2-Pack CR10 Z axis T8 Anti Backlash Spring Loaded Nut Elimination Gap Brass Nuts for Upgrade Ender 3 Ender 3s Ender 3 Pro V2 CR-10 Tornado 3D Printer 8mm Acme Threaded Rod (Nuts)

These backlash couplers do what I want them to do on my CR-10S and thats to keep the z axis from moving when I power down the machine. Before I installed these I used this machine for 3 years and frustratingly had to level my bed almost every time I used the machine! I could literally see the jackscrews move when I powered down thereby destroying my bed levelling. These backlash couplers put enough drag on the z axis screws to prevent them from moving (usually downward) when turning off the machine. My bed stays at the proper level the next time I use it, which is the way it should be! I put backlash in quotes because this device is not really doing anything in regards to backlash and thats not its primary purpose. Its purpose is to prevent movement of the jackscrews when you power down so as to preserve your bed level adjustment.

Fits the stock z-axis bracket fine, but had a slight fitment issue with my second z-axis bracket. Filed the holes a bit bigger on the second bracket and it fit fine. Nuts might seem like they dont fit the lead screws at first. May take some persuasion to get them to seat into the threads on the lead screws.

like other reviews... the mount holes do NOT fit an Ender 3v2 or clone thereof... at least not without modification, i also had to take the Z rod and screw it on from the bottom side because it wouldnt start the threads from the bottom of the nut initially.... and finally... like other reviews, there is a grinding/binding noise at lower points (bed operating height) of the Z shaft. again, this is rectifiable... (read c.mercers review fixed my problem) with modifications... SO, even though this IS a cheap solution, and IS useable if youre capable... based on solely the quality of manufacture of this product... though its not a direct fit, plug and play part for the described machine its sold as... which equals 1 star, and not reccommended if youre looking for the quick fix this is supposed to be.

So, I can’t say for sure that these things are working. But, they are tight and so are my lead screws so I think they are. They are probably one of those things that you don’t see working but know they are. Would buy again.

Bolts dont line up on Ender 3 Pro. Essentially useless for my dual z set up. May try and swap for a new set, maybe it was a one off, otherwise the one star sticks for bad QA. Side note, on a test fit on the guide screw, it seems like this would lead to binding. Seems like the threads are off ever so slightly after a few twists you feels a good amount of resistance, then it lets off, then tight, then loose, etc etc. Again... could just be bad QA.

I was concerned by other reviews that said that these didnt fit correctly. They must have fixed the issue because they bolted right on to my Ender 3 Pro, and also fit my dual Z kit from TH3D. They took care of my inconsistent Z layers... Ill be recommending these to others as something cheap to upgrade right away.

Attempted to use these with some Oldham couplings on my Ender 3 Pro but had to use the original factory z screw nuts instead since the bolt hole pattern was too wide on these. Unfortunately cant return now as past the date. 1 star as description states it works with Ender 3 Pro.

Definitely grips on to the lead screw, use 2 on an ender 3 v2 with dual z-axis. Not sure if it does much but I would say it definitely does hold the lead screw better.

Recommend to help solve backlash issues on your 3D printer

One of the couplers was burred and too tight. No free movement at all. The holes on the coupler do not line up with the holes on the backlash not. Cant be used together at all.