JonL
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WWSME (Wiltshire)
Posts: 2,990
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Post by JonL on Mar 8, 2019 21:19:56 GMT
Thanks Don, I think you are almost certainly right. They are indeed gunmetal.
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Post by David on Mar 9, 2019 0:55:03 GMT
How many 1000s of miles are you planning on driving it?
I don't think anyone down here uses anything other than mild steel for slidebars, with no hardening. Usually cast iron for the crossheads, no slippers until the wear gets too much I'm guessing. We do stretch to hardened silver steel for the con rod little end pins though so new bronze bushes are occasionally required.
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JonL
Elder Statesman
WWSME (Wiltshire)
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Post by JonL on Mar 9, 2019 18:12:15 GMT
 Finished off the crosshead, only thing left to do is the retaining pin to the piston rod, which is what I'll do next. I had held off on doing that in case any dimensions need tweaking. Obviously most of the finishing on this was hand filing. Another therapeutic afternoon. Sorry this picture isn't very different from the last ones... |
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JonL
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WWSME (Wiltshire)
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Post by JonL on Mar 10, 2019 19:14:04 GMT
 Slight deviation from the correct order, before I make the piston rods I wanted to check I had the rest of the dimensions correct, so I jumped ahead and made the connecting rods. Basic bronze bushing at each end, I deviated from the plans and made them a top hat section rather than parallel to make the alignment easier. The photo above is just of everything roughly assembled to see if I've made any major errors. Although I haven't made the rest of the crosshead arrangement for the left hand side yet I went ahead and mae the connecting rods as a pair as it made sense. I usually do this, but the crossheads are complicated enough that I want to do them one at a time (and only make an error once rather than twice before I notice!). |
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JonL
Elder Statesman
WWSME (Wiltshire)
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Post by JonL on Mar 14, 2019 21:01:22 GMT
 Not much time spare tonight (had a few things to finish off to hopefully get my Fiancee's car to pass it's MoT...) but I managed to make up one of the crosshead pins. Slowly but surely it comes to pass.... |
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stevep
Elder Statesman
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Post by stevep on Mar 15, 2019 9:35:18 GMT
That seems a very coarse thread, Nobby. What size is it?
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JonL
Elder Statesman
WWSME (Wiltshire)
Posts: 2,990
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Post by JonL on Mar 15, 2019 9:50:03 GMT
That seems a very coarse thread, Nobby. What size is it? It's 5BA; thats the one LBSC calls up on the drawing, maybe its because its fresh from the die that it looks a bit rough and ready? |
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Post by simplyloco on Mar 15, 2019 13:42:25 GMT
Hi Jon A little bit of history for you: first run of the Britannia! Take particular note at 2.00 minutes where the worker is standing between two driving wheels that are being balanced! John www.youtube.com/watch?v=WTXtLUZ_AO4 |
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JonL
Elder Statesman
WWSME (Wiltshire)
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Post by JonL on Mar 15, 2019 14:05:44 GMT
Blimey, health and safety would have a field day!
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barlowworks
Statesman
Now finished my other projects, Britannia here I come
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Post by barlowworks on Mar 15, 2019 14:31:23 GMT
The worrying thing is I couldn't see anything wrong with that.
Mike
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JonL
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WWSME (Wiltshire)
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Post by JonL on Mar 17, 2019 19:34:13 GMT
Tonight I got the right hand guide bars mounted on their bracket and clamped in the place I'm hoping they should end up! Out of interest I moved the piston valve to the correct point to allow air into one side of the cylinder, applied a few PSI to the inlet and she did a 180 degree spin of the wheels and shot up the piece of track she lives on. So for the first time she moved by pressure alone! I know there is a lot to do but its a great little milestone. Gives me confidence that actually I might just be able to do this. A good little boost.  |
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Post by ettingtonliam on Mar 20, 2019 0:43:20 GMT
The worrying thing is I couldn't see anything wrong with that. Mike Me neither. I think hes standing on front of the balancing machine, much as you stand in front of a lathe, not actually between the wheels. |
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JonL
Elder Statesman
WWSME (Wiltshire)
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Post by JonL on Mar 20, 2019 20:10:12 GMT
Installed LHS Guide Bar Bracket properly tonight, I was waiting on the correct size screws. Just started machining the RHS crosshead, and as expected I've come up with a couple of neater ways of achieving what I did last time (for example cross drilling for the various bolts was measured using the micrometer dials on the lathe rather than engineers blue and a scriber... although I did use a second measuring technique to ensure I got things correct). I suspect my locomotive will have a prettier side as the second component I make in each batch incorporates lessons learned from the first one!
Not huge progress, but gentle pleasant time spent in the workshop. Quite content.
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JonL
Elder Statesman
WWSME (Wiltshire)
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Post by JonL on Mar 21, 2019 12:36:56 GMT
I forgot to mention yesterday, this locomotive has really started to pick up some weight! You insidiously add a component here and a component there and later you try to pick it up and it's turned into a bit of a lump...
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JonL
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WWSME (Wiltshire)
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Post by JonL on Mar 25, 2019 20:54:27 GMT
  Tonight I did the machining on the other crosshead, learning a few things from the last one. As is always seems to be the case with my work the second one was quicker to make and has come out with tighter tolerances than the first...  The picture of them both together shows it before it is hand finished with a file. I'll do that later in the week, it's time to stop whilst the going is good. |
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JonL
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WWSME (Wiltshire)
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Post by JonL on Mar 27, 2019 21:20:20 GMT
 We now have a pair. Almost twins, but not quite... to be fair to myself I've got it quite close, but will do a little more hand filing so they match. I've just noticed that in this picture the part that attaches to the piston rod looks very different sizes on each, I think thats a trick of the light as they but up to each other with only a tiny difference noticeable.  More crucially, its a good fit in the guide bars with nice tolerances and motion throughout. |
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uuu
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your message here...
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Post by uuu on Mar 28, 2019 7:06:11 GMT
You'll never see them at the same time when they're fitted.
Wilf
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JonL
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WWSME (Wiltshire)
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Post by JonL on Mar 28, 2019 7:21:13 GMT
You'll never see them at the same time when they're fitted. Wilf
Very good point wilf. It's something I told myself repeatedly when I was having the issues with machining the cylinder castings. But I want to at least try to get them vaguely similar! :-)
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Post by Jim on Mar 28, 2019 21:57:34 GMT
Like your new avatar Nobby...far less alarming for old blokes like me.  |
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The picture of them both together shows it before it is hand finished with a file. I'll do that later in the week, it's time to stop whilst the going is good.
