Filament spool

Yes, another filament spool !

Advantages of this design are :
- Large 100mm center preventing filament cracking and de-forming
- It is 195mm in diameter. Hold easy 1 kg filament. Also (just) will fit most 3D printer beds.
- Filament lock holes for both start and end of filament.
- Large shaft center of 32mm fitting most 3d printer spool holders.
- No other parts needed, except 2x m4 screws.
- Little material as possible to speed up printing and reduce cost.

Lot of other spools need some tube as center. This spool does not need other parts, only 2x m4 screws to mount both parts of the spool together. I tried to remove as much material as possible to speed up printing, but still retain enough strength.
It has a large 100mm center, so 3 mm filament will not bent too much during winding. There are holes to hold filament when starting to wind. Also there are holes to hold the end of the filament after winding.

The spool is designed for a Lyman type of winder (