Thread: Making a motorised sieve/vibrator

https://youtu.be/eZsiBNibzI8

(don't use your Festool jigsaw though!)

https://youtu.be/eZsiBNibzI8

In the coal industry, big seives were in the form of large screened platforms, suspended by 4 cables.
Attached to a platform was a big gearbox with heavy, contra-rotating shafts. They were designed to shake violently in one plane, driven by electric motor.
Maybe, if it was worthwhile, you could rig up a similar arrangement with 2 separate out of balance shafts. It could prevent material from being ejected from the tray.

Jordan

Hi FenceFurniture, I don't like the chances of your motor lasting very long with all that shaking.

I reckon a better idea would be to fabricate a drum out of mesh, and either turn it similar to a concrete mixer, or sit the drum on 4 wheels/rollers on say a 30 degree angle, to keep the dirt from spilling out of the end.

Figuring out how to turn the drum should not be very difficult.

Ken

Thanks for your replies chaps. There's an idea brewing - a bit of a combo of the ideas presented.

• I've got an old Metabo hammer drill that doesn't owe me anything
• I dug up an old engine valve yesterday (buried for something like 50 years and in perfect nick) - the seat could be ground eccentrically, and the shaft is perfect to go into the drill chuck
• suspend the tray from ropes on a frame
• insert the drill and let 'er rip

Actually, just thinking on the run here, I wonder how the hammer action of the drill would go? Probably not enough vibration, but pretty easy to test......

Originally Posted by FenceFurniture

I think this is the right sub-forum for this bit if not it can be moved.

I want to make a motorised sieve/vibrator for sieving garden soil. I have a mulcher that has seen better days and I could nick the 1 (?) hp induction motor from that.

The idea that springs to mind is to attach an eccentric disc to the shaft of the motor, which would be inserted into a metal ring (perhaps a bearing race) set in the side of a sieve tray. The tray would have to be mounted on springs to account for the motion.

It would be best if the tray was easily removed for removing the sieved out stones/roots etc. Perhaps four clips to hold it in position.

For the tray itself it would be best if it were metal sided for strength, but maybe I can get away with timber with some decent sized screw holding it together. The sieve would be 10-15mm mesh.

What does the brains trust think please?

Hi FF,
Don't know if they can still be found, but the old style spring base, with the coil type wire and angle frame, make an excellent sieve. The wire is about the right size for what you want. As someone suggested, suspending it from cables will be the easiest way. To make it vibrate, a disc approx 150 diameter mounted to the motor and an arm with ball joint ends, similar to a steering arm mounted onto the disc and the suspended base. The disc could have several holes or a slot in it to give various amounts of oscillation. The base already has holes in it to bolt to the eye of the cables, or use "D" shackles to mount them. I wouldn't use rope, as I think they wont last to long, OK for trying idea.
Kryn

Heh heh, funny you should mention a bed Kryn. There happens to be a metal frame one down the back - forms part of the "fence". Trouble is the wire base is such that a piece of 4x2 could just about go through it (even though it's in 100% condition). Actually I've long been pondering how I could employ that for the task.

I spose I could just secure some smaller dia mesh to it......

The idea of the wobble disc sounds good - and easy enough.

I'm thinking you mean a disc sort of similar to this (which is for the rise and fall of my thicky table - mounts in a battery drill). Just add some knobs or whatever near the edge.

Yeah something like that, as long as it's strong enough. I wouldn't use MDF though as I don't think it would last to long. That bed frame could be used, just a matter of getting the mesh small enough, which was why I suggested the older type wire mesh. Actually from memory, I think they were on a wooden frame, both ends were nailed on, one fixed and the other tensioned up using 2 about 5/8" bolts 10" long from memory. Usually they're hollow in the middle where peoples weight has stretched the coils. Fun part would be trying to find one now. One of these was my bed for a number of years.
I was getting mixed up with the later style that used coiled springs, silly me.
If you're going to power it with a drill, rope would probably work OK, as long as it wouldn't be going too fast. Fun part would be making a mount for the drill, a block of wood and a couple of hose clamps will probably do the job.
Saw another version on ABC Gardening show, where 2 bike rims were used, sitting on 4 castors with the outside of the rim running on the castors. Several layers of 1/2" square mesh were inside the rim and bolted/riveted/zip tied together about 900 apart and 150 mm slope. Rotated by hand.
Kryn

I once needed a vibrating table for something I was doing. I bolted a spare .75kw motor to the table then used a pair of hose clamps to attach a piece of 20mm round to the side of the motor shaft. Quick and effective.

I made what you are asking about many years ago. It was a frame of 2 x 4 pine with mesh on the bottom and I think it slid on another pine frame. The drive was a washing machine motor. I drilled holes in the centre of 2 pieces of round steel to suit motor shaft and pivot bolt. These were welded together slightly offset, maybe 6mm or less. This was so the welds could be cut and the offset changed. This was before I had any but basic metal work tools. The motor was connected to the frame via a bit of flat steel. I only used plain bolts for pivots. The whole lot sat on top of a wheelbarrow.

It was only for one job of cleaning sand or gravel, but it worked. The addition of bearings would improve the life of it if you wanted to use it for a longer period.

Dean

If you have a shooter friend, ask him can you look at his cartridge case cleaner, its a plastic pot with some kind of medium in it, empty cases go in, turn it on and it vibrates. cases come out like new. Its the mechnism that i am suggesting you look at to see what makes it vibrate, maybe you can adapt that to a larger scale.

I would go with the Trommel idea though as one has already suggested. Drum made out of mesh with holes, elvated and rotated. Seen some big buggers working seperating ore from waste.

DD

Cartridge cleaners use an offset weight on the motor shaft to provide the vibration. The container and motor is mounted on springs.

Dean

According to our Metallurgy teacher, its also called a "riddle" so if you search on "riddle sieve' you might find some more info

bollie7