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Note the comment on the 'olive' shaped rotary in first photo. Claiming the sliding action plus 'folding' action at tapered ends of barrel increases efficiency.
A taper ended barrel could be fabricated by welding two 8" to 4" HDPE reducers together instead of an end cap on one end. Fernco caps could be used to seal both ends. Both Fernco's can be removed for thorough cleaning. Such a barrel would have close to a 20 pound capacity.
It looks like a barrel with that shape could help introduce lateral motion among the rocks.
Front load washing machines often have curved or offset paddles which induce motion along the axis of rotation.
The size of the angled portions to the horizontal length would need to be adjusted to maximize the effect of the tapered ends. Too much horizontal length would create zones that have typical tumbling motion.
It looks like a barrel with that shape could help introduce lateral motion among the rocks.
Front load washing machines often have curved or offset paddles which induce motion along the axis of rotation.
The size of the angled portions to the horizontal length would need to be adjusted to maximize the effect of the tapered ends. Too much horizontal length would create zones that have typical tumbling motion.
Definitely some food for thought.
Certainly one certain barrel geometry would create the most efficient step 1 tumble Brian.
Some where along the way I read that a hex shaped barrel is less aggressive than a perfectly round barrel for rock tumbling. What about a comparing the performance of two 10 pound barrels - one twice as long as the diameter and one as long as the diameter.
Lortone makes a 6 and a 12. They are both the same diameter but the 6 is simply half the length of the 12. Which would shape 12 pounds quicker, two 6's or one 12 ?
I started out with long PVC pipe barrels say 4 times longer than the diameter and later cut them down to three short barrels. It did not seem to change the shaping time. It took about 8 weeks and eight SiC recharges to shape pet coral to a decent shape with either set up.
People thinking outside of the box, reinventing the mousetrap. You don't know what is going to work until you try it.
Be sure to watch the newest show on the DIY Network, "In the kitchen with James."
Does that mean I get to work with one of those 30 year old hard bod actresses to replace my wife and have my way w/her ? If so in like flint no pun intended !
People thinking outside of the box, reinventing the mousetrap. You don't know what is going to work until you try it.
Be sure to watch the newest show on the DIY Network, "In the kitchen with James."
Does that mean I get to work with one of those 30 year old hard bod actresses to replace my wife and have my way w/her ? If so in like flint no pun intended !
Jim, yeah you go with that idea.....You didn't by any chance hit your head on one of those beams during one of your construction projects did you?
There are more things in heaven and earth, Horatio, Than are dreamt of in your philosophy.
Certainly one certain barrel geometry would create the most efficient step 1 tumble Brian.
Some where along the way I read that a hex shaped barrel is less aggressive than a perfectly round barrel for rock tumbling.
Interesting that you brought that up, jamesp, because I was wondering whether the hexagonal barrels actually helped. When I try to visualize what is going on in those barrels, I imagine that they would have almost a start-stop effect, or a slow movement-fast movement effect, when they encounter one of the sides. A round cross-section seems like it would have a more continuous motion.
I had two thoughts bouncing around in my head since you posted the picture of the olive-shaped barrel.
First, and this is connected to the hexagonal vs round barrel, is what would happen if the sides were not faceted but rounded? An extreme would be a spherical barrel. Would that be too much of an extreme where rocks get stuck in the depths of the diameter with a little lateral movement at the ends, assuming axial rotation. (A round barrel that was free to rotate on 3 separate axes could be very interesting! You could also introduce 2-axis motion using a cam system on one shaft to lift and lower one of the ends.)
A better approach seems to be a more olive shaped geometry where lateral motion would be less inhibited by the “depth” of the central portion.
My second thought was whether axial asymmetry would be more helpful. To go back to the hexagonal vs round barrel, what would happen if the sides of the hexagon were slanted in opposing directions, with 3 sides of the hexagon having a positive slope from one end to the other and the other 3 sides having a negative slope. That would encourage lateral movement 6 times per rotation.
Certainly one certain barrel geometry would create the most efficient step 1 tumble Brian.
Some where along the way I read that a hex shaped barrel is less aggressive than a perfectly round barrel for rock tumbling.
Interesting that you brought that up, jamesp, because I was wondering whether the hexagonal barrels actually helped. When I try to visualize what is going on in those barrels, I imagine that they would have almost a start-stop effect, or a slow movement-fast movement effect, when they encounter one of the sides. A round cross-section seems like it would have a more continuous motion.
I had two thoughts bouncing around in my head since you posted the picture of the olive-shaped barrel.
