Lego Pocket Whistle Keychain 3x6

A pocket whistle shaped like a classic toy building brick. The outside is a 3x6 brick in true stud dimensions, two plates tall (2/3 of a standard brick). The middle row has one stud fewer to make room for a key ring hole, so it works as a keychain.

The inside comes unchanged from the BETA Flat Pocket Whistle 5mm. The twin chambers, windways, mouthpiece and labium geometry are copied 1:1 and only the outer shell was redesigned, so it should sound like the original. The side windows are extended through the thicker brick walls and flare outward, so they don’t turn into a tunnel that could change the tone.

It’s a single part with no supports and no assembly. It prints flat with the studs facing up.

Features / Parameters

• Size: 23.8 x 47.8 x 8.2 mm (6.4 mm body + 1.8 mm studs)

• Real brick proportions: 8 mm stud pitch

• 17 studs, 5.05 mm in diameter (FDM-tuned so real bricks fit snugly on top), with the middle row shortened to leave space for the key ring hole

• Key ring hole: 5 mm diameter with chamfered edges and a 1.9 mm end bar

• 0.4 mm chamfer on the bottom and top edges, which hides elephant foot and the top-edge bulge

• All heights aligned to 0.2 mm layers (8-layer floor, 9-layer roof, 9-layer studs)

• Inner whistle cavity identical to the original (3.0 mm tall twin chambers)

• Solid bottom, so it does not snap onto real bricks, but bricks can be stacked on top of it

Print settings

• Orientation: flat on the bed, studs up (the STL is already oriented this way)

• Supports: none (the cavity ceiling is a short bridge, same as in the original)

• Layer height: 0.2 mm

• Nozzle: 0.4 mm

• Walls: 3

• Infill: 10 % gyroid

• Top/bottom layers: 5 / 5 (floor and roof come out fully solid)

• Brim: none

• Elephant foot compensation: 0 (the bottom chamfer already handles it)

• Top surface flow ratio: 0.95 recommended for crisp top edges

Tips

• Stud fit depends on your printer and filament. If bricks sit too loose or too tight on top, scale the model by 1-2 % in X/Y.

• Keep bridging speed and cooling at your usual settings. A clean cavity ceiling helps the sound.

• Clean any strings out of the side windows and the mouthpiece before testing.

Files

• lego_pocket_whistle.stl

Remix of BETA Flat Pocket Whistle 5mm. All credit for the whistle’s inner acoustic design goes to the original author.
Licensed under CC BY-SA 4.0, same as the original.
Not affiliated with, endorsed by or sponsored by the LEGO Group.

Tags
whistle, keychain, brick, pocket whistle, toy, gift, kids, emergency whistle, remix, no supports