Spool holder (modular)

This is a spool holder designed from scratch in OnShape

https://cad.onshape.com/documents/b18e4a474be7623d179a2956/w/786bb42a3f491a7321bdce8a/e/8b936b587468885eb7ab803d

See companion thing: https://www.thingiverse.com/thing:2543550

Inspired by: https://www.thingiverse.com/thing:914117

The holder is designed to hold 1kg spools with small (30mm) or large diameters, with a length of up to 100mm. Obviously it can be reconfigured via the OnShape link.

This is part of a design I've been working on, that allows easy printing of 3D spool holders and bases. These connect via a T-Slot and have a base that snaps to the printer and a holder.

**Features:**
- holds 1kg spools, thin or thick, might go up to 2kg (not thoroughly tested)
- "quick-change" spool design
- only the bare minimum material required, so it prints fast
- designed 'with-grain' instead of 'across-the-grain' so it reduces breakage
- no support or raft required
- plenty of clearance but has retainer washers b