Locking Spool Holder for the Prusa XL

When changing spools it is easy for the inside of the spool to accidentally touch the end of the telescoping spool holder and pull it out along with the spool. When there's not a lot of clearance along the side's of your XL, this can quickly become an annoyance.

This modification fixes this by introducing discreet slots inside the telescoping mechanism that one can rotate the outer sleeve into, locking it at that length. There are three such stops, fully in (for 1 Kg spools), fully out (for 2 Kg spools) and a slot between them both for good measure. You can still use any spool you would have used with the OEM version, but the lock is only available for these 3 positions.

There are two versions of the “slider”, one for the left side of the of the printer for tool-heads 1, 2, and 3. and the other is for the right side of the printer for tool-heads 4 and 5. The difference between them is simply that one is a reflection of the other. This means that as the printer pulls more filament from the spool, it doesn't “unlock” the telescoping mechanism. The “base” is the same for both.

The “base” is 3mm longer than the OEM version to allow for more tolerance into the connector. However, the end result is no taller than the original.

I printed mine in PETG at 0.25mm layer height. They are absolutely beautiful compared to the ones my printer came with (I think Prusa printed these parts as quickly as they could to meet consumer demand.) So, in addition to a functional improvement, I got an esthetic one too. =) In the provided photo, the spool holder on the left is this model, the one on the right is the OEM one that came with the printer. Black PETG is pretty hard to photograph, but the finish on the new one is so smooth, you can almost see one's own reflection.

The spool holder can be locked into any of 3 positions to reduce frustration when adding/removing spools.