To save space, I created a new spool on top installation, with vertical axis.
This doesn’t work any better than the former Fisher spool on top, but is more compact and more elegant.
It does accept spool with 50mm + hole (with a ring) or 30mm + hole (without ring).
There is an untested spigot for spools with 19mm holes (say small Taulman spools).
While the support is only 130mm diameter, it is fairly stable with spool of 200mm diameter.
This replace the former spool on top support which was built with ball bearings.
As using bearings then adding a brake to improve unwinding was not really wise, I redesigned the system without ball bearings.
The braking depends of the spool weight, which is coherent with the fact that an empty spool do have a lower winding diameter, but for 0.5kg spool, the braking effect is fairly light. It is low but acceptable for a spool of 1kg, if printed in PETG. PLA may give a bit more braking effect (less slippery than PETG).
However, with usage, I found that vertical axis for spool tend to drive filament loops to fall down and cross, then make knots and stop prints.
So, except for constrained space (which was the case for me), I think basic spigot support shall be preferred (and is faster to print).
As spool holes are generally larger than 50mm, the spool is never perfectly centered, but this have no effect on the operation.
BOM list :
1 wood screw 4×25
Spool fixed foot
Spool rotating support
Ring for 50mm spool
Option: 19mm spigot
The spool axis position shall be adjusted depending your printer. You shall resist to the temptation to install it on center, which is generally far from being the best position for good filament path.
This is a relatively large part (diameter 130mm) to print on the Fisher Delta and I experienced skipping steps at first print. The plate with all printed parts uses 140mm diameter.
Top print it, you need :
A reasonably flat bed and properly calibrated machine
To reduce the travel speed (I used 180 mm/s) because you risk skipping steps at maximum diameter on some printers.
The last SD image of Fisher Delta have increased the travel speed from 200 mm/s to 250 mm/s. That may work for small parts, but with the geometry of the Fisher and its short arms, that is not ok for large parts. If still experiencing lost steps after reducing speed, you may reduce a bit the accelerations (G-Code M201)