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Post by knave on Mar 13, 2020 23:25:39 GMT -5
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Post by knave on Mar 14, 2020 0:11:50 GMT -5
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reynedrop
starting to spend too much on rocks
Member since February 2020
Posts: 204
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Post by reynedrop on Mar 14, 2020 0:34:14 GMT -5
K so I downloaded it (Apple) and all it does is strobe my flashlight at a set speed...?
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Benathema
has rocks in the head
God chased me down and made sure I knew He was real June 20, 2022. I've been on a Divine Mission.
Member since November 2019
Posts: 703
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Post by Benathema on Mar 14, 2020 1:08:08 GMT -5
K so I downloaded it (Apple) and all it does is strobe my flashlight at a set speed...? I have faith
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reynedrop
starting to spend too much on rocks
Member since February 2020
Posts: 204
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Post by reynedrop on Mar 14, 2020 1:16:20 GMT -5
K so I downloaded it (Apple) and all it does is strobe my flashlight at a set speed...? I have faith At no point did my tumblers appear to stationary or seem to maybe stop spinning with lights strobing at different speeds. I played around with it for a tiny bit before getting frustrated. I just want an app that will do the work for me, because clearly I suck.
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Benathema
has rocks in the head
God chased me down and made sure I knew He was real June 20, 2022. I've been on a Divine Mission.
Member since November 2019
Posts: 703
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Post by Benathema on Mar 14, 2020 1:42:49 GMT -5
Okay, well, super low tech way of doing this. Make a sharpie mark on your barrel. Mine already have labels to identify which one is which, so simple enough.
Pull up a stopwatch app - it may already be on your phone, or a part of an alarm clock app. The moment the mark on the barrel reaches the edge of the frame, hit go on the stopwatch and count the number of times the mark passes the frame in one minute. You might get a fraction of a rotation at the 60 second mark, but that's close enough.
33B should be going near ~60 or so RPMs.
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shardy
starting to spend too much on rocks
Member since October 2019
Posts: 110
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Post by shardy on Mar 14, 2020 2:56:13 GMT -5
60? Wow. I was playing with pulley arrangements one night and tried 75, rock soup.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Mar 14, 2020 4:43:25 GMT -5
Old school calculation.(for us members that can not make a cell phone dance) 4 measurements and knowing the motor rpm will do the trick. Rock tumblers are double reduction machines so you multiply a fraction times a fraction times the motor speed.
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Post by knave on Mar 14, 2020 5:42:41 GMT -5
K so I downloaded it (Apple) and all it does is strobe my flashlight at a set speed...? A real stroboscope uses a much stronger flash bulb, and works many times better than the app. But for low RPM measurements the app does just fine. Turn the phone so you can see the flash, then watch a mark or wing nut on the barrel, adjust the app frequency so the flash happens exactly when the mark comes round and stares you in the face. Hopefully this is clear as a Montana agate, but I have noticed my explanations are lacking lately. Evan
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Post by knave on Mar 14, 2020 5:50:14 GMT -5
Old school calculation.(for us members that can not make a cell phone dance) 4 measurements and knowing the motor rpm will do the trick. Rock tumblers are double reduction machines so you multiply a fraction times a fraction times the motor speed. This super-simple formula is the e=mc2 of the tumbling world. In design for sure. With the stock Thumbler B, belt slipping is more common than we think. The motor is happily spinning, but grinding the belt (oring) more than my rough. You can wait until it squeaks and piles black dust on your table, or you can check it every week with the strobe app. Find out where it runs normally and mark the rpms down. Then you can quickly set the app for that speed, and check if the barrel has slowed down. PS. Not necessary for machines built like an Abrams tank...
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pizzano
Cave Dweller
Member since February 2018
Posts: 1,390
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Post by pizzano on Mar 14, 2020 5:51:47 GMT -5
Okay, well, super low tech way of doing this. Make a sharpie mark on your barrel. Mine already have labels to identify which one is which, so simple enough. Pull up a stopwatch app - it may already be on your phone, or a part of an alarm clock app. The moment the mark on the barrel reaches the edge of the frame, hit go on the stopwatch and count the number of times the mark passes the frame in one minute. You might get a fraction of a rotation at the 60 second mark, but that's close enough. 33B should be going near ~60 or so RPMs. What's "super low tech" about that.........?
