Allans3d Trommel

A fully modular 3d printed trommel that can be adjusted to your needs.

The basic trommel has a number of bays (decided by yourself, one upwards) that are connected to a feed hopper with a spiral feed.

The spiral feed has a large clearance to the feed body in order to try and limit jams.

The whole unit is driven by a JGB37-555 motor gearbox rated at 500 RPM (approx) at 12 volts but run of e.g 6 v sealed lead acid, 2s lipo or 7.2v Nimh battery. For a 12 v battery then use 150-250 rpm.

**Update 12

With larger lumps I got some jams with the entry to the drums. Ive do 2 things:
1. Changed the hopper feed spiral to have 4 turns.
2. modified the drive ring to have two spokes that have chamfers .

Files are now available in the downloads.

**UPDATE11

corrected design for walkways.

Updated the drive ring to push the hub further into its body.

** UPDATE 10

This is a major update to the files. It follows feedback and requests from the community and addresses some problems with the original design.

The bays are now 274 wide and the basic support is now 150mm tall. There are also risers that can increase the height by 75 or 100mm. The risers have holes through them to allow wires to be added for more secrure location on softer ground.

This also means new barrels.

The join from the bays to the feed hopper is new and the motor housing is redesigned to fit more easily and allow longer belts to be used.

The drive ring is re-disigned with a retension ring and the feed hopper now extends into it. Feed spirals are updated as are walkways and railings.

corner and rear joiners for the base of the risers have been added to give high stability.

Construction is pretty much the same any problems contact me.

**

Update 9:

A problem with the feed hopper join has been reposrted in that the join leaves the motor housing at an angle. I have uploaded a single replacement file for the join as an interim connection.

Update 8:
I have added a file for an anti leak ring, this fits around the feeder assy output to prevent reverse leakage.

I have been asked for a set of parts that give a wider bunkers, these are now in a folder called "Wide Bunker". The files inclede new rear walls, new barrels, new walkway and new walkway railings. I have also added a 5mm barrel.

Update 7:

There was a problem with the 6mm barrel being too short. My original file was corrupt so I have regenerated all the barrels no with larger spiral sections and also now with 4,6,8,10 and 12mm holes. If you want a custom size then I can generate that easily now as the whole design for the barrel is parameter driven.

Update 6:
I believe that the feed spiral broke due to flex in the motor housing join. I have now replaced it with a solid version printed as a block and including the first bunker side wall. The assembly is now 200mm long so could be challenging on smaller printers. If you need it section the give me a message.

The new feed hopper join means that the motor housing needs to be replaced. the new design is part of the changes.

Lastly the feed hopper location is not so critical but moving it could mean the feed spiral would be too short, so we have provided longer versions in a range of sizes to suit your build.

Update 5 1/march 2025

I broke a feed spiral when it hjammed so I have strengthened the central hub from 5mm to 8mm. I have also provided a numer of different sizes of spiral from 30 blade to 35mm blade. These should cover most applications. Please message me if you want another size.

It was suggested that I provide the option for an ESC to control the speed. There is a cheap and small ESC on amazon and aliexpress most are 2 amp but there is a 10 amp version. I recommend the 10 amp version. I have released a version of the motor housing to cater for it. Its shaft is too short so it needs retaining with glue, I used CA but hot melt should work fine.
Update 4:
added file for optional output ring. This replaces the last bearing ring.

Update 3:
Replaced files for feed hopper, feed hopper top and feed hopper bottom.

added files for 34 and 36mm diameter feed spirals as I think the original was too small depending on what you are sorting.

Update 2:
corrected a typo in the instructions PDF. The bearings should be 5x13x4.

Update 1:
released the files for adding a walkway, this can be front or rear of the trommel.

Instructions remain the same but the files are now in a zip.

Thanks for your patience!