I built a rotary tumbler, bought 20lbs of media and was wondering how much I should put in the container. I don't seem to remember reading that particular step anywhere. With a 1750 rpm motor, what are good pulley sizes to run? I have 1.5" on the motor and a 6" on the shaft. I was thinking of going to a 8" or 10" on the shaft.
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Tumbler/media question
- Thread starter Lo/Rez
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Stacy E. Apelt - Bladesmith
ilmarinen - MODERATOR
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I am assuming this is a horizontal barrel on a rotating shaft cradle. You didn't say what the roller shaft and barrel sizes was, but all you have to do is work out the ratios and divide them into 1750 to get the final RPM. A 10-12" barrel should turn between 20 and 30 RPM.
Just as an example:
If the roller shaft has a 1" rubber rollers and the barrel is 12", then that is a 12:1 ratio. If the motor has a 1.5" pulley and the roller shaft has a 8" pulley, that is a tad over 5:1. The combination is roughly 60:1. Driven by a 1750 RPM motor, that would reduce the barrel speed to roughly 30 RPM. A 10" pulley on the roller shaft would yield about 20 RPM.
Just as an example:
If the roller shaft has a 1" rubber rollers and the barrel is 12", then that is a 12:1 ratio. If the motor has a 1.5" pulley and the roller shaft has a 8" pulley, that is a tad over 5:1. The combination is roughly 60:1. Driven by a 1750 RPM motor, that would reduce the barrel speed to roughly 30 RPM. A 10" pulley on the roller shaft would yield about 20 RPM.
Stacy E. Apelt - Bladesmith
ilmarinen - MODERATOR
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A 7-8" barrel should turn around 30-40 max RPM. That would be a gear ratio of 50-40:1 ( 1750 motor). With a 1" roller, 8" tank, 1.5" drive pulley, the shaft pulley would be a pulley between 5" and 7". An 8" pulley would be slower, which might be better for tumbling knives and fittings. On larger items, the speed needs to slow down.
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What media type are you using?
/DP
/DP
I bought 20lbs of aggressive cut media on eBay. The finish doesn't look too bad, but I would like to get some less aggressive media and try a two step process.
This is after two hours of tumbling. It's hard to take a decent pic with a cell phone but you can barely see the grind marks under the finish if you look at it a certain way. I covered over the makers mark with nail polish as I tumbled this one with the handle on.
It was pretty shiny and I thought it would probably scratch easy so that is why I decided to try tumbling it.
This is after two hours of tumbling. It's hard to take a decent pic with a cell phone but you can barely see the grind marks under the finish if you look at it a certain way. I covered over the makers mark with nail polish as I tumbled this one with the handle on.
It was pretty shiny and I thought it would probably scratch easy so that is why I decided to try tumbling it.
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