uuu
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Post by uuu on Dec 14, 2023 17:49:19 GMT
Could you fix the buffer stocks with a central spigot and big nut - ensuring they're nice and strong for when people try to lift the loco by its buffers? Then the 6BA and 8BA fasteners can be just cosmetic and threaded into the buffer stocks only.
Which is another way of saying I've no idea how to drill the small holes.
Wilf
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Post by uuu on Dec 9, 2023 17:27:39 GMT
You need to cut down the number of variables here. Ideally you should test the injector on someone else's loco with compatible pipework. If it works, then your pipework is to blame, if it doesn't then you can start to play with the injector itself. And/or - borrow a known good injector and try it on your setup.
Wilf
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uuu
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Post by uuu on Dec 7, 2023 11:31:22 GMT
I don't expect the designer went through much heavy thinking:
How many rings shall I fit? One would be too few, three seems like overkill - two it is then.
How big? Well, the makers will have a Myford, and a ruler. So 1/8" wide ought to be do-able. Nice round number. And, say, 1/16" thick.
Does this work in practice - it seems to - so Tada!
Then it takes a more cerebral person to come along (Prof. Chaddock) to add a bit more analysis, and conclude that in most designs the rings are too stiff.
Wilf
Most of us don't even trouble to think at all - we just make it according to the drawings. A few brave souls experiment with alternative materials. And Roger ploughs his own furrow, of course.
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uuu
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Post by uuu on Dec 6, 2023 14:45:30 GMT
For an old motorcycle, I'd be looking for a spares supplier, like here: montysclassicmotorcyclesshop.co.uk/pistons-and-piston-rings-30-c.asp. They'll likely do them for standard sized pistons, and in increments getting larger to suit a re-bored cylinder. They'll also likely have the specialist knowledge to guide you if you're unsure of what you've got. Wilf
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Post by uuu on Dec 4, 2023 18:02:50 GMT
I've not found a dimensioned drawing of one with the steam pipe passing through. LBSC has one in "Shop, Shed and Road" where the oil tank is on a branch to the side - and the hole is marked "Drill No. 80".
Wilf
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uuu
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Post by uuu on Nov 30, 2023 19:49:13 GMT
Or CamBam.
Wilf
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Post by uuu on Nov 30, 2023 14:23:45 GMT
There should not be a huge effort required to move the piston - some effort, obviously, but not huge. Since Clupet rings are used in I.C. engines as well as steam, there may be different requirements - did your manufacturer know they were for a steam model? There's an interesting reference within this web page ( www.jerry-howell.com/PistonRings.html), to work by Prof Chaddock and Tom Walshaw (Tubal Cain) on the excessive wall pressures found in many models. Chaddock suggests 13lbf/sq.in to be appropriate for rail models. Not that it's easy to work out what wall pressure you've got. Wilf
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Post by uuu on Nov 25, 2023 12:33:11 GMT
I use CamBam to generate G-code from the DXF files, from SolidEdge - and it works fine for me. But this is 2D. It does 3D, I believe, but I've not tried that.
It's free to start with - then still free for small jobs (1000 lines of code). I've paid for it, to remove the limitation.
Wilf
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uuu
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Post by uuu on Nov 24, 2023 14:14:40 GMT
OT.
What I've done today... is to moan about Christmas lights. Who thought that having an automatic 6-hour timer on lights was a good idea? I suppose I could have two sets everywhere with one timed to come on when the others go off.
Wilf
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uuu
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Post by uuu on Nov 24, 2023 8:53:09 GMT
Your story contains an interesting point. If a small air leak is sufficient to require the compressor to run almost continuously - how much more effort is required to sustain the jet of air up your chimney?
An IWMES member used this firing method - it was very successful at the loco end - but the club's (quite decent sized) compressor was given a good thrashing.
Wilf
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Post by uuu on Nov 23, 2023 21:56:10 GMT
I have a drawing "PSV#5" modified 5/10/2011 from Polly for 1/4" bore, showing the diameter of the shroud as 0.385", same as you. The ball projection from the shroud shows as 0.093" to 0.100".
Wilf
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Post by uuu on Nov 23, 2023 19:32:36 GMT
You get extra grip on the rails with as as-cast surface. Not to mention improved brakes.
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Post by uuu on Nov 21, 2023 12:03:58 GMT
Looks fine!
Wilf
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Post by uuu on Nov 17, 2023 14:35:09 GMT
My gut feeling is that the pressure gauge will not get as hot as 150-200C. You could try splashing water on it to see if it sizzles. I'm guessing not - but worth the experiment. Then the waterslide transfers etc. may be stable.
Wilf
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Post by uuu on Nov 17, 2023 8:29:27 GMT
Ah yes. A bit of Isle of Wight background. I'll not go back into the Arthur Grimmett injectors days, Julian is better at telling that tale - but my friend John got a reputation for making pumps - hand and axle pumps etc. We were making one this week. So he became John the Pump, to distinguish him from Little John and any other Johns that were around. For many years he's opened his workshop one evening each week for chaps to gather and help each other out. And drink tea - beer afterwards. So the workshop became the Pump House. Simples.
Many fascinating things have been made and mended at the Pump House. Parts for a Spitfire. For the Docklands Light Railway. British Aerospace! Honda! Amazing what you can do with a Myford if you know what you're doing.
There are fewer of us now than in times past. Normally two, but three this week.
Wilf
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Post by uuu on Nov 16, 2023 10:12:47 GMT
Perhaps not quite the mid-point. But what you're wanting is just enough taken off the rectangle so it will swivel within the space within the lathe bed.
If I remember right, my currently-mislaid one was prettier - with a curved cut-off. And with a pocket in the bottom to take the foot of a standard Myford tee-slot bolt, so not threaded. But functionally exactly the same.
Wilf
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Post by uuu on Nov 16, 2023 10:07:58 GMT
OK - here's the plate on the bottom of John's fixed steady: 20231115_190844 by Wilf, on Flickr It starts with a rectangle 1.765" long, 1.250" wide and 0.375" thick. Two corners are truncated from the mid-point of the short side, so the longer edge measures 1.555". The holding bolt is 3/8" BSF, hard screwed to the plate, so you can control its orientation from above. Hope that helps. Wilf
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Post by uuu on Nov 14, 2023 11:06:52 GMT
At the Pump House we've found removing crankpins with an arbour press is effective. A bit of heat helps, but we've never had to get them really hot - the press seems to do the work.
I think we're on the third set of pins for John's loco, (so far).
Wilf
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Post by uuu on Nov 14, 2023 11:00:23 GMT
I was wondering the same thing myself, wanting to make a face for a small clock. So I did a bit of Googling, and came up with this guy, making custom dials for watches: watchcomplications.com/making-custom-dials/His process seems to involve using a laser printer to make a waterslide decal, applying this to a painted surface, baking in the oven, then applying an acrylic coat. I've no idea if this would be durable in a pressure gauge, but he seems to have done quite a lot of experimentation with different approaches (for watches), so it's a start. Wilf
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Post by uuu on Nov 13, 2023 13:35:23 GMT
I've got the very part you're looking for - but can I find it? No.
You see I have a fixed steady, which clamps to the lathe bed in exactly the same way, with one fixing instead of two. I bet the nuts/plates are the same.
If no one else comes up with the answer before Wednesday, I will be visiting John at the Pump House, so can take a look at his one.
Wilf
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