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| sbwhart:
Thanks Dave Hard luck with the motor :doh: By way of a confession I scrap a cylinders when drilling a hole for the ball bearing, so made two new ones, I didn't take any pics but I tried a new idea out to make them. I chucked the bar up with enough material sticking out to make two cylinders, skimmed down the OD and drilled the centre hole, then transfered the chuck with the bar in place over to the mill, used the trick of having the chuck lose and centring to the quill with the hole using a centre, then clamping the chuck up, then used the PCD feature on my DRO to drill the rest of the holes drilled right through both cylinders, transfering the chuck back over to the lathe, parting off the cylinders, its given me cylinders that have bores that are dead in line with each other in any position, hopefully they will work great. Cheers Stew |
| madjackghengis:
Stew, I've been considering the forces at work in these elbow engines, mostly because I've seen one with the pistons hinged, actuallly run, yet the majority of the story is if there is the slightest detail in alignment off, they are locked up. What I've come up with is this: if the pistons move in and out no more than their diameter, and if the piston remaining in the cylinder is more than twice the diameter long, they can be hinged as the bearing surface remaining in the cylinder is sufficient to keep the two pistons in full alignment. In some of the hydrostatic motors I work on, the pistons are at least three times the length of their working stroke, while those which have the stroke and bore less than this ratio invariably use balls for pistons, as the ball generates no twist or leverage against its self as a piston would, if cocked in the cylinder as out of square by any means would entail. I think with this understanding, I am soon to try my hand at an "elbow engine", even just to put on my wife's chair side table to keep her occupied and not yelling at me to do something useful. I've been considering that elbow engine I saw work forty years ago with hinged pistons, and had to come up with a rational explanation on how it could work, and only just realised all the conditions necessary for such a thing. Great job on the engine, it's good to see something work the first time out, and so often it takes weeks to work out the bugs. Cheers :clap: :thumbup: :clap: :thumbup: :bugeye:Mad Jack |
| sbwhart:
Hi Jack Thats some interesting ideas you've floated there, I toyed with the idea of having an hinged elbow using rubber, the sort of stuff they use for suspension bumpers on cars. Cheers Stew |
| rleete:
Nice cylinders. Wish I'd thought of it. |
| sbwhart:
Thanks Rleete This ones going on fleabay so I wanted to make it a little bit special. Finished off the fly wheel fastened the hub to the rim using heigh strength loctite let it do its curing thing for a couple of hours, then set it up true in the lathe and bore for a nice fit on the cylinder. Again fastened cylinder to the fly wheel with loctite, this is what its looking like. Made a start on the base I'll already got it cut to size and some holes drilled, so made a start drilling the long 1/8" dia air ways with a long series drill. This is the set up I use a little complicated but I want to keep every thing aligned. And this is what happens when you rush, the drill broke leaving a bit in the job, nothing for it but to start again. Decided to call it a day. Our daughter is due to give birth any time to our first grandchild so I'm a bit on edge. Have fun Stew |
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