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| New project started, double acting "steam" engine! |
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| John Hill:
OK, I got half the verandah painted so I have earned some 'shop time! Turning a few bits for the piston. This was a challenge until I figured that I could glue all the pieces together and use some trusty string to drive the work between centres, the string only broke once! These are the bits of the piston, those rubber washers were a failure and with no suitable thin leather at hand I am making do with some vinyl, time will tell! This will be an air engine (no steam) so I expect the vinyl will be OK at least for a while. All the bits so far, piston assembly on the left, spool valve, valve chamber and the cylinder with the cylinder head in place. |
| bogstandard:
John, If you can get your piston within 0.002" (0.05mm) clearance in the bore, no mechanical sealing would be needed. If you just cut a couple of very shallow oil rings around the piston, then the oil in the engine will form a perfectly good seal for what you are doing. I am not trying to say what you are doing is wrong, it is your build, but it could have saved you a little work, and your wife's vinyl corset wouldn't be full of circular holes. It might be something to consider for your next build. Seeing as you want to do extraordinary engines, maybe a sleeve valve next. Coming along great BTW. Finding and using your own little techniques to get the job done. John |
| John Hill:
Thanks John, I did consider the close fit piston route and could still go to that without any problem. The little nutating engine works well but it leaks so much air that the compresser runs more often than seems acceptable sp this time I am trying for a low leak solution. Dont worry about the corset, I cut the circles out of the back of the new sofa and it will not be noticed until we clean behind there! |
| John Hill:
No, this project has not been abandoned! Todays project was to make the small throw crank to drive the valve system. The throw is the same as the diameter of the crankshaft. Find some likeley bits of metal:- Put a long bit and a short bit in the drill and make a couple of holes:- Poke some thin stuff through to pin them togehter:- After a bit of careful work with the hacksaw it was time to carefully grind the crank pin using the recently made tool post grinder. (Looks like a couple of Bog's pidgeons came over and poopsied on it! :scratch:) It looks a bit rough, it should probably be thrown under the bench but maybe I can put some lipstick on it. :coffee: Ah, thats better, a bit of bondi and a puff of black paint hides most of the mess! |
| bogstandard:
If it works John, then no problems. No need to bling it up just because of us. Did your toolpost grinder work as you thought it would? John |
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