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  1. #21
    Join Date
    Apr 2005
    Posts
    903
    You did a great job on the fabrication and a great design. I've designed a few but never got around to making one. I guess I was hoping some parts would drop in my lap so I would have to buy them.

    Just a thought, you might consider mounting your weights to the ends of the shaft. A simple plate with a slot across the middle would allow you to adjust the offset to control the vibration. It would be an easy way to tune the machine without having to make new weights.

  2. #22
    Join Date
    Dec 2004
    Posts
    524
    As I understand it, the eccentric weights causes the whole thing to shake.

    Why can't the motor drive an eccentric connected to the barrel to cause it to move directly? What am I missing?

    Ken
    Kenneth Lerman
    55 Main Street
    Newtown, CT 06470

  3. #23
    Join Date
    Jan 2004
    Posts
    539
    Actually you want the parts to go top to bottom. In a rotating fashion. You have a big tub, you will need (want) a lot of media. Here are a couple of places that I have got media and compounds from in the past. Very knowledgeable in all aspects of mass finishing.
    Gary

    http://www.vibratoryfinishing.com/

    http://www.candmtopline.com/frames.html

  4. #24
    Join Date
    Sep 2005
    Posts
    86
    Thanks for the sources of media. I'll give both places a call Monday.

    I ran it a bit more yesterday. Definately need more media. It does have a nice top to bottom circulation going on. With this amount of media, it takes about a minute to turn completely over in the tub.

    The finish isn't quite there yet. It's alright after 30 minutes. 2 or 3 swipes with a scotch brite pad cleans it up. I think with a bit more aggressive media and the propper compound, I'll be there.

    I let all the water that had previuosly been in the tub drain into a bucket overnight. From 2 gallons of water, I got about a 1/4" of aluminum clay in the bottom of the bucket. I dumped the water into a large tub and put a fan in front of it to see how long it would take to evaporate.

    This has me thinking that I will incorporate a setteling tank and filter into the sprayer system. I'm thinking that I'll park the pump up high in a 5 gallon bucket so that the crud can accumulate at the bottom. If I lined the bucket with a plastic bag, I could just let the goo build up to a certain point. Once it was "full", I could dump the water into the shaker tub with the drain closed and just change out the bag.

    Ken,
    You are correct in that the weights cause the whole thing to shake. The were a couple reasons why I chose not to just mount a weight on the motor. From the outset, I figured that different materials may need different frequencies to be adequately finished. This would mean that I needed an easy way of changing the speed that the weights spin. Using different sized pulleys to vary the alxe rpms seemed like the easiest, and most economical route.
    The other reason is that I did not want to have all that weight swinging directly on the motor's shaft. The amount of force necessary to lift 300lbs of media and 100 pounds of frame, tub and parts 1000 times a minute would probably make short work of the bearings inside of a 25year old air compressor motor. With the setup I'm using, the force of the swinging weights goes through 4 1" ball bearings mounted in pillow blocks, which are all bolted to the cradle assembly. The motor still gets some side loads from the frame hopping up and down, varying the tension on the belt. But those loads are much less in size and harshness than they would be swinging the weight on the motor.


    I considered the weights on the end of the axle shaft, but I am worried about something coming loose and ricochetting around the shop. My "weights" are 2 6" lengths of 3.5" aluminum tube, with a 1/2" wall. The axle goes through the tubes, and the tubes are bolted to the axle. If the weight mounting bolts were to break, the weight would just spin on the alxe. They would have to go through one of the bearing assemblies or the .5" wall tubing would have to come apart for anything to fly off of the axle. The largest piece that could come off the assembly is a bolt head.

    To add weight, I figure I could use stick-on lead wheel weights. To remove weight, I will have to take them off and run them through the band saw.

  5. #25
    Join Date
    Aug 2003
    Posts
    143
    The way to make your weights adjustable is to use two identicle eccentric weights right next to each other. These two weights would clamp around the shaft and their position on the shaft would be adjustable. When you adjust them 180 degrees from each other the shaft will be balanced and you will have zero vibration. When you line them up with each other you will have maximum vibration.

    The weights I use are simply one inch thick steel disks with holes bored through them off center. They are a slip fit on the shaft and have set screws that allow me to adjust their position around the shaft. This way I can fine tune the magnitude of the vibration to a great deal of accuracy.
    Patrick;
    The Sober Pollock

  6. #26
    Join Date
    Dec 2004
    Posts
    524
    I'm not very familiar with vibe finishers.

    Suppose I had 12 inch lengths of 4 x 4 (with .125 wall) aluminum extrusions. How many could I finish in your 55 gallon tub at once? At what point will they start banging against one another and be scratched?

    Ken
    Kenneth Lerman
    55 Main Street
    Newtown, CT 06470

  7. #27
    Join Date
    Sep 2005
    Posts
    86
    Those are good questions, Ken.
    That size, I would guess 6-10 pieces...but that's just a guess. I won't know for sure until I fill it up with a good load of media.
    With the 50 lbs that I've got, I was doing 3 right triangular shaped pieces measuring about 13" x 9" x 9". They seemed to stay reasonably separated, but they kept swimming to the surface, and I'd have to shove them back down into the media.

