View Full Version : Homemade parts tumbler
04-08-2008, 06:44 AM
I need to tumble parts which require it to be made out of a piece of pipe 18"x 36"long. What I need to know is the sproket size, on both the tumbler and the engine as well as the chain size. The tumbler will be powered by a small gas engine so rpm's will be adjustable. Any help will be greatly appreciated.
I had this that I was going to post some where else so I'll just trow it up. Sorry if its a little long.
I have built several rotary tumblers for a couple of people. This is my current one. Not as pretty and finished as my last couple, but I made it out of misc. parts I had in order to do a rush job after I sold my old one.
I use it both for cleaning tanks, you'll see one in the pict. and also for parts, my buddy has my parts drum right now.
The drive unit is a parallel shaft gear motor. I get it from grangers. I have found the 30 rpm ones seem to work well. I had a 18 rpm one and it worked but took longer. I may try to get a set of 60 rpm gears to put in mine just to see if its any better when I have some spare change. You don’t want it to spin to fast or centrifugal force will force the tumbling media to the sides and carry it over the top. You want it to rise and fall. I have seen them made from motors with a gear and chain drive, Belts often slip under the torque. These motor rpms are based on an 8" tank, a larger dia will require a faster motor speed to get # of rpms on the drum that you want.
The motor is connected to the drive roller by a Love joy connection. Mine is a L-075 but I usually go with L-095 or L-100’s You need to go with urethane or hytrel spiders as the buna ones fail rater quickly 20-48 hrs run time under load. This allows for shock take up and alignment problems. The center drive shaft is ¾” cold rolled in 2 pillow blocks. I have used flange bearings but if the bolts/nuts protrude in to the center area you will slowly machine your drum. My drive roller uses a poured urethane roller. I had the urethane from another project and this does not mark tanks like other things I have tried. For a parts tumbler I would use boat trailer rollers. The rollers must be a very tight press fit on to the shaft. The one I build for my buddy we had to drill out the rollers and then pressed them on with the shop press. If the roller slips it will not work.
The side idler rollers on mine are bearing mounted. I had some material rollers that I encased in urethane and just left the PVC forms on to give it more diameter. Normally I use 3” PVC for the forms but I was running low so its 2”. No big deal. My buddies is made from boat rollers. These were drilled slightly oversized so the are a slip fit on the shaft. shaft is well greased and rollers are slid on. The motions for this are very sexually suggestive so I leave it to your imagination. Stops at each end allow some end play and keep them from walking. My last one used a 1 pc poured idler rollers and I inserted a counter sunk grease fitting. Not as good as I hoped. The fitting would allow you to grease the roller from the center with out removing, greasing, siding it on and off and repeating several times until done, however it tended to pull out of the urethane when you tried to remove the grease gun.
Shaft size on the idler is important. The original ones I copied had ½’ shafts. Bent. My first set had 5/8” shafts. These were so so. I now go with ¾” min for all the shafts. The ones in the picts are 5/8” threaded rod but the bearing mounted material roller and PVC make up the difference. I usually thread the ends of the round stock to take nuts on both sides to lock it together. You could use pillow blocks or flange bearings but I find the costs prohibitive. I have also thought about using casters, inverted as the idlers, again I have found it cost prohibitive for my purposes.
Frame work is 3/8” steel plate with c channel for the motor on one side, 2x3” angle on the far side. The nuts on the threaded rod lock it together and allow me to adjust for tanks of various dia. You would need a bottom frame if you were to use bearings on idlers. Top frames tend to get in the way of loading unloading the tumbler.
I wire the cord to either a utility box with a standard switch or a timer.
My parts drum is made of 12” dia pipe plated on one end. The second end is removable. I’ve have tried several options a ring welded to the other end with a bolt on door seams to work ok. My buddy has had some luck with 8” pvc pipe with a cap on one end and a threaded male/ female set up on the other. He often wet tumbles and I haven’t quit got an o-ring to stay and seal mine. Need to cut a grove in the lid. % gal buckets may work if they will roll well haven’t tried. A 30 gal drum with a removable top is perfect but very large and heavy. BTW the tanks on the tumbler can weigh as much 60+ Lbs empty, plus tumbling media about 50 Lbs for the large ones plus several gal of water to fill to the top. My guess both tanks on at once 230-250 lbs total load,
I use alum oxide tumbling media from advanced deburring mostly. Also have glass beads and ceramic chips. I have also seen coarse sand used, small screenings used and even ¾” stone. The stone was used in a concrete mixer to clean parts runs in a fab shop.
Any questions fell free to email or pm me and I'll be glad to help.
