Redstone · Mechanisms · 1.21

How to Make a Piston

The block that makes blocks move. Give a piston a redstone signal and it shoves whatever is in front of it, the heart of doors, traps and flying machines.

Flip the lever below to fire it.

The recipe

Planks on top, cobblestone around an iron ingot, redstone dust at the bottom.

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Grab the grid on Astroworld crafting or look up the piston.

The sticky upgrade

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Add a slime ball to the face and you get a sticky piston: it drags the block back on retract instead of dropping it. Essential for doors and flying machines.

What it can and cannot push

It pushes

✓Most solid blocks, up to twelve in a row at once

✓Players, mobs and dropped items in the way

✓Itself sideways or up, the trick behind flying machines

✓A sticky piston also pulls the block back on retract

It cannot

✗Obsidian, bedrock and other immovable blocks

✗Block-entities like chests, furnaces and hoppers

✗Anything with a block already blocking the arm's path

✗More than twelve blocks, the piston just will not fire

What to build with it

Hidden doors

Pistons pull a wall of blocks aside on a button press, then seal it again. The classic base entrance.

Flying machines

A pair of sticky pistons leapfrog each other to drag a platform across the world, no rails needed.

Traps

A floor that retracts, or a wall of blocks that crushes inward, all triggered by a hidden plate.

Auto farms

Pistons break or harvest crops, push mobs into kill zones, or toggle water flows on a clock.

Quick answers

What is the recipe?

Three planks on top, then cobblestone with an iron ingot in the centre, then cobblestone with redstone dust in the bottom-centre.

What is a sticky piston?

A piston with a slime ball on its face. It grabs the block it pushed and pulls it back when it retracts, instead of leaving it behind.

How many blocks can it push?

Up to twelve at once. Add a thirteenth in the line and the piston will not extend at all.

Why won't my piston move a chest?

Block-entities, chests, furnaces, hoppers, brewing stands, cannot be pushed. Neither can obsidian or bedrock.

How do I power it?

Any redstone signal touching it, a lever, button, redstone torch, pressure plate or a line of dust. Remove the signal and it retracts.

Honey block or slime block?

Both stick to neighbours and get dragged along, which is how big flying machines and elevators hold together.

Power it from a redstone contraptionlook up the piston, slime ball and redstone in the items database, or open the crafting recipes for the exact grid.

Push limits and the sticky version

Twelve blocks is the hard limit

A piston will not move more than twelve blocks at once, and it fails silently rather than moving eleven of them. Most doors that stop working when a build gets bigger are hitting this limit, not a wiring fault, so count the blocks in the column before you rewire.

Some blocks cannot be pushed at all

Obsidian, chests, furnaces and anything with an inventory refuse to move, and slime and honey blocks drag their neighbours along. Knowing which is which is most of piston building: a door that jams usually has one immovable block hidden in the wall it is trying to push.

Sticky pistons pull back, with one exception

A sticky piston retrieves the block it pushed, unless the pulse was so short that the head retracts before the block attaches, which is the block dropping trick that half of redstone relies on. If your sticky piston keeps leaving blocks behind, lengthen the pulse with a repeater.