  8. #28
    Join Date
    Sep 2005
    Posts
    86
    I've made some progress the last week or so.
    250 lbs of media filled the tub about as high as I need it to be. Any higher and the sprayer would get blocked. The media has a pretty good tumbling movement going on. The whole load tumbles over about every 5-7 minutes.

    I hooked up a better pump. Nothing fancy, Harbor Freight's second crappiest pump. I had to add 2 more drains, for a total of 3. With one drain, it would plug every now and then and the pump would empty the bucket. The water also foams up, which also slows drainage. I've got some liquid burnisher/special soap stuff on the way. I'm hoping that takes care of the foaming and maybe speeds up the process a bit.

    Right now, it takes 20-30 minutes to do a part. Parts come out with nice bur-free edges. The finish is pretty even. You can see marks from the media, but it's a pretty cool looking result. We'll see how they look anodized in a week or so.

    Maybe the most important upgrade has been the sound proof box. Maybe not sound proof, but definately sound resistant. The box is made with a layer of 2" polystyrene glued to 3/4" particle board. I routed a 1" step into the foam so that the corners would sort of key together. The foam was glued to the particle board with Liquid Nails. Then the particle board was screwed together at the corners. I also made a top with a routed step in the foam so that the lid fits tightly. Before the box, ear muffs were necessary whenever the shaker was run. With the box, you can stand next to it and have a conversation without having to scream. I think I'm going to try attaching some mover's blankets to the inside of the box to see if I can quiet it down further. This box has worked so well that I'm thinking of making one for the air compressor.

  9. #29
    Join Date
    Oct 2005
    Posts
    4

    How To Kepp 'Em Apart...

    "...At what point will they start banging against one another and be scratched?..."

    Just wanted to toss a solution in here...

    Commercial burnishers can be retrofitted with polystyrene seperators - that's one reason most of them have grooved cast-in liners. We made our own divider for the big machine when I found out how pricey the factory dividers were. Two pieces of angle iron, a 3/4" piece of white poly cut to shape, with (5) 2" holes drilled in a star pattern to let the media flow thru, and Voila - no more parts contact.

    Depending on how many pieces you need to finish, and the tank length, you COULD make as many dividers as needed for a particular client's work.

    OTOH, I occasionally polish custom racing vacuum pumps for a major manufacturer in my small machine, and they do just fine clumped in there 6 at a time - never had a hammer mark yet.

    So - there ya go !

    Best to all and Happy Thanksgiving !
    SC

  10. #30
    Join Date
    Dec 2004
    Posts
    185
    Hi Guys, did some experimenting some years back. I had loads of long Aluminium bars that we had to finish after milling. I built a rotating drum finisher and popped the parts inside with abrasives and set it going. results was less than satisfying! the rolling action rounded the ends much more than the middle and i had to go back to the hand finishing scene with scotchbrite and rubbing compound. i would imagine that this would be the case with the tire idea as well!
    a tip for those who want to experiment with the counterweights on the vibratory finisher: add two eccentrics per side. if you then rotate the two same side ones relative to each other you can set up any amplitude between zero (two weights opposing each other) and max (with both on she same side of the shaft)

  11. #31
    Join Date
    Jun 2005
    Posts
    71
    Can you really vibe Aluminum to a mirror polish?

  12. #32
    Join Date
    Oct 2005
    Posts
    4
    Yes ~ most grades of smooth aluminum can be polished to a very high shine.

    You must use the correct type of polishing media [MicroBrite works well], polishing soap [R43], and experiment with the water volume to get exactly the finish required for your particular vibratory polisher.

    SC

  13. #33
    Join Date
    Feb 2006
    Posts
    1187
    Hey Unabiker, How many of thos guards can you put in your vibratory? And what about parts bumping into each other and causing damage?

  14. #34
    Join Date
    May 2004
    Posts
    200
    Question in genral
    I have some car parts that are a zinc Aluminum alloy.. I was wondering if a vibratory polisher would work.

    To Unabiker
    Also I was wondering if more picture could be posted of the underside of the DYI unit

  15. #35
    Join Date
    Mar 2006
    Posts
    1
    any updates?
    I'm going to be making something very similar soon, for polishing 24" 5/16 brass and (sometimes) aluminum rods. I have some spare 55gal steel drums, a 1/2hp 3650rpm motor sitting around. I'm also considering using a 2hp 3phase motor and a VFD. I know the 2hp will be better for large batches of media and parts and that I can experiment with speed much easier with a VFD.

    I learned a lot from this thread so far, thanks.

    how are your parts turning out?

  16. #36
    Join Date
    Jun 2006
    Posts
    7
    G'day
    I am looking to do the same and build my own machine. Just wondering with your design does the media rotate from the outsides inward to the centre? And when the drum is full do your parts still float to the surface? What difference do you think it would make if the vibrating shaft was mounted lateraly as oposed to the longditudanal? As I am considering mounting it to the garage floor ( concrete ) I dont want to damage the house through excessive vibration, do you think that the feet could be mounted on vibration damping mounts or would this just cause the machine to bounce around uncontrolably or negate the vibrations in the drum?

