

    I was idly sitting in the workshop when I took a closer than usual look at the Velux windows, the two south facing ones have 30 odd year old blinds that had reached a point of decrepitude, the woodwork was in need of some sanding and varnish and the operating mechanisms were in dire need of lubrication. New blinds are going to be ordered tomorrow, that's Nov spending money away, and one window has been done with much improvement, it's all for the greater good I suppose.

    In between times I've had another go at flywheels, the first attempts were scrapped, they needed too much effort so stock from the store was sawn for blanks, and this time I thought about the sequence of operations. Face both ends, turn a 10mm dia boss, rechuck in a collet for maximum concentricity, skim the outer surface and lastly bore to size. This seems to have worked in that they rotate concentrically on the motor with no shoogling about, they still need grub screws fitted and final length to be determined when more bits are set up for a trial, but I have moved forward a bit. Necessary trip to the dentist early doors, needs must.
    Regards
    Martin
    IMG_1019.JPG
     
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  19. Martin Shaw

    Martin Shaw Western Thunderer

    Thankfully the dentist wasn't painful so more progress today, the frame stretchers are complete, hooray.
    IMG_1022.JPG
    You'll notice a subtle variation, I realised that I was milling the middle ribs to a size that I didn't need to hence two are wider. This also arrived today, should be some help,
    IMG_1027.JPG
    Regards
    Martin
     
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  20. oldravendale

    oldravendale Western Thunderer

    Martin.

    Out of little more than offering another view of 20003 here it is in Eastleigh Works on 23rd May 1965. Actually two views, one from a Kodachrome slide and the other from Kodacolor negative. 34098 behind, 73016 to the right with the red primed smokebox door.

    RV44.  Eastleigh 23 May 65. Co-Co 20003 with 34098 in works..jpg 20003.  Eastleigh Works.  23 May 1965.  Personal Collection.  Final.  Photo Brian Dale.jpg

    Brian