LMU8 Y-Axis Brackets for Prusa i3 MK2/3 with Bear Full Upgrade

###Update 2019/01/09: I have unified all versions into one prefixing them with "AllMK". The bottom part fits also the old MK2.5 and MK3 specific versions. Furtermore, I added an A360 link to the source files - see further down in this section.###

I created bearing clips in the past for the Prusa i3 MK2 (which also fit the MK2.5 and MK3) to provide an alternative for the zip tie and the u-bolt mounting of the bearings underneath the heated bed carriage of the Y-axis.

However, because the original metal frame of the Prusa i3 series doesn't provide enough clearance to the linear motion system the clips had to be made minimal. This restriction made them less sturdy and lacking a cool feature I always wanted for the bearings, which is:

Replacing the bearings without having to disassemble the head bed from the carriage every single time!

After switching the printer's frame to the Full Bear Upgrade, there is now enough space under the Y-axis to make more elaborate brackets. And here they finally are!

The brackets consist of two parts. The upper (top) part remains attached to the carriage, guided into the correct orientation by using the carriage's notch and secured safely by two M3 screws. The screws are held in place by two nuts inside the bracket. There are versions for hex nuts and square nuts available.

The lower part (bottom) is then secured by four screws which attach to four nuts inside the upper part. Because of the design, the nuts will not fall out of the bracket at any time while the top mount is attached to the carriage, making the dis-/assembly easy.

Furthermore, the four screws distribute the clamping forces onto the bearing more evenly and reduce the stress on the bracket.

The brackets fit for all lmu8-alike bearings which have two notch-rings on the ends.

You will need six M3x18mm screws for this. Shorter screws may also work.

Do not use screws that are too long and which stick out of the top bracket because they will push against the carriage otherwise and cause problems.

Furthermore:

Due to the design of the brackets, the bed will be raised by about 3.3mm. If you haven't changed the Z-steps of the firmware settings, the Z calibration procedure should work without problems!

The source files for Fusion 360 and many other formats are available under:

https://a360.co/2Fk3R7w

Please read my print settings recommendations and the post-print section down below!

Your opinion on this design and suggestions to make it even better is appreciated

Please also take a look at my other designs, printer parts, and tools.

If you like to support me and my work, please consider following me on:

• Thingiverse
• MartinMajewski.net
• Twitter
• Instagram
• YouTube

Please also consider buying your next gear via one of the affiliate links provided next.

Products related to this project

• Ruthex/igus set of open and closed solid skew compensating bearings: Amazon.de Amazon.co.uk
• igus RJ4JP-01-08 drylin Bearings: Amazon.de Amazon.co.uk

Generic Affiliate Links

• Amazon.de
• Amazon.co.uk
• eBay Germany
• GearBest.com

Sending a tip over Thingiverse will buy me some coffee and a new spool of a filament to stay productive. :-)

Thank you very much.