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This is the stock shaft that needs to be duplicated. It is 8mm with a 8mm x 1.25 threaded end. The rotor is kept in position by a round key cross drilled in the shaft.
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This is the bottom side of the centrifuge rotor. It is some type of plastic with a bronze bushing. The round key mates in the slot.
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I started by center drilling a piece of scrap 5/8" round bar.
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Next I took down the diameter between centers.
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Cut the threaded portions. Because the old LeBlond lathe doesn't cut metric threads I substituted 5/16-20 UNC thread for the 8MMx1.25 metric thread. They are very close. I simply bought a standard nut to replace the metric one. The larger threads are 5/8-18 and are used to preload the bearings.
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Cut a snap ring groove.
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This is the spindle installed in the quill.
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Rotor installed with a couple vials. Note the reflective tape that will be used to measure the RPMs.
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First test.
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Running at 5000 rpm this rotor generates 3600 g.
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I left the machine to running at 5000 rpm over night. The sample finally cleared... of course the temperature changed overnight also so I suspect that was the cause.
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Pushing the RPMs into the danger zone. No telling how much this rotor will take. At this RPM it is at 4600 g.
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Disaster... at 7000 rpm (6036.8 g) one of the vial holders broke. All I found was the splatter mark and fragments of the vial. Glad the vials point downward.
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The top lip of the vial holder remained in the rotor. It appears the vial holder broke at the neck.
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Drew a sample (right) that had sat for a week in a cup following the last tests. I also drew a sample (left) that had been mixed up. When I drew the right sample into the syringe I could see it was notable more clear. Centrifuged the sample for a few minutes and it cleared right up. Note how much less material is in the tip of the sample. The left sample was centrifuged for 12 hours at 3600 g. The right sample was centrifuged for 10 minutes at 1300 g. The settled sample on the right is notably more clear.
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These are the same samples rotated a bit to show the difference of waste. Clearly long term settling of WVO plays an important part if clarity is important. In a heated system the heavier hydrogenated part that affects clarity isn't an issue.
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I found one of the large fragments of the vial holder.
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After the sample that was centrifuged over night was allowed to sit for a few hours it clouded back up. The control sample started clear and remained clear.
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