jamesp
Cave Dweller
Member since October 2012
Posts: 36,155
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Post by jamesp on Oct 5, 2020 7:23:41 GMT -5
Link to my google photos albumIt's alive! I've temporarily loaded (possibly overloaded) the drum with some stuff I started on a an old (now dead) vibratory tumbler for metal parts along with some stuff we collected at Lake Michigan yesterday. I'm still waiting on grit and ceramic media from therockshed, so I used the dried rock slurry (no metal) from the old machine that still had a fair bit of coarse SiC in it. This is more of a leak test, so I'm not too worried about either not making progress on the rocks or damaging them. If they improve, that is a bonus. I'll run it as is until the grit arrives.
The drum is a 12" piece of 6" schedule 40 with the T-Cone plugs mentioned above, so the internal volume is at least 255 cubic inches. How much grit should I use for this volume? The drum runs at 53 RPMs. I think that is about right, but I have smaller drive pulleys if I need to slow it down. I'm open to suggestions. Thank you all for the help both here and in private messages. I really appreciate it! A cup to a cup and a half does well for that size for step 1 and 220. AO 500-1000-polish I'd use 3/4 cup.
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gt3073b
off to a rocking start
Member since September 2020
Posts: 11
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Post by gt3073b on Oct 6, 2020 15:47:59 GMT -5
My abrasives and ceramic arrived Monday, so I checked the progress with the old slurry. There was definitely some smoothing going on but there were also a few impact chips on some of the smaller stones. I removed one of the large stones, added ceramic media and a cup of 60/90 SiC and a little bit of the old slurry to jump start the new slurry. It is much quieter now. Hopefully the ceramic will prevent the chipping. I'll check again in a week.
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gt3073b
off to a rocking start
Member since September 2020
Posts: 11
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Post by gt3073b on Oct 10, 2020 15:43:18 GMT -5
My girls and I checked the tumbler last night, and a cup of grit was completely worn out. About of 1/4 of the stones were very smooth and rounded with no defects, so we pulled them out to a bucket of water so we could keep running the rest of the batch a bit longer. I added another 1/2 cup of coarse grit and topped it with a few more small rocks that didn't need as much work as some of the stuff already in there. The added ceramic stopped the chipping, so we were glad to see that. I have nothing to base speed on, but it seems to cut faster than I would have expected. I was very pleasantly surprised to see as much progress as I did in just a few days.
Regarding the T-Cone caps, they seem to be holding up well. I tried closing one only finger tight but it leaked a little, so I cleaned the rubber and plastic parts and snugged it with a wrench. They remove easily with a wrench, unlike the normal PVC threaded cleanouts that jam. When they are closed tight, the slurry doesn't work its way up the threads. When it is loose enough to leak though, the threads had slurry on them and were a little harder to open, but nothing one hand on the drum and one on the wrench couldn't handle. The ABS isn't showing any visible wear on the mold lines, so hopefully these will hold up long term. A small rock could get jammed in the small rounded area where the wrench flats are, but so far so good. If these make it through the coarse step with no issues, I'll buy 2 more and run a second drum with the remaining 12" piece of pipe I have.
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