Thought I'd share my Mob Grinder design for those who are interested in building their own or even wish to copy mine. I designed this myself (Or at least came across this idea if its already been established) after watching a few videos on Youtube.
Basic things needed: Buckets of Water, Cobblestone, Cobblestone Halfslabs, Ladders, Buckets of Lava (Two will do in most circumstances), and Torches so you can see.
How it works: Four different 5x5 pads (25 or 5x5 Cobblestone Blocks with a Cobblestone Halfslab every two blocks) are seperated by water canals two blocks deep on each side, effectively making each layer (Excluding the Lava Blade section) a 12x12x5 area. The water canals on the layers above the layer containing the Lava Blade and item collection area use ladders to stop its flow from exiting the flat area. The bottom layer only uses ladders on the canal that is directly above the Lava Blade, the other three canals are allowed to flow so as to push the monsters into the Lava Blade. A small tunnel is dug beneath the Lava Blade ladder and a large system of ladders allows you to enter the tunnel and walk beneath the Grinder to collect the drops.
Important Potential Design Oversights:
-Ladders are used to block ALL of the canals from flowing below the layer they are on. The exception would be the 3 canals on the bottom layer that are not above the Lava Blade. (See picture 3)
-The canals have two raised blocks at the beginning to help when building (The canals are two blocks below the pad, the first blocks being 1 block below the pad) and I found it generally helps with how the water moves. (See pictures 1 and 2)
-The canals drop off to the layers below one block before the end of the pad making the pads corner extend one block past the canals path. The ladders for blocking the flow are placed on the corners of the blocks below the pads. (See pictures 1 and 2)
NOTE: only the top layer of my Grinder is above ground, the other two are below ground. I have noticed that more Mobs tend to spawn in above ground Grinders then below ground. Logically, I'm guessing this is because in the air there is nowhere else they can spawn besides inside the actual grinder (Considering you put torches on top of it like I do). Verses underground; there are potentially caves and other dark areas for the Mobs to spawn in besides your trap.
A view of the grinders 3 layers from a hole in the roof.
All four pads and the water canals inside the top layer of my grinder. Note that there are only two blocks between the pad and ceiling.
A view of the end of the water canals from the bottom layer that run into the Lava Blade trap.
Nice. I usually build similar, except I use 8x8 pads and I alternate the canals to avoid fall damage.
Layer 1 has canals that go inward to the hole to the next layer.
Layer 2 has canals that go from the center to outside.
Layer 1 has canals that go in.
<etc>
On the current version, there's really no reason to do this since you won't be building an XP farm and your design is to kill them ASAP.
I have a couple of the pistonless+waterless versions working on the 360, too.
Basic things needed: Buckets of Water, Cobblestone, Cobblestone Halfslabs, Ladders, Buckets of Lava (Two will do in most circumstances), and Torches so you can see.
How it works: Four different 5x5 pads (25 or 5x5 Cobblestone Blocks with a Cobblestone Halfslab every two blocks) are seperated by water canals two blocks deep on each side, effectively making each layer (Excluding the Lava Blade section) a 12x12x5 area. The water canals on the layers above the layer containing the Lava Blade and item collection area use ladders to stop its flow from exiting the flat area. The bottom layer only uses ladders on the canal that is directly above the Lava Blade, the other three canals are allowed to flow so as to push the monsters into the Lava Blade. A small tunnel is dug beneath the Lava Blade ladder and a large system of ladders allows you to enter the tunnel and walk beneath the Grinder to collect the drops.
Important Potential Design Oversights:
-Ladders are used to block ALL of the canals from flowing below the layer they are on. The exception would be the 3 canals on the bottom layer that are not above the Lava Blade. (See picture 3)
-The canals have two raised blocks at the beginning to help when building (The canals are two blocks below the pad, the first blocks being 1 block below the pad) and I found it generally helps with how the water moves. (See pictures 1 and 2)
-The canals drop off to the layers below one block before the end of the pad making the pads corner extend one block past the canals path. The ladders for blocking the flow are placed on the corners of the blocks below the pads. (See pictures 1 and 2)
NOTE: only the top layer of my Grinder is above ground, the other two are below ground. I have noticed that more Mobs tend to spawn in above ground Grinders then below ground. Logically, I'm guessing this is because in the air there is nowhere else they can spawn besides inside the actual grinder (Considering you put torches on top of it like I do). Verses underground; there are potentially caves and other dark areas for the Mobs to spawn in besides your trap.
A view of the grinders 3 layers from a hole in the roof.
All four pads and the water canals inside the top layer of my grinder. Note that there are only two blocks between the pad and ceiling.
A view of the end of the water canals from the bottom layer that run into the Lava Blade trap.
Layer 1 has canals that go inward to the hole to the next layer.
Layer 2 has canals that go from the center to outside.
Layer 1 has canals that go in.
<etc>
On the current version, there's really no reason to do this since you won't be building an XP farm and your design is to kill them ASAP.
I have a couple of the pistonless+waterless versions working on the 360, too.
It handles spiders too.
If it dies it will be your fault... SO CLICK IT!