    Cheers
    Fred

  17. #37
    Join Date
    Mar 2004
    Posts
    15
    Quote Originally Posted by Fred Nerk
    G'day
    I am considering mounting it to the garage floor ( concrete ) I dont want to damage the house through excessive vibration, do you think that the feet could be mounted on vibration damping mounts or would this just cause the machine to bounce around uncontrolably or negate the vibrations in the drum?

    Cheers
    Fred
    I would think a solid mounted frame would be best to avoid losing energy in a secondary non productive vibration. Mounting the machine to your floor would be fine with concrete anchors epoxied into holes (at least 3 inches deep) in the concrete to attach it with. We use a similar mounting system for rail where I work, and its suitable for passenger trains to travel over. I doubt your concrete would suffer with proper mounting hardware and dampening of the vibrator from the frame.

    But if you are really concerned about it a seperate high strength concrete "plinth", an elevated concrete pad with rebar reinforcement could be poured onto a section of your floor (after the floor surface has been prepared by roughing it and priming it) to mount the machines frame to, and that would virtually guaranty structural soundness.

  18. #38
    Join Date
    Feb 2006
    Posts
    1187
    Hey Unabiker you still alive? Ya tease us with your beautiful work and then vanish. How about a nod or somethin'

  19. #39
    Join Date
    Sep 2005
    Posts
    86
    Hey all,
    Sorry it's been so long since the last update. Went through a nice busy stretch, which meant my web surfing time had to be translated into workin' time.
    The shaker has been happily chuggin away for 6-10 hours a day, about every day.
    I had some welds fail on the cradle a while back. The welds were on the ribs of the cradle, on the back side. Too much force going through a section that was not supported enough. I fixed it by welding it where it broke and added some more reinforcement to make the whole cradle more rigid.
    At the same time, I added some thin plywood shims between the cradle and barrel. This was to make the fit between the two more snug. I could see where the cradle was not shaking at the same rate as the barrel in some places. This is lost energy to the media, more noise created, and also tough on the barrel as it tends to pull the barrel to cradle bolts through the plastic of the barrel.
    I did both of these mods at the same time, since I had to take the barrel out to fix the cradle. The net effect made the machine a bit quieter and made the media more active.
    I also changed the way I attach the weights to the axle. I was using 3 M6 bolts per weight that would thread into tapped holes in the axle. This resulted in a broken M6 or three about every 4 weeks. Its a real pain in the ass to take the axle out, then dig out a few broken bolt. The weights are .500" wall thickness aluminum tube. Pleny of meat to tap 10mm bolt holes. So now each weight is held in place by 3 10mm bolts that thread through the weight and clamp onto the axle. This makes the phase infintaley adjustable. Really a worthless feature in this application. I want the barrel and cradle to jump straight up and down. Any twisting in the jump only provides more wear on the guides, and less action in the media. It would be very easy to cut the weights in half, though, and allow adjustment to the amount of force the weights generate.
    I've found the easiest way to affect the flow of the media through the tub is to restrict the movement of one side of the cradle. I've been using a ratchet strap for this. The media is wierd. Some days, it tumbles in a nice top to bottome circular fashion. Other days, it just kind of sits there. When it sits there, we change the tension on the strap. It doesn't seem to matter if you add or subtract tension...it just needs to be different.
    The other major improvement is in the juice circulation department. After buring up several cheapo $10 pumps, I splurged on a $50 sump pump from Harbor Freight. This pump has a float switch, giving me control over the amount of juice in the barrel. The cheap pumps just could not handle the sediment. They would clog up, then burn up. The sump pump doen't seem to care about the sediment. I'm also using a router speed controller to slow the pump down.
    I'm now using a 20 gallon keg tub (leftover from a kegger) as the resivoir, which allows enough room for the float to work. The juice gets changed every 2-3 days. So far, the best finish in the least time seems to come from plain old tap water. The soap only seems to add time to the finish, and if you get too much, it leaves chemical burn spots on the aluminum.
    I'll try to get some pics the next time I have the sound-resistant box off of the shaker.

  20. #40
    Join Date
    Nov 2005
    Posts
    160
    I'm thinking about building a similar tumbler. I'm thinking about using some extruded alu channel for the 4 guide tracks and lining them with some teflon or delrin or something. Vibrating "cart" would have a matching teflon / delrin / whatever piece.

    I would think it'd make it a bit quieter then a loose metal on metal interface.

    I'm thinking a little smaller scale so I might just cut a 5 gallon drinking water jug in half or maybe take 3/8" of it out or something. Also only planning on doing final polishing so I thikn the thin wall will still last because its a very fine abrasive.

    I was looking at some commercial ones today and they seem to be much the same design anyways, at least for the large ones...

    Any thoughts?

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