Mob Grinder Tower
A stone tower on four legs with a pitch-dark 18x18 spawn floor at the top, water channels that sweep everything into a central 2x2 shaft, and a 19-block drop onto a hopper pad wired straight to a chest. Every zombie, skeleton and creeper that spawns up there arrives at the bottom on two hearts, ready for a single swing, so you collect the experience as well as the loot. Bones, arrows, gunpowder, string and enough rotten flesh to keep a composter busy, all from one build and one water bucket.
What you need
| Block | Count |
|---|---|
| Stone bricks | 1084 |
| Stone bricks slab | 732 |
| Deepslate bricks | 354 |
| Deepslate bricks slab | 48 |
| Water | 8 |
| Hopper | 6 |
| Dropper | 2 |
| Lantern | 2 |
Counts are exact for the model above. Mine a little spare — nobody places every block first time.
Building it
Each stage names the layers it covers. Drag the slider on the model to that layer and you are looking at exactly what the stage describes.
1.Collection room and the hopper line
Lay a 20x20 apron of stone brick slabs at y=0 first: the tower's shadow keeps that ground dark, and anything spawning down there is a mob that did not spawn upstairs. Then shell an 8x8 deepslate room, and inside it raise a 4x4 wall ring at x10-13, z10-13 two blocks high with the middle hollowed out. That 2x2 pit is the landing zone. Its floor and the two blocks north of it are hoppers, all facing north: [12,0,12] into [12,0,11] into [12,0,10] into the double chest at [11,0,9] and [12,0,9]. Break out [10,1,11] and [10,1,12] for a knee-high kill window, and stand at x=9 to swing through it. Two lanterns keep the room itself lit and unspawnable.
2.Legs, shaft and the slab cap
Cap the collection room with deepslate slabs at y=5. That roof is otherwise a flat, dark 8x8 platform that would spawn mobs you never collect, and slabs refuse to host a spawn. Four corner legs climb from the apron to y=18 at (3,3), (20,3), (3,20) and (20,20), but the real load-bearer is the 4x4 stone brick column at x10-13, z10-13. Its 2x2 core is cut out in a single pass later, from y=4 all the way to y=20, so the shaft is one clean chimney from the platform straight down onto the hoppers. Deepslate bands at y=9 and y=14 break up the stack.
3.Spawn floor and water channels
Two solid 20x20 layers, at y=19 and y=20, make the platform. Cut a two-wide trench out of the upper layer along z=11-12 and along x=11-12, right across. The trench floor is the y=19 layer and the untouched pad blocks are its walls, so the water cannot spill onto the spawn floor. What is left is four 8x8 dry pads: 256 spawn tiles at light zero. Flood the trenches last, with sources at the four outer ends only, [3,20,11-12], [20,20,11-12], [11-12,20,3] and [11-12,20,20]. Each source pushes exactly seven blocks and stops on the lip of the shaft.
4.Walls, roof and darkness
A one-block wall at x=2, x=21, z=2 and z=21 rises to y=22 so nothing wanders off the edge, and the whole lid is stone brick bottom slabs at y=23. The slabs do two jobs: they seal the platform in permanent darkness so it spawns by day as well as by night, and nothing can spawn on the roof of the farm to eat into your mob cap. The gap between pad and roof is exactly two blocks, which is enough for zombies, skeletons, creepers and spiders and one block short of an enderman. That is deliberate.
5.Switching it on
Mobs spawn on the dark pads, blunder into a channel and get shoved over the lip. Nineteen blocks of free fall costs sixteen points of damage, so a ten-heart mob lands on two hearts and dies to one sword swing through the window at [10,1,11]. Drops land on the hopper pad and travel north into the chest. Nothing spawns within 24 blocks of a player and the platform sits only 20 blocks above the kill room, so dig a corridor twenty blocks out from the door and wait at the far end. This is not a hands-off farm: it needs you nearby to keep the chunks loaded, and you do the killing.
6.Trace the item path
Follow one bone from spawn to chest before you call it finished. Pad at y=21, into the trench at y=20, along the flow to the lip at x=10 or z=10, down the open 2x2 column through y=19, past y=4 and into the pit, dead on the hoppers at [11,0,11]. That hopper faces north into [11,0,10], which faces north into the chest at [11,0,9]. If any block in that column is still solid, or a single hopper points the wrong way, the mobs pile up or the loot sits on the floor.
Make it yours
- Count the channel out loud: one source block, then exactly seven flowing blocks to the lip of the shaft. Flowing water at level seven cannot spread again, so it stops dead at the edge instead of pouring down the shaft and cushioning the fall, yet it still shoves anything standing in it over the drop.
- Never wait in the kill room. Hostile mobs will not spawn within 24 blocks of you and the platform is only about 20 blocks above the chest, so standing there switches most of the farm off. Dig a corridor twenty blocks out from the door and idle at the far end, then walk back to collect.
- The fall is 19 blocks, which is 16 damage and leaves a zombie on two hearts, so one hit with any sword finishes it and you keep the experience. If you would rather it killed on landing, sink the collection room five blocks deeper when you build it for real: 24 blocks of fall kills outright, 23 leaves half a heart.
- Light and slab everything around the base. The tower throws a permanently dark 20x20 shadow, and any cave mouth within 128 blocks competes for the same mob cap. Lanterns belong in the collection room only, never in the shaft, or the light creeps up the chimney and thins out your spawns.
- The two droppers at [11,0,9] and [12,0,9] are standing in for a double chest, because this block palette has no chest model. Hoppers and water are drawn as full cubes as well: place real hoppers, facing north, and real water source blocks at those coordinates.