First, and this is connected to the hexagonal vs round barrel, is what would happen if the sides were not faceted but rounded? An extreme would be a spherical barrel. Would that be too much of an extreme where rocks get stuck in the depths of the diameter with a little lateral movement at the ends, assuming axial rotation. (A round barrel that was free to rotate on 3 separate axes could be very interesting! You could also introduce 2-axis motion using a cam system on one shaft to lift and lower one of the ends.)
A better approach seems to be a more olive shaped geometry where lateral motion would be less inhibited by the “depth” of the central portion.
My second thought was whether axial asymmetry would be more helpful. To go back to the hexagonal vs round barrel, what would happen if the sides of the hexagon were slanted in opposing directions, with 3 sides of the hexagon having a positive slope from one end to the other and the other 3 sides having a negative slope. That would encourage lateral movement 6 times per rotation.
The spherical barrel is a thought to behold. It would certainly have extreme mixing. One of the more influential effects on abrasive life was filling a standard round rotary barrel 60% full verses 85% full. 60% is way more aggressive and makes sense with the longer 'avalanche' with in.
Maybe this will shed some light on barrel shape. This odd barrel is 20 inches in diameter and was driven at only 12 rpm. It would bruise and chip 1" and bigger rocks terribly. It did fine with pea size to 3/4" rocks.
Another complex barrel is the Viking slant rotary. I have a video somewhere of it launching the rocks across the bottom of the barrel 3 times per revolution. Very interesting motion. My wife uses this tumbler to abrade metal parts; metal creates serious gases in a sealed barrel. A slant tumbler operates without a sealed barrel.
Interesting that you brought that up, jamesp, because I was wondering whether the hexagonal barrels actually helped. When I try to visualize what is going on in those barrels, I imagine that they would have almost a start-stop effect, or a slow movement-fast movement effect, when they encounter one of the sides. A round cross-section seems like it would have a more continuous motion.
I had two thoughts bouncing around in my head since you posted the picture of the olive-shaped barrel.
First, and this is connected to the hexagonal vs round barrel, is what would happen if the sides were not faceted but rounded? An extreme would be a spherical barrel. Would that be too much of an extreme where rocks get stuck in the depths of the diameter with a little lateral movement at the ends, assuming axial rotation. (A round barrel that was free to rotate on 3 separate axes could be very interesting! You could also introduce 2-axis motion using a cam system on one shaft to lift and lower one of the ends.)
A better approach seems to be a more olive shaped geometry where lateral motion would be less inhibited by the “depth” of the central portion.
My second thought was whether axial asymmetry would be more helpful. To go back to the hexagonal vs round barrel, what would happen if the sides of the hexagon were slanted in opposing directions, with 3 sides of the hexagon having a positive slope from one end to the other and the other 3 sides having a negative slope. That would encourage lateral movement 6 times per rotation.
The spherical barrel is a thought to behold. It would certainly have extreme mixing. One of the more influential effects on abrasive life was filling a standard round rotary barrel 60% full verses 85% full. 60% is way more aggressive and makes sense with the longer 'avalanche' with in.
Maybe this will shed some light on barrel shape. This odd barrel is 20 inches in diameter and was driven at only 12 rpm. It would bruise and chip 1" and bigger rocks terribly. It did fine with pea size to 3/4" rocks.
Another complex barrel is the Viking slant rotary. I have a video somewhere of it launching the rocks across the bottom of the barrel 3 times per revolution. Very interesting motion. My wife uses this tumbler to abrade metal parts; metal creates serious gases in a sealed barrel. A slant tumbler operates without a sealed barrel.
The alternating sides of the Viking barrel are exactly what I was thinking for a potential alternative to the hexagonal barrel.
That 20-incher certainly looks interesting. The rounded end looks like it could introduce some good movement if implemented in a smaller diameter version.
"The alternating sides of the Viking barrel are exactly what I was thinking for a potential alternative to the hexagonal barrel." Brian The rock movement can be videoed when the cap is removed on this Viking 'complex hex'. Unfortunately I terminated Vimeo where the video was stored so it is unavailable. Another to be made to store on Youtube next time it runs a load.
A large percentage of the rocks are kept in a constant state of sliding movement across the widest section of the barrel. There is much less of a dead zone as can be seen on a clear ended round barrel. I have no quantitative data on grinding rates as compared to a round barrel. The Viking is in bad mechanical shape so my wife uses it on light loads for roughing small lamp part surfaces for painting.
I may take measurements and weld up a larger duplicate by increasing the size of the barrel proportionately. Viking hired some serious engineer power to design their tumblers back when we had an industrial minded country. It is hard to say how much technical focus was placed on the barrel design but judging from the action of the rocks it may have been substantial.
The example in the photo above has been modified by retro fitting a gear motor. The original drive system is under built and is underpowered with a clock motor.
