MGN12 Linear Rail Precision Motion Kit for Creality Ender 3

- Service is excellent.
- All CNC parts are good.
- Cheap chinese rails are SUBPAR. The ones I received are bent and have burrs left over. One of them can glide freely, but doesn't feel right some how, the bearings don't move uniformly. I have Hiwin rails and I can tell. I ordered another pair of other cheap chinese MGN12H rails by Twotrees. They are also wayyy better than the ones that come with the kit. They have no burr at all! I also replaced the stainless steel ball bearings with, chrome steel bearings, making them near Hiwin quality. ( 2 x Twotrees MGN12H + chrome bearings = $ ~40)

Also, don't just use 1 rail on the Ender 3 Pro. The bed mount would flex too much, create vibration and ringing/hosting. You need dual rail.

Purchased the kit for the Ender 3, wanted the 2 rail version but was not available for this printer. I decided to pay the extra money for the 3 point leveling kit as I had read good things about it. The order came in 2 parts, one from Amazon and the other from GulfCoast Robotics and they arrived on different days but I was ok with that. In the mean time I checked out the rail, It was binding and not a smooth movement as I was expecting, removing the glide??? noted a big gap between the steel balls, looked like it was missing 2 on each side. Cleaned the rail, re-lubricated and put back together and worked a bit better but was still binding in a particular spot even when cycling it back and forth for a few minutes and figured once the remainder of the kit arrived it might work better when installed or get smoother with use..
Installed the kit and totally disappointed.

The reason for getting this kit was because the original rubber wheels kept getting miss-adjusted and would develop a slack that would cause the bed to rock side to side and cause the prints to fail, my thinking was that using rails with their precision would eliminate that problem. The 3 point leveling system I was so exited to use, flopped on me as the rear right corner was way lower than the front and nothing I did could correct it. And yes, I researched this extensibly and this should not happen with this is system, and, my frame is squared. After running the printer since installation to see it the rail would even out is not happening as i got the components in mid September. I just eventually went back to 4 point and got a BL touch to help with the leveling which is not ideal but works.

Another problem that has cropped up is the belt tensioning system. The belt keep popping of the bed because it has a plastic clip holding it in place, and I keep having to take everything apart to re-attach. I tried holding it in place with tie wraps but just happened to me today again so I will have to find another system to hold them in place securely. The belt is wearing towards the front on the right side but am not sure if it's because I need to align something or because the front belt tensioning piece that was provided only attaches to the center beam on one side and its flexing so will need to check this further.

Looking back, I could have saved the money, gotten one of those cheap Chinese rails, print one of the kits available on the internet and probably gotten better results. As it stands, I it seems I received a cheap rail with the system that was defective from the get-go,

I really wanted this to to work because of the possibility of using the 3 point leveling and not having to deal with a wobbly bed would have been totally worth it it. They get 2 stars not 5 because even with the issues encountered they provide some nice quality parts, the aluminum plate for the bed is not warped, and it provided a slight weight reduction from the OEM part. Too bad the rail itself was crap.

Let me first state that the linear rail kit itself is superb, and works wonderfully on my old E3Pro. But, that's not why I'm here. Anyone can write a review of a product, but not many can write an honest review of the company behind it. This is that review.

I started by ordering the MGN12 kit a few weeks ago, as I had a worn spot on my Y-axis V extrusion and needed a more reliable solution. I'd heard and read great things about Gulf Coast Robotics online and from other makers, so I knew I wouldn't be disappointed. Alas, from the getgo there were a few hiccups, first with shipping, then with missing screws. Now before you assume this is a review lambasting the company, let me assure you it's not. Quite the opposite.

From the very outset, Brett at the crew at GCR have been exemplary in their customer service. First with the shipping issue, in which Brett generously refunded the shipping cost, and later with the missing screws. Each time I emailed him, I didn't have to wait days for some boilerplate, excuse-laden canned reply. No, Brett was first and foremost a complete gentleman who went out of his way to make things right. He didn't sugarcoat things. He didn't make excuses. And he didn't deflect when so many other companies might. I completely understood the issues and how the pandemic has affected so many industries, theirs included. Even when all I was seeking and expecting were the parts required, Brett one-upped that expectation and included a freebie that put a smile on my face. Needless to say, they have a very happy, future repeat customer. Not because of what they did, but because of who they are: A company who actually gives a s**t when so many others, quite frankly, don't.

It's easy to put words to page disparaging a company when things go wrong, but it's even easier to congratulate a company who actually cares about you as a customer, even with the occasional misstep. This isn't a review about a company. This is a review about the wonderful people at Gulf Coast Robotics who, even during the worst of times, put their hearts and souls into their products, their service and their company as a whole. Thank you Brett and the crew at GCR. You've made a customer for life, and a friend.

I added the dual rail complete kit to my Ender 3 Pro. Installation was straight forward and about 30 minutes. As it was the full kit I also upgraded my bed to 3 point leveling at the same time. Two small items to watch out for. The first time I tried homing the machine the Y axis did not hit the limit switch. I had to move the limit switch forward about 5 mm to get the extended portion of the slide to bed adapter to trip the limit switch. If I had know to watch for this I would have checked that the limit switch got tripped when the table was all the way to the rear of the machine before trying to home. The other item to watch for is on the 3 point bed mount. While it is obvious there is a right and a left, it is less obvious there is a front and a back. The front side has extra holed to allow mounting a handle or other accessories. This is not pointed out in the instructions and I initially installed it with the extra mount holes on the back side. It does function perfectly that way, but I wanted to add a handle and could not figure out how to mount it until I realized there was a front and a back and I needed to flip mine over.

The linear guides have made a big difference in the alignment of layers. They all come out nice and even instead of slight varying alignment I used to get. Run a finger across a wall and it is now super even.

The 3 point bed leveling is a great improvement. I use a BL touch but I still check the bed and level it to minimize the compensation needed. I would say the 3 point leveling is at least 50% faster than the original 4 point I have used for the past 18 months.

I upgraded as the complete kit. If I had to the linear guides or the 3 point bed leveling it would be a hard decision. Probably would do the linear guides as they made a noticeable improvement in the print. The 3 point bed level didn't affect the print, but sure is a convenient time saver.

This set is just like everything else I have gotten from Gulf Coast Robotics. Super high quality, amazing support, and very realistic prices.