M18x2.5 Nut Spinner

This is a small fidget hand spinner using M18 nut and MR105 bearing (5x10x3-4mm).

##Updates

• 2018-04-09: Added Dish_Button_Set.stl and Dish_Button_Set_PrimeTower.stl (requires supports)

##Features

• Screw-in system
  Adapters and buttons can fixing by printed screws.
  This makes it easier to remove/replace bearings

• Easy twistable button
  I designed the button hexagonally and made it easy to twist with fingers.

• Clear and smooth gyroscopic effect
  As a result of using a small bearing, the judder and noise emitted from the bearing when the spinner was tilted decreased less.
  This makes it possible to feel the gyroscopic effect clearly and smoothly.
  If you rolling spinner with your palm, the momentum of spin increases and gyroscopic effect also increases.

• Variability of bearing axis
  If you do not fix the bearings with tape, the bearings will move slightly each time you use the spinner.
  This leads to irregular changes in the gyroscopic effect.
  In short you can enjoy a small difference in gyroscopic effect every time.
  When using a lubricant in which oil and grease are mixed, the position of the bearing will not change so much, but the feel of spin will change due to the change in the hardness of the lubricating film depending on the temperature and conditions of use.

• Can continue spinning forever
  Spinning momentum is adding when you slap with the palm of your hand.

• Can be placed vertically (after spinning)
  When placed vertically, you can grab the button immediately when you use the spinner next time.

##Notes

• Filament
  I printed with PLA filament, but I have not tried it with ABS or other filaments.
  As ABS filaments may break if oil or grease adheres, care must be taken when printing with ABS filaments.

• Warp at the top of the adapter
  If warping is made in the screw part at the top of the adapter, it is good to sanding and flatten it.

• Grease life expecting gyro effect

  • White lithium grease: 1 week
  • Urea based grease: 3 months
  • Aluminum complex grease: ?
    I have not tried it yet, but I think same life as urea based grease.
    If you are concerned about the smell, you may want to use food grade grease.

• Black oxide steel nut

  • How to convert red rust(Fe2O3) to black rust(Fe3O4)
    1. Added vinegar to tomato ketchup and apply it to the steel nut
    2. After red and black rust disappeared, wash the steel nut with soap
    3. Immerse steel nuts in dense black tea (using soft water as much as possible)
  • Surface coating
    Red rust and scratches can be prevented by painting the surface.
    Black rust is porous so paint is easy to settle.

##Requirements

• 1 x M18x2.5 metric hex nut
  • Width across corners: 29.56mm
  • Width across flats: 27mm
  • Height: 15mm
  • Weight: 45-46grams (steel nut)
  • Thread pitch: 2.5mm (coarse thread)
  • Fastener thread direction: right hand
• 1 x MR105 bearing (also known as 1050 bearing)
  • Inner diameter: 5mm
  • Outer diameter: 10mm
  • Width: 3-4mm
    • 3-4mm things are mainly used for radio controlled cars
    • 4mm thing is same as size-A of yo-yo.
• 1 x Adhesive tape (not an absolute requirement)
  • Reduce backlash between adapter and bearing
  • If wobble occurs when spinning, adjust the bearing position without tape
  • If there is a gap between the external thread and the bearing, it may be better to stick adhesive tape to the base of the external thread to fill the gap
• 1 x Coin
  • Thickness: around 1.5mm
    • Used to screw-in adapter

##Print Settings

• Resolution: 0.2mm
• Infill: 90%
• Rafts: Yes
• Supports: No
• Supports(Dish_Button_Set.stl and Dish_Button_Set_PrimeTower.stl): Yes