Anyone done this before? or know of a how to on going about this?
Also once I get these off I will replace them with high quality ones, guessing HIWIN per my search online.
I have a very strong feeling one of my bearing blocks is bad and has thrown my machine out of alignment. She is not squared.
A bit scared to do this but have to.
Thanks to all
Why do you think itās this and not some other alignment issue?
Iāve had mine down to remove the bearing, but didnāt replace the rail itself. My only worry is can you align it properly during replacementā¦ Like if they screw holes donāt line upā¦?
Unless the bearing blocks are loose meaning you can rock them in some direction, I doubt alignment issues would come from the actual slides. Also unless they are warped or bent. A laser doesnāt expose slides to high pressures or extreme speeds or high amounts of debris to cause any damage. I donāt believe that they need to be high quality. What makes you think the linear rails are causing alignment issues?
OK Sorry I have to say I miss lead with the topic/wording.
I think it is the bearing.
The reason I think it is this is because, I get the left rail and gantry squared and after a few uses it is unsquared by an 1/8th.
That doesnāt really sound like a bearing, unless itās worn.?
Do you have to āre-adjustā the same way?
Can you just replace the bearing?
That would be much more simple.
Well thatās what I would like to do is replace the bearing. But it is something I havenāt done before. My guess is I have to take the gantry off on that one side. Because it looks like the bearing block is connected to the gantry, then I can slide it out of the front end of the machine.
Unless you would happen to know a way for me to test this to make sure 100% that it is the bearing.
I opened up enough clearance on one end of the rail to remove the bearing, without taking off the rail.
Had the motor bracket off.
I will give this a shot.
I happen to have been changing out the motor mount for the Russ Sadler engineered āRack and Pinionā system. Check out the machine to see if it might be easier from the other end.
Watch out for ālittleā parts inside. Mine came off in one piece, no lose parts, but Iāve heard of some that had issues with some small parts inside.
If you think about what you are doing, I think youāll be fine. I doubt itās the bearing, but if you are convincedā¦
We are here if you have ideas youād like to bounce off usā¦ There is a vast knowledge base on this site and othersā¦
If I were you, Iād ask Russ Sadlerā¦ 
Take care, good luck
Sounds great. I will take some photos and share
Thanks again
āThe reason I think it is this is because, I get the left rail and gantry squared and after a few uses it is unsquared by an 1/8th.ā
To me this sounds like a belt or loose pulley issue. The gantry (X axis) is attached to the bearing block but those screws are not strong enough to rigidly maintain square. The timing belts on either side maintain square. I would perform the same checks after changing the bearing to prove the problem is resolved.
A lot of lasers are not truly square, I once paid Ā£28k for a 900x600 machine that could not cut true, when I stripped it doen the bearing rails were running off a few mm on both sides, there is wiggle room in the holes in the rails, I aligned mine starting with the left one, made sure it was 90 degrees to the shaft that controlled the y axis, then set the right rail so they were parallel, if i tried to cut a 600x600 square it would āleanā to the right nearly 10mm, once i reset the rails it was within less than 0.2mm, The biggest cause of failure of Recirculating ball bearings is using oil or wd40 to lubricate, these bearings need grease, any supplied from a decent supplier will have grease nipples fitted
These ālow costā machines rarely have zerk fitting on them.
When I looked at them on the market, the prices was at minimum 20% higher. Well worth itā¦
Of course if you do this with every part thatās āwell worth itā, it really adds up and isnāt the low cost hobby laser machine anymore.
The spouse refuses to tell me how much Iāve spent, above the cost of the machine. Claims she doesnāt want to diminish my enjoymentā¦
Was you 28k machine UK? For that kind of money Iād been on their backā¦
Here are a few photos of what I see when I place my square up from the left and right rails to the gantry .
The machine is 55x35 130w Does not cut 1x1 circles smooth at higher speed. But at very slow speeds it does. When I move the gantry by hand when it is off it is not very smooth or as smooth as I think it should be.
You bearing is on the top, mine is āfront facingā. Some claim itās a better design because of weight distributionā¦
I think you could put my whole machine in there
Thanks for the photosā¦
You can see how it is not squared from the images, shes a lot better from the right side, a lot off from left side.
I have used this machine for a lot of jobs shes been great but now I have to put a bit of TLC to her.
Gantry bearing is on top. Correct
Looking at your photoās Iād say your side rails arenāt parallel, the gantry will be swapping between sides trying to stay square to one side or the other and itāll be putting a lot of strain on the structure as it tries to accommodate the rails getting further apart.
Iād check which one was square to the gantry and loosen the other rail to see if there is enough movement to get it parallel to the first one, if not then you may have to file or re drill the holes to suit.
Also check the bearing blocks for slack on the rails.
Steve
Also just in case you donāt know, you can easily check how square the laser is cutting by marking a square box and then measuring diagonally corner to corner, and then the other set of corners should be the same measurement. It doesnāt actually have to be square, a rectangle will still work but a square is also handy for checking calibration so I do both at the same time.
Steve
Sorry for the late reply, Working all day.
But I sure will give this a try before taking her apart.
Thanks for the tips