That method/application or similar, is still used for timing applications on older engines, pacing track laps for races (vehicle/human), tracking band saw blade rpm's, the list goes on.........old school tech still has a place in this "modern" world.........lol
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Post by knave on Mar 14, 2020 5:58:34 GMT -5
We’ve had a few asking about barrels running too fast or slow lately. It’s easy to guesstimate (WAG), and say HMMmm that’s goes around twice as I count 1 second under my breath, so that barrel is obviously 120 RPM, lol. After coffee, Red Bull, or when surrounded by beautiful rocks, the mental (count) becomes faster, along with our heartbeat. Some days are just faster than others I guess. A strobe app or a longhand formula is not affected by the political environment or the space-time of a rotating tumbler.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Mar 14, 2020 6:41:25 GMT -5
I bought a 8" PVC pipe barrel way back when knave. It was thin wall (hard)PVC known as drainage pipe - SDR 35. Fernco cap, held 18 pounds rock. Started the barrel on the over built home made tumbler. The shoulder at the 8" to 4" bell reducer wore thru before 2 months running step 1 with SiC 46. Called the guy raising hell. He asked what speed, I told him 24 rpm(8" diameter). He asked me to raise the speed to 50 rpm. Why ? He said slippage. I said where ?! He said the rocks were sliding up and down the barrel creating a lot of abrasion. Internal slippage. He was correct. You could barely hear the rocks climb and slid back down the barrel wall continuously. This is the point I want to make. I sped the it up and his barrels would last 9 months to a year at 50 rpm doing SiC 46. Seemed to eliminate internal slippage. Still unacceptable, so I made my own PVC barrels out of heavier sch 40 pipe. Life went to 3 years running SiC 30/46 full time. If, I maintained at least 30 rpm. AND used slurry additives that did not cause slippage. Schedule 40 PVC is softer than the SDR 35 pvc and grips rocks better. So the slower non-slip speeds. In general softer materials like rubber resist abrasion better, slip less. Using non-foaming machine dishwasher detergent was acceptable to use as a lubricant in the PVC barrel but also caused internal slippage at low speeds due to being so slick. An awareness of internal slippage should always be considered. Neither a calculation or a strobe will catch it.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Mar 14, 2020 7:05:35 GMT -5
A note about barrel speed. Speed can damage rocks, #1 concern. The percent fill and slurry thickness has a big effect on damaging rocks; other than running big rocks or small rocks they are the 2 most influential impacts. A 50% full barrel running with water is probably 5 to 10 times more violent than an 80% full barrel running with a thickened slurry both at same speed. Here is an extreme case: Running step 1(ONLY) - a 16 pound barrel of thin 15 to 22 gram glass shards at 80 rpm, big 9 inch diameter barrel, 80+% fill and thickened slurry. There was almost no noise radiating from the barrel. Not one broken piece of glass. Check out final polish out of vibe, no frost damage:
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reynedrop
starting to spend too much on rocks
Member since February 2020
Posts: 204
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Post by reynedrop on Mar 14, 2020 22:47:18 GMT -5
K so I downloaded it (Apple) and all it does is strobe my flashlight at a set speed...? A real stroboscope uses a much stronger flash bulb, and works many times better than the app. But for low RPM measurements the app does just fine. Turn the phone so you can see the flash, then watch a mark or wing nut on the barrel, adjust the app frequency so the flash happens exactly when the mark comes round and stares you in the face. Hopefully this is clear as a Montana agate, but I have noticed my explanations are lacking lately. Evan I've decided it's my eyes that are the problem. Oh well.
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shardy
starting to spend too much on rocks
Member since October 2019
Posts: 110
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Post by shardy on Mar 14, 2020 23:18:24 GMT -5
It's a cool app to verify speed. Calculations had my fast rollers at 56. App says 58.
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reynedrop
starting to spend too much on rocks
Member since February 2020
Posts: 204
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Post by reynedrop on Mar 14, 2020 23:51:37 GMT -5
A note about barrel speed. Speed can damage rocks, #1 concern. The percent fill and slurry thickness has a big effect on damaging rocks; other than running big rocks or small rocks they are the 2 most influential impacts. A 50% full barrel running with water is probably 5 to 10 times more violent than an 80% full barrel running with a thickened slurry both at same speed. This makes a lot of sense. The small tumbler I have runs at 3 speeds, and the manual recommended running coarse at the highest speed (no idea on RPMs). With my fragile rocks, like rainbow moonstone and labradorite, it would've been much better to run at slower speed. It wasn't loud at first, according to husband, but the second week in coarse, he complained about the noise significantly. I noticed a significant amount more damage to my rocks, too. I did reduce speed in medium, and added plastic pellets, but the barrel fullness was naturally reduced. Still had more new damage than I wanted. Now that it's in pre-polish, I have more plastic pellets and speed is at lowest setting. I think next time I try fragile stones, I'll thicken slurry and run at lowest speed for the entire process.
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reynedrop
starting to spend too much on rocks
Member since February 2020
Posts: 204
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Post by reynedrop on Mar 14, 2020 23:53:01 GMT -5
Old school calculation.(for us members that can not make a cell phone dance) 4 measurements and knowing the motor rpm will do the trick. Rock tumblers are double reduction machines so you multiply a fraction times a fraction times the motor speed. So, besides the barrel and shaft diameters, which I can easily measure, how do you find out motor RPM and pulley diameters? My small tumbler doesn't list any specifications.
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jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
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Post by jamesp on Mar 15, 2020 10:55:50 GMT -5
The pulleys or sheaves are the 2 discs that the belt slip on to. There should be a small one on the motor and a big one on one of the shafts. Mavbe 1 inch(on motor) and the other is 4 inches(on shaft). pulleys or sheaves. However some tumblers use gears reynedrop: One tumbler is a 3 speed ? That makes things a bit more complicated. You would have to know the 3 motor speeds. Some motors have the rpm rating stamped on them, others may not. Or possibly the specification sheet mentions the motor speed. Most tumblers are under 60rpm meaning that you can easily physically count the number of spins per minute as Benathema mentioned. By putting a mark or piece of tape on the barrel and count the number of times the mark or tape passes over the top as barrel spins over a 60 second period of time. (A piece of tape shouldn't leave a mark on the tumbler)remember me, my feelings were hurt when you made a comment about my dirty tumbler. I am ok now after intense therapy sessions. I only have 3 more sessions left ! Have you ever used your cell as a chronograph(stop watch) ? Or watching the second hand on a clock make one rotation ? 50 barrel rotations in 60 seconds = 50 rpm. Simple as that. The 3 speed tumbler must spin at a very slow at low and middle speed; the barrel probably turns only 30 times in 60 seconds in low. Maybe 45 times in 60 seconds in middle. Should be easy to count barrel rotations. A fast tumbler rotation would be 60 rpm, or one barrel rotation per second and also easy to count physically.
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Post by knave on Mar 15, 2020 11:07:55 GMT -5
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