Custom Sapphire Gear

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Jun 24, 2014
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I started building some gear a while ago. Nearly got the trommel done. The aim is to have the trommel wash run through a jig (still yet to be built) and the whole thing will be mounted on a trailer.

Only cost me around $400 so far for someone to role up the cylinder, make the octogon frames and buy bearings for the rollers. Materials are from whats just laying around at home from other projects.

Frame: Octagon shape adds strength and serves a s a great spot to mount some sheilding and the rollers.
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Rollers are the tricky part. I have a tendancy to massivly over engineer things. But the idea is to build something that lasts forever and can be maintained as well. The last thing I want it to have to drive 18 hours round trip to replace a broken part. The rollers have twin bearings and can be easily disassembled for maintenance.

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2 bearings
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Dissasembled with just 2 bolts and 2 grub screws
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A common problem is drum creep. Especially when the machine tilt is adjusted. Simple physics. The first idea was to make the collars a channel but the problem with this is it puts side loading on the bearings and will wear heavily on the up side edge of the roller. Easiest way to fix this is to add a fifth roller and a lip on the end of the drum.

Barrel creep after just a few turns. Tilts is 20 degrees
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Lip in place
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Roughly were the fifth roller will be. Still need to build a section of the frame to hold it in place.
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Haven't worked that out yet. Depends on how big I make the jig I guess. Also I'm planning to make several screens for it so I can swap em out depending on the ground.
 
Yeah its definitely got a bit of weight to it. It's easy enough to move piece by piece but that's a bit of a pain. I'm aiming to build a small off road trailer to mount the gear on permanently. Kind of like a mobile mining rig.
 
Haven't decided yet. I'm leaning towards an electric motor and a geny. The geny can be used for the campsite at night.

Also more grunt for less weight as the motor will have to run the jig and trommel together. If I install a soft start i think i should be able to get away with a standard .75kw motor. Lucky i have a few lying around to try with.

At this point i am looking at a twin belt around the cylinder but if i can find a way to run a chain that would be better.

Decisions, decisions!
 
geez there are some fine engineers on here

put me to shame.

My old man could turn his hand to anything wishing now I had inherited theright jeans 8.(
 
SneakyCuttlefish said:
Haven't decided yet. I'm leaning towards an electric motor and a geny. The geny can be used for the campsite at night.

Also more grunt for less weight as the motor will have to run the jig and trommel together. If I install a soft start i think i should be able to get away with a standard .75kw motor. Lucky i have a few lying around to try with.

At this point i am looking at a twin belt around the cylinder but if i can find a way to run a chain that would be better.

Decisions, decisions!

I think V belts will probably work better, if you install a couple of guides on the drum they won't try to jump over each other, you can use a roller tensioner and dust won't worry the belts too much. Chain on the other hand you are dealing with lubrication, dust ingress into the chain, sprockets etc and zero slip, so if anything jambs up there is no give until it breaks or the motor burns out unless you have overload protection. The third alternative would be a flat drive belt, something like the ones F & D O'Connor supply, simple and reliable dust won't pose a problem and will slip for protection. Probably my preference.
 
Thanks dihusky. Thats the plan! Just need to build a frame, install the spray bars, motor and pump and build a jig to go under it.

Thinking about mounting it in a trailer for easy carting too but i cant find a decent 2nd hand trailer i can strip down. Didnt really want to build one from scratch but i may have to.
 
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