I made this so that I could better use plastic bushings on the bed of my Tronxy P802E instead of the noisy ball bearings. If plastic bushings are misaligned slightly they will bind and cause motor skips and getting them aligned can be very fussy business. These holders hold the bushing by single central cable tie which allows them to flex enough to avoid binding while holding them securely enough that there is no added wiggle to the bed. Made the switch to printed bushings much easier for me. What also made the transition to bushings work was my switch from the acrylic to an aluminum bed carriage. https://www.thingiverse.com/thing:2545713
My printers y stop switch touches off on the bearing block so that is why the one design has a wall on one end. That also gives them a more stable base for printing on end which gives a smoother saddle for the bushing.
I highly recommend ditching your noisy bearings for Igus or Igus style printed bearings. My prints are so smooth now! Even when my original bearings were in good shape it wasn't this nice.
I printed bearings from https://www.thingiverse.com/thing:1811769 as they have a nice selection of inner diameters so you can get that perfect fit. I am currently using PLA on my bed and nylon on my x carriage to see how they hold up.
Note: These bushings did require a bit more force to move than bearings even when well aligned, so I had to adjust my stepper up a bit to avoid skipped steps.
Do not lubricate with any oil or grease! I found that lubrication will increase static friction and increase skipping risk. It will make them slide easier once moving, but will be stickier when starting.
- UPDATE Jan 19 2018
I have tried a few different materials for printed bushings now for awhile and here are my thoughts
- NYLON (Taulmen Bridge) This has to much "stiction" (static friction). Slides smooth once moving, but is grippy when getting started. This is probably due to its rubbery nature. My motors could not provide enough torque to avoid skips.
- PLA This is the easiest gliding filament. Works really well. Only downside is that you do not want to run in a warm environment. I found that even 40C ambient can result in very slight deformations over time (especially if the bed is really hot). And this will eventually cause skips. 35C ambient seems to be very safe though.
- PETG Have been using for awhile on my x axis only and it works good so far. Doesn't slide quite as easily as PLA but not that much worse. No obvious stiction. My hope is that it will handle higher ambient temperatures better than PLA, but have not had it above 35C yet as I still have PLA on my bed bushings.
Again, I am not lubricating these bushings. All wet lubes dramatically increase stiction. I did try a dry Teflon spray and that did seem to help slightly, but the effect seemed very temporary and would require reapplication every handful of hours of printing.
UPDATE May 25 2018
See https://www.thingiverse.com/thing:2929741 for bushings specifically designed for this application.
Pla bushings were starting to bind slightly due to slowly deforming under the combination of a heated enclosure and a lot of 110c bed temperature time. So I replaced with petg bushings.
Print on end like they load in as for smoothest surface for bushing to set on. The flatter one should also print ok flipped down.