PitStop extruder 1.1 fits stock Prusa frames

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prairie_wren_1957 5 hours ago

Most extruder upgrades for Prusa printers seem to assume you will adapt the machine to the part. MihaiDesigns has gone the other way with PitStop version 1.1, folding support for the stock frame, the MK2.5S, the MMU2S and the Dragon hotend into one release. That breadth is unusual, and seeing the extruder assembled on an Original Prusa i3 makes the point better than any spec list could.

The hardware choices look sensible. Steel DIN 7 M6 cylindrical dowel pins and cylindrical neodymium magnets in 10 mm and 6 mm sizes do the joining. Builders in the United States can substitute 1/4 by 1/2 inch imperial magnets, with the printed sockets enlarged by a 1/4 inch drill bit without cracking the plastic. The main body goes together on a workbench before it slides onto the guide rods. Typical assembly takes four to five hours, with overall times between two and seven.

The details stand out. The MK2.5S carriage uses a socket head screw as an adjustable trigger for the homing switch, tuned with a hex tool. A revised blue filament sensor lever engages a microswitch for the MMU2S. The fan shroud matches the stock Prusa one but adds an angled blower fan mount, and washers under the shroud screws stop the cover rubbing the blades. The yellow parts wear pixelated lettering on the fan grill, and revised parts carry debossed v1.1 labels in nested folders per printer setup.

One thing is still open: a shroud redesign to improve cooling to the rear of printed parts is not ready yet. Meanwhile, take care with the PINDA holder, since overtightening its clamping screw risks fracture.

Project by MihaiDesigns. Watch it on their YouTube channel:

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PikeNomad64 4 hours ago

The adjustable socket head screw trigger for the MK2.5S homing switch strikes me as the cleverest part. Mechanical limit switches need a precise contact point, and threading in an ordinary screw means you can dial the trigger in with a hex tool instead of reprinting a whole carriage. That seems a smart way to absorb frame to frame variation.

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Pete_Plumb_1978 15 hours from now

How does the magnet fit work for people using imperial parts? The printed sockets are surely sized for the metric cylinders, so I am wondering whether the 1/4 by 1/2 inch magnets drop straight in or whether every socket needs reaming out on a stock build.

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HarvestBadger_1979 19 hours from now

The sockets are enlarged with a 1/4 inch drill bit, and the design gets the holes wide enough without cracking the plastic. The magnets themselves stack well, since the 10 mm and 6 mm cylinders are shown being handled and stacked, and either multiple shorter magnets or single 6 mm ones still give adequate holding force.

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dnolan82 1 day from now

If you print the shroud, use one of the heat-resistant materials the maker recommends, such as ASA, ABS or SLA resin, rather than hoping a less suitable plastic survives near the hot end. Also worth grabbing the magnets during a routine restock, because rapid purchasing pushed them out of stock and third-party listings came with higher costs or wrong dimensions.

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