04-08-2008, 09:56 AM
It depends on the weight and composition of the parts to be tumbled, but "slow" if usually good enough. If you intened to debur parts, you may want to add some sort of media (beads, balls, or whatever) to aid with that.
You can't get a firm gear ratio w/o knowing the intended purpose, and the speed of one or the other, and preferably both the motor and tumbler. It could require a good amount of torque to turn that size of tumbler w/ heavy contents. You should choose a power source that is "rated" for the proper amount of torque at the desired RPM.
As an example for your application of the sizes given, if you were to "idle" a small gas engine at about 800 rpm (most gas engines won't run much slower and/or have any torque) and if you wanted the tumbler to turn at 20rpm (40-1 ratio), you'd need to use a 10 tooth sprocket on the motor and a 400 tooth on the tumbler. Not too practical. Have you ever seen the inside of a clothes dryer and the motor-to-drum/belt ratio?
Forget the sprockets and use a belt, it's cheaper and easier. I would just use the drum for the large pulley and the smallest pulley for the motor I could get on it. A 2" pulley (motor) and the 18" drum would be 9-1 ratio. Considering these sizes, to get 20rpm you'd need the motor to turn 180rpm. You would still need to use a compound reduction drive system (jackshaft) to slow things down more. A high torque, variable speed electric motor would be the best solution, but it is also the most expensive.
Better yet, do what DSW said and buy the best gearmotor for your application.
04-08-2008, 12:56 PM
Nice post. I have never had to clean my tanks yet. Hope I don't have to anytime soon.
It gets pricey just doing annuals and hydros. I am a PADI REC-TEC certified gas blender.
Air, helium, oxygen...you know.
Great thread troye. Gave me neat ideas!
Joker11 As long as you use alum tanks and don't partial pressure blend you won't need to clean. (since you are a blender I assume you know this. The comment is for others) Steel tanks require more frequent cleaning if the shop dosen't follow good fill practices.
I clean my tanks with every hydro, inc. valve rebuilds. I have a group of technical divers including several employees and instructors of other shops who have me clean their tanks. Many just don't trust their own shop to do it right. Several have me clean their tanks when they come back from N. Carolina, some of those tanks get pretty nasty fills down there. I used to clean Richie Kohlers tanks every year. Great guy, I'm glad he is getting to live his dream and work his dream job. Unfortunately I don't get to talk to him much anymore, as he globe trots around the world.
troye: Thank you, You got me to go ahead and post on the other forum.
Here's a pdf that someone there found that is somewhat similar to mine in basics but uses a motor and belt. It also has some interesting ideas on speed calcs.
Thinking a little more, if you combine my center drive idea with the motor and drive pulley suggestions that Rick posted, you may be able to get the rmp that you may need. 800rpm motor w 2" pulley to 8" pulley on center roller = 200 rmp if I understand Rick's post. Then 2" center shaft outside dia to 18" drum would give you 22rpm if I understand correctly.
BTW thanks Rick, pulleys and gears always leave me a little baffled. I understand the concepts, its the execution that eludes me sometimes.
On the tumbler subject but slightly different. I have a friend with a fab shop and what he uses to debur bulk parts that he plasma cuts prior to assembly’s a gas powered commercial concrete mixer that he got from when his brother went to an auction. He uses 3/8" crushed stone to clean the parts as a tumbling media for smaller parts and 3/4" for larger parts. Sand would work also for very small parts. Noisy as all get out, it runs outside. A little large for the average person but does a wonderful job.
Someone posted this on the other site, at the cost of this it's almost not worth building one if you only use it infrequently.
Look around for an old cement mixer. Use a smaller pully on the motor to slow it down a little more and cut the paddles out of the drum and you should be good to go.
04-09-2008, 02:58 AM
DSW, Ok, let me clarify.....My EANxx tanks were delivered cleaned. I do partial pressure blending in only those tanks. To be honest....when I get premixed EANxx I use only those tanks as well. At any rate they are O2 clean. Yep yep. Thanks. Do you use simple green?
Sorry guys. I hijacked the thread again. My bad.
If I need to tumble my tanks I will have to build one of those bad boy tumblers because that is one great idea!
Joker11 Yes I use simple green most of the time. It washes out easier. Dawn works well also and I use it as a first wash on super nasty tanks. If you get ready to do your tanks in the future pm or email me and I'll give you how I do it. I have a few tricks that I've picked up that will help. I also have an awsome SS drying stand that I'll show you if I can steal back the digital camera so I can take some shots. It's about the 4th or 5th revision and really works well. I also have some info on tumbling media that I use on steel tanks as well as alums occasionally.
I also have parts lists for most valves for rebuilds if you need them.
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