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| spuddevans:
Dunno how I missed this thread, but well done Arnold on another runner :clap: :thumbup: :clap: :thumbup: :clap: Nice and unusual engine. Tim |
| arnoldb:
Rob, Dave, Eric & Tim - thanks gents :beer: - apologies for the belated thank-you! I didn't post yesterday's work yesterday evening, as a social commitment ( :beer:) interfered :D Work started on the flywheel. I got a phosphor bronze off-cut from one of my suppliers - not cheap, but it was the best I could do: Started cleaning it up; this piece is just long enough to make two flywheels from. I've machined quite a bit of PB so far - always without any problems, but this piece was giving me some grief; it had soft and hard spots in it and was a bear to turn: Parting it off was no fun; my rear parting tool wouldn't touch it, even though I'd honed it up super sharp! So I tried my old jig-saw parting bit and that ran through it without any problems: After some more turning, I had the flywheel rim: Next I turned up the flywheel hub, and drilled six 2mm holes in it for spokes, and a 2.5mm hole between two spoke locations to tap M3 for a grub screw: While I had the dividing head mounted on the mill, I also drilled the rim for the spokes. The hard and soft spots made the drill wander quite a bit in each hole... Spokes were cut from 2mm brazing rod, and one end of each cleaned up with a file: The wandering of the drill in the rim made for a tight fit for the spokes through the rim; I had to resort to a small hammer to tap them in to just outside of the hub's radius. Then I set the hub on a piece of 6mm rod in the tailstock to help with positioning: I put a drop of retainer in each hole in the hub, and also on the bits of the spokes still sitting outside the hub. Then I tapped each spoke in. I then moved away the tailstock, and with the rod left in the hub, I clocked the hub as center as I could by lightly tapping the bits of spoke still sticking out of the rim. Because the holes through the rim had wandered, axial run-out would have caused a very wobbly flywheel - so I checked further away as well, and used the rod to bend the spokes slightly to get the wobble out: The flywheel was then set aside to let the retainer cure overnight. The spokes need to be filed or turned down later: On to some woodwork... Earlier this year while visiting, my father brought me a circular saw and a mounting table that my grandfather had very generously donated to me: I haven't used it yet as I steer away from woodwork in general, but now was the time to try it :dremel: The piece of teak I have for bases is quite difficult to cut with a jigsaw as I had done in the past - the circular saw did in seconds what used to take me many minutes to get done: A final cleanup of the uncut edges of the block was done on the mill: The piece of timber is very rough, and had spent quite a bit of time out-of-doors before I bought it, so all the faces are impregnated with dust and sand, so instead of breaking out the wood plane to plane down the flat faces, I used a very sharp HSS flycutter on the mill: That left a really smooth finish :D Mounting holes for the engine base was drilled - part-way 8mm and then 4mm through - to match some M4 countersink screws I have: I used a router bit to add a bit of detail - first on both cross-grain faces: As can be seen in the photo above, the cross grain faces splintered out a bit, but the splintered bits are in areas that would be removed when routing along the grain - without additional splinters coming off. After a final bit of work with sand paper, the base was looking OK: I then lavishly applied furniture wax to it, and set it in the sun to have the wax draw into the wood a bit. Work stopped there for yesterday - I'll carry on in another post for today's bit; have to finish uploading some things first :) :beer:, Arnold |
| arnoldb:
On to today's bit... The good news is the engine runs, but bad news is there's some of the last machining photos missing, as my camera's batteries gave out after the first photo and the spare set was flat as well :doh: To clean the bits of spoke sticking out of the flywheel, I trimmed them as close as I could with a side-cutter, and turned up a mandrel to mount the flywheel on. I just filed a flat on it for the grub screw to locate on to hold the flywheel in position: The batteries gave out and was put on charge, so some typing to explain what happened next: I turned the outside of the flywheel down very carefully - till the spoke ends were off and I then gave it a very light finishing pass across the rim. Even though I worked as carefully as I could, the interrupted cuts and finishing pass brought the rim into a wobble. As I can't fiddle with it too much, I trued it up as well as I could, but it still runs slightly wobbly :(; I should have silver soldered the spokes in instead of using the retainer. The waxed wooden base was given a vigorous rubbing with a soft cloth, more wax applied and more buffing with the cloth. I could have painted the base with clear varnish, but I just like the way waxed & polished wood looks, feels and smells - even if it needs a bit of wax every now and then. My sis knows the drill with the floor & furniture wax :coffee: I disassembled the engine and gave everything a final clean-over. All the finishes will be left as-is; the engine is fairly big (compared to my other builds) and I think polishing bits of it will be a bit too much on the eye. Also, polished surfaces need attention over time to keep them shiny, and the engine is actually quite delicate - if the cam ring bends slightly or pressure is exerted on the connecting rod or forks, it can go from a good runner to a non-runner in no time. After cleaning and final assembly (and charged batteries), the engine looks like this: I tried a couple of different locations for taking the finished photos; the above ones were the best lot from the lot, but this one is OK as well: After some oil on the cam; a bit too much :coffee: - it still runs very well: One of the aims of this engine was to have it run on breath power. It does, but still needs a bit more of running in. Please excuse the ugly mug intruding in the scene :lol:: My sister will hopefully visit in the next couple of weeks, then I can present it to her :ddb: :ddb: :nrocks: Another fun build done... Time to clean the machines, make a bit of tooling, and then on to the next engine. :beer:, Arnold |
| saw:
Congrat a fine peace of art :bow: :bow: :bow: :bow: :bow: :bow: :bow: :bow: :bow: :bow: :bow: :bow: :bow: :bow: :bow: :bow: :bow: :bow: :bow: :bow: :bow: :bow: :bow: :bow: :bow: :bow: |
| Stilldrillin:
Really top class build Arnold! :clap: :clap: Classy woodwork. :thumbup: I can't see any flywheel wobability! :scratch: Well done! :D David D |
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