Introduction

Trying to print on the entire bed of a 3D printer can be difficult at times. From my experience with a printer that didn’t have an auto bed level probe, there was only so much space I could print on and any adjustments I made would cause another part of the bed to just go out of whack. Once thing I appreciate about the MK3S is the PINDA probe, I honestly think it’s one of the best bed leveling systems I’ve ever used, it has it’s flaws but from working with other 3D printers this has been an amazing experience. After having the printer for some time, I started realizing that parts of the bed was uneven, so uneven that I might have perfect first layers in one area but layers that were too close in others. This wasn’t noticeable on small prints, but when I made a huge print that covered the entire bed, it was obvious that the bed wasn’t 100% flat. I did some research and stumbled on what was called the “nylock mod”, and my journey to a more leveled bed began.

The nylock mod is one of the most useful mods that you can do on your MK3/S. I feel like if you’re going to do any mod on your printer this is it. The beautiful thing about the MK3/S is that it is pretty smart when it comes to making sure the bed is leveled, but that only goes so far. Sometimes you get uneven spots that the mesh bed leveling just doesn’t always catch. This is where the nylock mod shines, the bed uses 9 screws; three towards the front, three in the middle, and three in the back. This setup effectively allows us to be able to make fine adjustments to various points on the bed, with some modifications of course. As always, I'm not responsible if you somehow ruin your bed, hurt yourself, and/or break anything on your printer, modifications should be done only if you're comfortable and know what you're doing.

One thing to note is that you need to have a Raspberry Pi running OctoPi. Please refer to my guide on how to get setup: OctoPi Setup Instructions. If you aren’t already using OctoPi with your MK3/S, you should even if you don’t want to do the nylock mod. OctoPi lets you do things like print wirelessly, monitor your printer via camera, start and cancel prints remotely, and so much more. There are tons of plugins out there that are super useful.

Tools and Material

A lot of these tools and supplies you may already have, but if not I’ve added affiliate links to what I have and what I bought when I did this mod:

Process

You’ll need to disassemble the bed in order to do this mod. Essentially, what you need to do is remove all the spacers except for the one in the middle of the bed. Once you remove all the spacers you add the nylon washers and the nyloc nuts in place of the spacers. I suggest placing the spacers in a baggy and storing them somewhere in case you ever want to switch back to stock. I’ve seen manufacturers say nylon washers will withstand up to 220C while I’ve heard stories of them melting at just above 90C, I’ve never had any issues with nylon washers since I usually heat my bed up around 65C-80C. You can leave out the washer if you plan on heating your bed beyond that or use something with higher heat resistance like PTFE washers to be safe.

To start, you want to unscrew the bed from the carriage and remove all the spacers, then you want to flip the bed on it’s back. One by one you want to insert the 3mm screw back into each of the holes on the bed, this time you will use the nylon washer and nylock in place of the spacer. The easiest way to do this is to hold the screw in place with the 2mm hex key while you tighten the nylock nut against the nylon washer, just tight enough that the nylock nut is flush against the washer but the screw still can be twist freely with the hex key but not too loose that they'll rattle, washers are used to keep the nut from scratching up the bed and helps to allow the screw to move freely. Do this for all the perimeter holes, exclude the hole in the middle of the bed, we will be using the spacer for that hole. Please note that you want the nylon side of the nut to be facing the outside. Refer to my picture if you don’t quite understand what I mean.