Bob Anxious to see what you come up with. Just keep in mind the industrial tumblers posted above seem to be intended for machine parts run in ceramic media. It may not make any difference if running rocks in them. I will say the Viking barrel above was designed to run rocks. It may be a better choice to model from.
I have been trying in my mind for almost a year to figure out how to build a prototype barrel for my idea. My idea takes the interior chamber of the barrel through the same 3D motion as the one shown, but will do it on the conventional 2-shafted base w/o first having to change the driven shafts from cylinders to cones. Not only that, but my idea can be an adapter to conventional radially-concentric barrels.
Almost every night when I lay down to sleep this challenge is what I fall asleep working on in my mind. I finally may have solved a way to make it using a laser beam to guide my cutting. What I really need is a fixed laser beam that can cut a rotating rubber object up to 1" thick. Or a continuous wire saw. Once it took me 11 years to solve an engineering problem by falling asleep with it on my mind. But it worked that time and maybe it might work again.
I have been trying in my mind for almost a year to figure out how to build a prototype barrel for my idea. My idea takes the interior chamber of the barrel through the same 3D motion as the one shown, but will do it on the conventional 2-shafted base w/o first having to change the driven shafts from cylinders to cones. Not only that, but my idea can be an adapter to conventional radially-concentric barrels.
Almost every night when I lay down to sleep this challenge is what I fall asleep working on in my mind. I finally may have solved a way to make it using a laser beam to guide my cutting. What I really need is a fixed laser beam that can cut a rotating rubber object up to 1" thick. Or a continuous wire saw. Once it took me 11 years to solve an engineering problem by falling asleep with it on my mind. But it worked that time and maybe it might work again.
I can say that Viking had some heavy hitter engineers. I own 2 of their machines, the funky rotary and their vibe. Their vibe is engineered using a lot of vibration analysis mathematics and expensive components on par with large industrial tub vibes. Vibration is all about mathematics and a little bit of firing off the hip or guess work. I too am an mech.engineer but not trained in the disciplines required to design such a vibe. A better word is unqualified. A good vibration analysis engineer could create a vibe with measured outcomes like acceleration/velocity/frequency/mass/input excitation/etc to best do the job. Due to the amount of variables it would likely be the only way to do the job.
So, I would assume the 6 sided complicated rotary probably has a similar level of mechanical technology applied to it also. Factors like slump technology and angular motion is also hard core mechanical engineering type mathematics and properties that could be applied to such a barrel. I do have enough knowledge to know the barrel design is likely much less of a mathematical/engineering challenge. Likely or maybe...it just depends on what type technology was used. My thoughts are to duplicate the Viking rotary verbatim but on a larger scale. Basically plagiarize the design lol. Why not, it appears some serious engineering has been applied to it. 10 or 11 gauge steel, a plasma cutter and a welder would do the job. It would be nice to use a 3-dim scanner to get the dimensions and crazy angles to cut the proportionately larger parts out with. And set the angles for welding the monster. Would prefer to cut 6 pieces of steel representing the six sides and fold the angles and then weld the six sides together. So a 3 dim scanner and cad cam software.
I still believe sheer speed, coarsest grit, round barrel, and best performing slurry is the fastest route to shaping rocks in step 1. Hex type shapes simply do not react well to high rotational speeds due to the violent impacts created. Including the Viking barrel. 6" to 8" round barrels can be run super fast like 80 to 100 rpm if slurry viscosity is tuned properly. So much simpler too.
jamesp I'm a partner in a commercial ammunition manufacturing business. When I started I built this rotary unit and instantly outgrew it, thus it's in storage waiting to be put in my rock shop when it's finished. I think it will be ok for my rocks.
If we were able to carry the love and tolerance shown here into the world as a whole and get anyone to follow the example set, who knows what could be born from that? Stonemon RIP
I will also put in a MrDeburr for my vibratory needs. They are the bomb for polishing brass and I hope it will do rocks too.
If we were able to carry the love and tolerance shown here into the world as a whole and get anyone to follow the example set, who knows what could be born from that? Stonemon RIP
Looks a little tricky to remove a barrel while the other seven are rolling. : )
Consider the Earth’s history as the old measure of the English yard, the distance from the King’s nose to the tip of his outstretched hand. One stroke of a nail file on his middle finger erases human history.
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Welcome to the Rock Tumbling Hobby Forum where we share a love of rocks and a sense of community as enduring as the stones we polish.
The RTH Forum of www.RockTumbling.com is an Amazon Associate site and we earn money from
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link for instance, or any of our various product ads and banners. By clicking our links every time you begin your Amazon shopping
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