Gallery, Projects and General > The Design Shop
An experimental engine
arnoldb:
Stew, thanks :). O gauge is 32mm or 1 1/4" between the tracks. 1 3/4 (45mm) is gauge 1 - which I wish I went for when I started off with the small locos. This loco will end up as a 16mm narrow gauge (well, very approximate) scale :lol:
Thanks Gerhard :beer: - I'll try to - though I've hit a snag that will slow things down a bit.
Yesterday evening when I started drawing up the frames I realised that some of the valve-gear components and the front wheel wanted to occupy the same space which is a physical near-impossibility, so today I spent re-designing the entire valve-gear and running simulations to get acceptable and near equal cut-off's for both forward and reverse gear settings, with measurements that actually make sense. I'm getting more and more respect for the engineers at the turn of the last century!
I think I'll spend some time drawing up the frame and gear parts in CAD first - which might take a while, as I'm a bit slow with that :palm:
:beer:, Arnold
NickG:
You're right, bet it's a fair job to design it so everything fits in there. Very challenging project this is but you'll get there. :bow:
arnoldb:
Thanks Nick :beer: - yes, it's a big challenge on a small scale... I'm sure I'll lose some battles along the way, but definitely not the war; I'm much too obstinate to allow that :lol:
This project has been waylaid a bit; I wanted to be much further along but the redesign and personal life interfered.
Re-designing the valve gear layout took quite a bit of time, but I think I'm close enough to continue now.
Today's bit - a start on the frames...
As the loco will be a bit on the narrow side, I want the frames to be fairly heavy to keep the centre of gravity as low as possible. I decided on using 3mm thick steel plate for the sides, and will use mild steel for the cross beams as well. The only 3mm plate I have is locked up in a fairly big sheet, and cutting a strip off it was a bit of a challenge. I could have tried man-handling it on the band saw, but that was just asking for a broken blade. Another option was using one of my angle grinders, but I don't like cutting thinnish plate with either of them; it takes a lot of concentration and makes a hell of a noise. Gas is a bit expensive, so I tend not to use my oxy-butane kit for cutting. So, I settled on the venerable jig saw with a suitable fine HSS blade for cutting thin steel:
Next I sawed of two suitable lengths from the strip and off to the drill press with a rubber-backed sanding pad mounted in it. After a bit of work, most of the rust and crud was gone from the plates:
A bit of clean-up followed on the mill; very carefully over the extended bits with a fine feed:
In retrospect, it would have been MUCH better to clamp the frames to a suitable length of thickish bar before clamping in the mill vise for that job!
Once I had both long sides parallel and to width, I squared up one reference edge as well:
Then I drilled holes for the cylinder mountings, axle bushes and valve gear mountings/bushes:
No lay-out; just coordinate drilled from the reference corner by using the mill's graduations.
Some holes followed for mounting the cross beams, and I finally split the two sides apart, de-burred and left off for the day:
There's still some more work to do on the frames, but at a later point - for now they are where I need them.
Regards, Arnold
Rob.Wilson:
Hi Arnold
This is the second time you have shown rusty steel in your posts :scratch: ,,, do you have it imported like that ,,,, as you have 12 months of sun , and an average annual rain fall on 0.001" ,,, sorry your metric 0.025 mm :lol: :lol: :lol: :lol: :poke: :poke: :poke: :D
Looking good mate
Rob :D
arnoldb:
:lol: :lol: Thanks mate :beer:
All the rusted bits are from being a cheapskate skip-diver :doh: - and generally just getting my hands on what I can find lying around scrap. I don't know what's up with the weather here this year though; had more than 250mm of rain in the last 2 weeks :scratch: - that's about what we get in a year. Don't like it... Makes tools rust and hides the sun :loco:
:beer:, Arnold
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