This spool holder mounts on a NATO (STANAG) rail and utilizes 608 bearings. After printing another design from Thingiverse and noticing several areas I wanted to change, I decided to design my own from the ground up with AutoCAD and Fusion 360.
You’ll need to print –
1 x Locking Frame
1 x Floating Frame
2 x Keeper Plate
1 x NATO Rail
You’ll also need –
4 x 608 format bearings (I used these: https://www.amazon.com/gp/product/B01L7PIURQ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 )
4 x M5x18mm socket head cap screws
4 x M3x18mm socket head cap screws
1 x M3x50mm socket head cap screw
4 x M5 nuts
5 x M3 nuts
2 x #8 x ¾” flat head wood screw for rail mounting (hard to find metric here)
Notes:
The NATO rail was taken from actual design drawings so it is dimensionally correct. The NATO/STANAG/Picatinny rail is already a great design so I figured why reinvent the wheel! Although the rail is roughly 155 mm, it could easily be extended to allow for more than one holder etc. Let me know if this is preferred and I can update the design.
You could also use two locking frames, but one floating frame offers more flexibility in width.
I tried a number of grooved bearing cover designs for the rollers, but extensive drag testing showed that the bearing alone was best. As a side note, if you want really smooth bearings, remove the seals from the bearing, wash out the factory grease with IPA, and then put a tiny amount of thin oil (Remoil, etc) on the bearing before popping the seals back in.
The M3x50mm screw does a great job of locking the base into the rail groove and securing it, but don’t overtighten.
The bases may fit a bit tight on the rail initially – this is by design. Just run the base back and forth on the rail several times and it should be perfect!
Print with the screw head / nut holes facing down. There are supports already designed into the holes that will very easily pop out with a small screwdriver, etc.
The author hasn't provided the model origin yet.