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| NickG:
Stew, I guess you could do this either way. If doing it Bogs way you will need a method of setting the eccentrics in relation to the cranks. I was just thinking and I think you could do this between centres in the lathe using gravity to let the eccentric fall to it's extreme downward position before locking up. This would only work if the sheaves are a nice sliding fit on the shaft. Obviously you'd need to work out where to position the crank for each eccentric. For no. 1 (right hand) you would need the right hand crank at back dead centre, since the eccentric is meant to be extreme upward position at forward dead centre. Let the sheave swing down and tighten. No 2. you would need the crank at forward dead centre, let the eccentric sheave swing down and tighten. No. 3. You need the right hand crank to be pointing down (sorry can't remember where the left hand crank sits in relation to the right one). so rotate clockwise 90 degrees looking from right hand end. Let eccentric sheave no 3 swing down and tighten. No. 4 rotate crank 180 degrees, let sheave 4 swing down and tighten. If your eccentric sheaves aren't a loose sliding fit, this won't work, there must be a better method. Of course you could set a clock gauge up on each 1 and turn until it reaches it's extreme position. Once you're happy they are all set in the right positions, you should in theory be able to put the straps on and time it up the way Bogs said again making sure the crank and reverser are in the right positions as per the other instructions but this time moving the valve on it's spindle to attain the hairline crack. I think moving the eccentrics gives you more scope for adjustment though enabling you to optimise the timing both in forward and reverse directions. Give it a go, it might work better or be more obvious what you are doing. Any method that avoids messing about with those eccentrics must be good! Nick |
| sbwhart:
Hi Chaps Thanks for your help and advice its sounds like I'm not a hundred miles off, what I've been doing is lining the eccentrics clamp hole up with the holes that take the web pins they are both on the centre line, bringing the crank on forward dead centre, at this point It all goes to cock because I don't understand the function of the slide valve spindle, that and eccentrics slip :bang: I'm away fro a few days so I'll give it a go when I get back. Cheers Stew |
| CrewCab:
Have a good time Stew and you never know, that "Eureka" moment might just creep up on you :beer: CC |
| arnoldb:
Stew, this is a great build and ever so well documented! :clap: :clap: Had to read it start-to-finish - quite an eye-opener :smart: Have a nice trip :wave: Arnold |
| sbwhart:
Hi Chaps I bet you'd thought I'd given up on this, old Stew's not beaten that easily. Well I did a fair bit of fettling when I got back from being away, sorted out a few areas of binding the main one was from the lifting link hitting the motion frame when it was in the forward position. But still couldn't get it set, I had a few ideas what further fettling was required, but by this time I was losing faith in my own understanding of the system, so took it around to John's for him to have a look at. John patiently explained how to set the valves, I was pleased to here it was how I'd been doing it, John turned things over measured and checked everything seemed to work but things were still fouling on the steam chest, in half an hour John came up with the same fettling ideas that it had taken me two weeks to figure out. Johns help was greatly appreciated. This morning I modified the the steam chest as John suggested but still couldn't get the timing right, but Johns tutorial and watching his methodoligy gave me the confidence that I was going through the correct process, so I started to look at thing afresh. And found that I've assembled the excentric straps wrong :bang: :bang: :bang: :bang: :bang: they should be:- Forward strap, Reverse strap, Reverse strap, Forward Strap. what I've done is:- Forward strap, Reverse strap, Forward strap, Reverse strap, No wonder I was struggling, the bloody thing was going when it should have been coming and coming when it should have been going: :hammer: :hammer: :hammer: :hammer: :hammer: :hammer: :hammer: :hammer: :hammer: I've got to strip the linkage down and assembly correctly, which is a job for tomorrow, so keep watching this space. Not yet beaten Stew |
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