Pneumatic Engine

Here is a pneumatic engine I made in my free time a while ago, I plan on 3d printing it, however at the moment my school's 3D printer is broken.

External Parts Required:
- 6 M2.5 Bolts (17mm long)
- 2 M2.5 Bolts (27mm long)
- 1 Bearing (11mm Outside Diameter, 5mm Inside Diameter, 5mm Width): https://www.amazon.com/gp/product/B07FW26QBV/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
- 1 O-ring (8mm Outside Diameter, 4mm Inside Diameter, 2mm Width): https://www.amazon.com/gp/product/B07F37KYZZ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
- 1 Bearing Ball (6mm Diameter): https://www.amazon.com/gp/product/B07DKSN46T/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
- 1 Pen Spring (Any should work fine)