Sreening Loam and Gravel

[bcarter]

I'd like to run this idea by the Tractorbynet brain trust to see what kind of thoughts that 60000+ person-years of experience can come up with on this project...

Any one out there ever built/used a screen to sift the rocks out of either loam or gravel? I've got some seriously boney gravel that I'd like to get most of the nuggets out of (with out resorting to hand work). In the future I'll have loam that I'll need to screen as well.

I've been thinking about using an old bed frame mounted with springs to a rigid box (built out of heavy marine plywood maybe). The frame would have a screen of 3/4" hardware cloth over it. Then I'd attach a small electric motor (dishwasher or washing machine) to the frame that turns an "off-center" weight to shake it. Based on what I've seen of a real screener, the frame should be on an angle so that the debris will roll off and the back side should be open so that I can scoop out the sifted material. I'd also guess that I'll need to weight the box so that it won't walk around...

I've got most of the materials already, so that cost isn't a huge factor. Just my labor (and as I've discovered, I work cheap /w3tcompact/icons/smile.gif)

Obviously I won't be using this for any production work but it would sure be handy to be able to screen materials without having the expence and hassle (mostly the hassle) of renting a screener. Anyone have any experiences with a project like this that they' d be willing to share.

Thanks in advance...


Bill

 

[RMulkey]

Bill,

I made a screen using a 4' x 8' x 2" tube steel frame with 1" angle iron for the field spaced 1" a part. The frame is tilted 30deg and stands 3' high on the low side of the frame. Works great. The rocks slide off the front and the dirt falls through. I think the key is to get the rocks to fall off without the operator needing to do anything. Sorry but I don't have any pictures. My dad liked it so much, he permanently borrowed it to his ranch in Nevada.

This apporach worked for me because I had steel available. The cost if you had to buy everything would be ~$200.

-Roger

 

[John_Mc]

I used to work for a company that sold the steel wire to companies that make "Aggregate Screen" This is th estuf that goes into the sifters used at quarries to sort out various sizes of rocks. It's a high wear item. I doubt the hardware cloth you propose using will hold up very well.

If there is a quarry in your area that does this sorting process, you might see if they will give/sell you some of their old screens. They are often thrown out when some of the wires in the mesh wear out (some places even replace them after a certain amount of use, even if they aren't broken yet). They are huge screens, so I'm sure you could cut out a good piece for your project.

BTW... these rock sifting operations are also a good source of rubber mats: We used to buy their old conveyor belts to put on our floors to protect our coils of steel wire and rod during storage. NOTE: mats are VERY heavy. A decent sized roll is more than a typical pickup truck can handle.

 

[njrqs]

Sounds great !

I have been using a hand sieve to get some topsoil for the lawn, leaving me with rocks.

I did enough to fill 1/2 my 6x4 trailer with rocks, giving me 4 barrows of topsoil !

Good excercise if nothing else !!

Neil R.

 

[ERNIEB]

I used to work for a company who used the aggregate screens made from the wire that John Mc sold.
It sounds to me like you have looked at a portable screen such as those made by Allis Chalmers, Power Screen, and others. I've had thoughts of making a minature version myself.
A friend of mine took an old dumpster, cut the back out, replaced the lid with a 1 inch screen, and uses it to screen the clods out of top soil. It was the type with the slanted lid,, so the screen is at a good angle. It works OK for small amounts of topsoil. But, like you I would want the screen to viberate.
Unless, you are planning to do hundreds of tons, I wouldn't worry about the wire wearing. Wire stretching, now that might cause a problem, it might cause the screen to sag.
I've been thinking about using something like the gear box on a shreader and running it off the tractor PTO. Mainly because I would have to put the thing way in the back where I don't have electrcity. I wonder if on an electric motor, you might need a reducer.
If you build it, let me know how it turns out. I'd really like to do the same thing, if I can ever find the time.

Ernie