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Oscillating Cylinder Motor for LEGO

Creation's quality: 5.0/5 (2 votes)
Evaluation of members on the printability, utility, level of detail, etc.

3D model description

You can see it in action here on Youtube.

Work animation in 3d viewer (Sketchfab):

Can be printed with 0.6 (or smaller) nozzle, at 0.2 layer height.
Takes about 7 hours (and 14m of filament) to print at 20mm/s.

Way more leaky than the Radial Motor , but looks a bit cooler, with all the moving parts exposed. Runs for about 15 seconds on a double wall balloon (one balloon inserted into another). Can run on a single balloon as well, just needs a lip from the 2nd balloon for the sealing.

Extra parts needed:

  • Nitrile or PET glove fingers for the membranes
  • Bolts: M3x6 x9, M3x8(or 10) x2, m3x14 x2, m3x10(or longer) x2, m3x26 x1
  • M3 nuts x4
  • Two air balloons


Will add an assembly video a bit later, for now you can
use this demo in 3d viewer as a guide.

  • Cut a finger tip off a glove
  • Put in onto a 4_3_Cylinder_Ring part
  • Insert the 4_1_Piston into the 2_1_Cylinder_L_Front, it should move freely
  • Put the 4_2_Piston_Washer onto the piston end
  • Put the 2nd washer, so the glove finger tip would be fixed between the washers
  • Insert the Cylinder Ring into the Cylinder, remove the slack from the glove finger
  • Attach the 2_2_Cylinder_L_Back with 3 M3x6 bolts
  • File down the flat part (with intake holes) of the assembled cylinder to remove the seam and layer lines
  • File down a little bit the flat parts (with air holes) of the 1_1_Base
  • Insert the 1_3_Axle_Pin into the 1_1_Base
  • Use the model in 3d viewer as a guide for the remaining parts
  • After the assembly, press the cylinders towards the base with the bolts at the sides - there shouldn't be too much friction between the cylinder and the base
  • You may use some lube on the piston and the other rubbing parts

Z_Plate_ALL_PARTS.stl, as the name suggests, contains all the parts on one plate.

Parts with X_ in their names are optional - you may assemble one-cylinder motor using the X_3_1_OneCylinder_Lid part, or a motor with single-acting cylinders using ..._HalfCylinder parts. The second one works quite poorly even on 2-walled balloon, but runs for almost 30 seconds and makes a cooler sound.

3D printing settings

Cylinders may print prettier with supports. Will print just fine without them as well.
Printed in Bestfilament PLA at 0.2 layer height, 0.6 nozzle.

3D printer file information

  • 3D design format: STL Folder details Close
    • 1_1_Base.stl
    • 1_2_Base_Frame_2Cylinder.stl
    • 1_3_Axle_Pin.stl
    • 2_1_Cylinder_L_Front.stl
    • 2_2_Cylinder_L_Back.stl
    • 3_1_Cylinder_R_Front.stl
    • 3_2_Cylinder_R_Back.stl
    • 4_1_Piston_x2.stl
    • 4_2_Piston_Washer_x4.stl
    • 4_3_Cylinder_Ring_X2.stl
    • 5_1_Flywheel.stl
    • 5_2_Crank_Right.stl
    • 5_3_Gear_32T.stl
    • 6_1_Balloon_Key.stl
    • 6_2_Balloon_Key_Clip.stl
    • X_1_1_Base_Bigger.stl
    • X_1_1_Base_HalfCylinder.stl
    • X_1_2_Base_Frame_OneCylinder.stl
    • X_2_1_Cylinder_L_Front_HalfCylinder.stl
    • X_3_1_OneCylinder_Lid.stl
    • X_5_1_Flywheel_Deco.stl
    • X_5_1_Flywheel_Heavy.stl
    • X_5_2_Crank_Right_Gear.stl
    • X_5_3_Spur_Gear_16T.stl
    • Z_Plate_ALL_PARTS.stl
  • Last update: 2021/03/13 at 12:25
  • Publication date: 2021/03/07 at 01:56





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