Locking screw master spool for refills

Hi, I've seen a lot of burst refill spools recently. I wanted to avoid this with my first refill and modified a multi-spool by inserting 3 holes for locking screws. (I usually only use one screw though)

As with most other solutions, the spool is closed in on itself, the screws then only serve as a safety device in case the printing part should give up.

In the meantime I have made 2 versions: one with heated inserts and one where the nuts are printed directly into the spool.

To screw them together you need at least one countersunk screw M4x60 and 3x M4 nuts or 3x inserts.
One spool is using around 125g of filament

Any questions or requests? please just ask!

Got support, poop and failed prints? Recycle it!

added secure screws, changed design