Introduction: Roller Bearing to Linear Rails | Bed Leveling Issue | Kuongshun K10 3d Printer Y-axis Repair

So a couple of days ago I was printing a bigger object and I was so confused that my print bed was not leveled because I had just 3d printed something small and it turned out great. Whenever I leveled the bed it would be out of level from other portion. So I look around and found out that my bed was going up and down as I move it along the Y-axis and than I found out it was due to the roller bearings.

In this instructable I'm gonna show you how I changed the roller bearings to linear guides.
One thing I would like to clarify is that in Pakistan it is very difficult to import a 3d printer so I somehow managed to get this printer locally. I own a Kuongshun K10 3d Printer which is a Chinese 3d printer and it is a mixture of Geechtech A10 and Ender 3 but a little bit cheap. Anyone who owns Geechtech A10 or Ender 3 can also use the given files and modify them according to there requirement.


For this upgrade you need

1 M8x26mm Allen Screw and Nut
1 M6x26mm Allen Screw and Nut
4 M5x12mm Allen Screw and Nut
8 M3x5mm Allen Screw
16 M3x19mm Allen Screw
8 2020 t slot 3mm t slot nut
Linear Guides A4BI or A0J27 (Length 350mm, Width 9mm, Breadth 5mm)
608zz ball bearing
GT2 6mm Endless belt

The .stl files and obviously Kuongshun K10 3d Printer.

Step 1: Dismantling Y-axis

  • Take off the heat bed by unscrewing the bed leveling knobs.
  • Loosen the Belt tension mechanism and remove it.
  • Also remove the bed from the Aluminium extrusion.
  • Unscrew,remove and throw away those roller bearings into the sea :D.

Step 2: Mounting the Linear Guides

  • Prepare the linear guides by passing through a M3x5mm long Allen screw and loosely fasten it with a t nut. I have used 4 screw to fasten it on to the t slot.
  • Now here I mention that as we can notice a chamfer on the t slots and also there is a chamfer on the Linear guides, so I utilized that feature and fastened the linear guide. I didn't require any sort of calibration tool to fasten them.

Step 3: Print Settings

For Bed Mount and Spacer

Kuongshun K10

Resolution: 0.16

Infill: 80%

Filament_material: PLA

For Pulley mount, GT2 Inner and out sleeve and Nut Case :D

Kuongshun K10

Resolution: 0.16

Infill: 100%

Filament_material: PLA

Step 4: Preparing the Bed

  • Print the bed mount and spacer.
  • Mount the bed mount on the bed plate using 4 M5x12mm long Allen key nut and bolt.
  • Now align those spacers with the holes and stick 8 M3x19mm long screws on each side.
  • Place the bed on the Linear rails.
  • Align the holes and fasten them.
  • HERE I should mention that these M3 screws were actually 26mm long screws, I ground them to my size, so you guys might see a few of them with Washers. Due to the current situation of lock down I had to utilize whatever I had lying around.

Keep in mind that whenever you fasten the screws on a linear bearing(regardless of the fact that it is cylindrical or a block bearing) never tighten them to much, what happens is that when we tighten them too much they either pulley or push the bearing away from there corresponding side which result in a friction force that can be easily felt by pushing the linear actuator with hand.

Step 5: Installing Belt and Pulley Mechanism

  • I designed this mechanism 2 times. At first the design was not so bad but I miscalculated a few things. But it was good enough to print me another design. The problem was that I designed It around a GT2 12mm diameter idler pulley which was small because the bed acquired some elevation due to the newly designed parts. The idler pulley was small and the belt was fastened at a higher point due to which the belt was not in line with the pulley so the bed was not completely making its way towards the end, approximately 50mm of my bed area was unavailable due to this issue. So I redesigned this mechanism around 608zz ball bearing, I took kdmshark design for GT2 Idler pulley( and I modified my design accordingly.
  • I cut the belt according to the size by looping it around and keeping a little extra.
  • Pass the belt through the notch given in to the bed plate.
  • I used a paper clip to hold the two sides of the belt together and used a Zip tie to hold it in place, I used 2 zip ties to make sure it doesn't slip.
  • Now place the GT2 idler pulley around the belt.
  • Prepare the pulley mount by sliding an M6 26mm long Allen key screw.
  • Slide-in the Pulley mount and fastened it with an M8 26mm long Allen screw and nut.
  • Prepare the Belt fastener using a M6 nut and press it down into the cavity.

Step 6: Result

The linear guides works smoothly, the bed leveling issue is gone. They are better than the roller bearing, the belt tension mechanism also works great. A few prints I did after the upgrade. I would recommend everyone to replace those roller bearings to some other kind of linear actuator system because eventually they will fail. I hope this would have been a very helpful instructable.