M30x1.5 spool holder

The main screw body prints parallel to the build plate for strength.

• The diameter of the screw is 30mm (M30x1.5).
• The round tube to cover the screw has outer diameter 32.4mm.
• The hex nut has outer diameter approximately 52.5mm.
• The “tight-spool” nut has maximum outer diameter 37mm, asymmetrically to one side.
• The shorter tube is 75mm.
• The longer tube is 90mm.
• The screws are long enough to engage 15mm with the holder arm and have 5mm beyond the tube for a nut.

Be aware that the flat screws are prone to cross-threading; take extra care to screw them into the arm straight and screw on the nuts straight.

Background

When using the excellent Spool Saver to print from a broken cardboard spool, I found that it didn't fit over the flanged end of the stock spool holder.  The Spool Saver's inner diameter is about 39mm, while the stock spool holder flange is around 45mm.  I could unscrew the stock one and screw it back in through the Spool Saver, and that worked, but it was a lot of hassle.

Looking at other spool holder models, many of them printed perpendicular to the bed, which seemed like it might be prone to breaking in or near the threads, so I wanted to design one where at least the threaded part to attach to the holder arm printed parallel to the bed. I made the whole core that screw, made a tube to cover it so that the spool rests on something smooth (maybe not necessary), and made two options to keep the spool on the holder: a bigger nut that's sturdy, easy to use, and fits through most of my spools; and a “tight-spool” nut that's just small enough to fit through the Spool Saver and just big enough to keep the spool on the holder.