Ender 3 S1 Y Axis Linear Shafts

Never worry about tinkering with wheels or bed wobble again! This is a replacement of the wheels on the Y axis carriage with linear shafts.

What you'll need:

2x 350 mm long 8 mm thick linear shafts. You can pick these up on amazon for around 10 bucks, or elsewhere for even cheaper.

4x LM8UU Linear Ball Bearings. This carriage is designed for them to be 24mm long.

8x M3 T-Nuts

8x M3 Washers

4x M4 Nuts

4x M4 Washers

4x M5 Washers

M3 machine screws for the brackets. I used the shortest ones I could get away with for each application.

M4 machine screws for the carriage. I used the shortest ones I could get away with for each application.

The whole thing can be built for less than 30 bucks depending on what you already have.

It is designed to be as unobtrusive as possible to install. You simply remove the print bed from the printer by unscrewing the leveling knobs, and removing the wheels and belt from the carriage to remove that as well. 

BRACKETS:

Install the brackets (back is assumed to be where the Y motor is, front is the belt tensioner) in the orientation listed in the part names by screwing them to the Y extrusion using the T nuts. If you're having trouble installing both T nuts on one bracket (it can be a pain), 1 will serve as long as it is rigidly secured. These use the M3 machine screws, M3 washers, and the T nuts.

CARRIAGE:

Screw the printed carriage to the bottom of the metal bed carriage that was removed from the printer. This is done with the M4 screws. The M4 washer goes between the screw and the bottom of the plastic carriage, then they are secured with the M5 washer and nut on top of the metal carriage (the larger washer is used to help bridge the gap of the larger holes). Finally, lubricate the bearings (I use a 5 buck spray can of white lithium grease from Harbor Freight), then push them into the 4 circular spaces on the carriage. They should fit relatively easily. Then secure them in place using 4x M4 screws, just screw them in until they stop advancing.

Finally, simply push the linear shaft through the front brackets, carriage bearings, and rear brackets, then depending on the fit (you may not have to do this if its tight), secure them with 4x M3 screws in a similar fashion you did the bearings. After this, simply add the belt back (make sure its tight!), then add the bed back on and relevel, and you're done! Depending on your installation you may have to reduce the range of the Y axis.

PRINT SETTINGS

Each part is designed to be able to be printed without supports, but depending on your printer you may want to use them with the front brackets anyway because the curve can be a bit tricky for it to pull off. Other than that, use .2 layer height, and use a heat resistant material for the carriage at least or else it warps and screws up your prints (I printed everything in PETG and haven't had an issue after a solid hundred hours of stress testing).

If you have any criticisms or have any ideas of what I should add, let me know in the comments, this is my first mod so I'm 100% open for feedback!