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Post by rocklicker on Jun 9, 2008 13:10:22 GMT -5
Alright, all this talk about big tumblers has get me going. I'm working on expanding my 1 barrel setup to a 3 barrel setup. I will be using 3.5ft shafts on pillow blocks with 3 15lb barrels (Starting with 2, adding the third later on).
Question is, what's a good diameter rod as far as support goes? I was going to go with 5/8 inch diameter shafts with black tubing around it to bring it up to 1 inch. Given there will be about 50lbs max on them is the shaft stock thick enough? I could maybe add an extra set of pillow blocks half way down the shafts. I'm trying to avoid having to get a bigger pulley to keep the speed down. Thanks, Steve
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Post by stoner on Jun 9, 2008 17:04:03 GMT -5
The 5/8" shafts should be plenty, but with the length being 3 1/2', I would definitely put a support in between somewhere. Make sure you use hardened steel for the shafts. The first set of rollers I used on my homemade tumbler were bought at Home Depot, and well, let's just say "Low prices are just the beginning"!!!! I replaced them with drill rod and they lasted much longer. If you need parts from the surplus store here in San Jose, let me know and I can pick them up for you.
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chadman
starting to spend too much on rocks
Member since March 2008
Posts: 106
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Post by chadman on Jun 10, 2008 3:14:52 GMT -5
The 5/8" shafts should be plenty, but with the length being 3 1/2', I would definitely put a support in between somewhere. Make sure you use hardened steel for the shafts. The first set of rollers I used on my homemade tumbler were bought at Home Depot, and well, let's just say "Low prices are just the beginning"!!!! I replaced them with drill rod and they lasted much longer. If you need parts from the surplus store here in San Jose, let me know and I can pick them up for you. I use the case hardened shafts from Mcmaster Carr. They work great. They are only hardened on the outside. Also they have abrasion resistant hose used for Peristaltic pumps that I use to put the shaft through to make the roller. I have run my old shafts for 2.5 years nonstop and they are running on my my new tumbler now with no sign or breakdown. Peristaltic pumps use bearings to squeeze a length of hose so that it pumps. Most often used for pumping blood. Also used in pumping concrete. Oh and 5/8" is what I use. The only problem with hardened shafts is that a hacksaw won't cut them. You either have to anneal them first or take them to a machine shop to cut them. I haven't tried a cutting torch on them. I'm sure it will cut them.
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oldgrouchy
starting to spend too much on rocks
Member since August 2006
Posts: 240
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Post by oldgrouchy on Jun 10, 2008 15:13:58 GMT -5
I had a buddy who ran a SCUBA shop who built a tumbler for polishing the inside of tanks using truck axels for the shafts! Got the shafts at the junkyard for next to nothing since hd did not care about the condition of the splines. His ran nonstop for years since he did the tanks for all the shops around.
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Post by bobby1 on Jun 10, 2008 18:00:04 GMT -5
I have 1'2' and 5/8" shafts that have run for more than 20 years with no wear. As long as the locking collars are firmly attached to the bearings there should be no wear on the shaft. I cover them with thick walled "Tygon" tubing from a plastics supplier. The covers will wear out about once a year or so, but they are easy to change out. Bob
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