paul
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Posts: 8
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Post by paul on Dec 3, 2007 21:55:29 GMT
Thought I'd start a new image thread for my uber-simple single acting twin oscillator rather than pollute other threads  Here's the state of play with cylinders/covers/pistons/rods/big-ends pretty much finished and one port block part-drilled. Ignore the giant sized temporary fasteners. My plan took a bit of a knock when I discovered that the angle I have is 'twisted' along its length and nothing like a right-angle in cross section - never mind, it's just a case of tweeking a little I've made/used 3 jigs so far to get things lined up and I had to make each of those several times to get them just so  Still cheaper in steel than brass eh?  |
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paul
Member
Posts: 8
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Post by paul on Dec 19, 2007 20:31:15 GMT
Switched the hex format big ends for round ones, did most of the drilling etc for the ports/pivots/crank, made some crank webs(wheels really). Next I'm going to fix the cranks with grub screws - I cross-drilled each end of the shaft and added a 3mm countersink to those holes to lock the grub screws in place. Then trim off the crank-pin thingies and make some pivots. Exhaust will be taken out the 'back' (left-hand) end via a 1.5mm hole drilled along the angle i.e. at 90deg to the port. I'm going to have cross-members at each end to hold the port blocks at the right distance, the one at the ports end also acting as a steam inlet. Possibly!  Ignore the temporary fasteners and the popped-out piston! |
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paul
Member
Posts: 8
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Post by paul on Dec 23, 2007 20:49:34 GMT
Test assembly on a scrap of wood to see if I got the cranks lined up properly (temporary monster grub screws an' all). Looks ok  Also visible the fruits of todays labour - the jig-thing for making the custom size screws needed to hold the cylinder covers on and the first screw so made.  |
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paul
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Posts: 8
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Post by paul on Dec 26, 2007 20:45:47 GMT
It's a one man thread! Made the screws for the cylinder covers, the pivots, the web grubscrews and almost finished the flywheel. A productive Boxing Day for a change!  |
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Post by baggo on Dec 27, 2007 1:41:25 GMT
You seem to be doing a pretty good job on yer own Paul ! |
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paul
Member
Posts: 8
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Post by paul on Dec 27, 2007 8:01:12 GMT
Awww, now you've gone and spoiled it! |
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paul
Member
Posts: 8
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Post by paul on Dec 27, 2007 19:47:26 GMT
Filed the port blocks (brass angle) to size and perpendicularity (!) and created the chunky steel base bits. Change of plan on the flywheel front - got rid of the flanges either side to reduce weight; now plan to put a grub screw in to lock it in place.  It seems that the dimensions on the drawings on which I've roughly based this model are wrong - the piston rods are about 4mm too short so that's tomorrows job! Does anyone know what if anything would happen if the piston were to occlude the cylinder port (if the rods were too long)? I can't see that it would make much difference except that the power stroke would begin under flywheel-power only until the steam was admitted. Just wondered! |
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paul
Member
Posts: 8
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Post by paul on Dec 28, 2007 21:50:48 GMT
Didn't get round to remaking the rods but I did make the cross-members for the base, threaded the base to accept the port blocks, made a couple of brass bolts and drilled/threaded for the flywheel grubscrew.  I showed the image to a friend. He described it as 'workman-like'. I was happy as that's where I was aiming and with the chunky base it weights a ton for a little 'un! |
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paul
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Posts: 8
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Post by paul on Jan 12, 2008 22:08:20 GMT
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Post by havoc on Jan 13, 2008 12:23:43 GMT
Paul, if it can run on 5psi (whatever that is in real units) then it can't be "badly made". Certainly not if that was one of the first tests and it still needs some breaking in. I must say that it looks larger in your hand than on the photos above.
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paul
Member
Posts: 8
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Post by paul on Jan 19, 2008 15:31:26 GMT
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Still cheaper in steel than brass eh?