Are Y-Axis and X-Axis perfect 90 Degrees?

I recently did the full maintenance on my OneFinity X-50 including cleaning the ball nuts on both of the Y-Axis rails. When I put them back together I ensured they were in the exact same place on their respective screws so that the X-Axis was a perfect 90 Degrees to the Y-axis.

What I notice is that when I home the Y axis, the distance to the silver guide is different on one side to the other by exactly 1/16. The gap is obviously different which is what made my pull out my caliper. I have tried to realign them again by loosening the X-Axis from the Y, manually turning the screw until they are perfectly lined up but when I hit home again, I am back off by the 1/16" of an inch. Should these two numbers in fact be exact? See the pictures below to further understand my question.

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I would measure to the block not the linear bearing, as the bearings may be inserted into blocks at varying distances.

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Same result, still shows a difference of 1/16" of an inch. I did run a quick G-code on the X-Axis and it does seem to be 90 degrees. I am just not sure why these two measurements would not be dead on.


When I took the (2) M5 screws off the tops of each Y block, I noticed that there was the potential for a bit of adjustment of how far apart the blocks could be. This would not be much, and I think that when they are assembled onto the tubes there is a recess inside that the tubes can be pushed against - I think this would make for repeatable assembly of the rails. I am curious, what measure do you get between the Y axis blocks, and is it the same on the left and right sides?

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I noticed that same thing when I was putting it back together after cleaning the ball screw that the X axis could slide slightly left to right and still have the bolts still catch so that the X block is not sitting perfectly flush on one of the Y axis blocks.

It looks like from the block on the bottom of the X Axis left to right is 37 3/4".

From the block on the Y axis it is 37 13/16.

My problem seems to be the distance of the Y blocks from the end on each side. I moved the gantry out further to make it a little better visual.

On the right side, I see, 5 1/32". One the left side, I see 5 3/32. See the pics below.

I did another test. I went into settings and set the zero-backoff on Motor 1 to 1/4. I saved the settings and homed the Y axis. Once it homed, I checked the measurement on the left rail, it was right on 1/4. On the right rail it was 3/16.

You guys ever figure this out? I see a nice new video on cleaning the ball nut on an X-50 but it shows the X Slider only. I see that instead of 4 countersunk bolts the Y Slider looks to have just two hex bolts that sit on top of the ball nut (and look more like the oil port). I figured it was just a matter of loosening these two bolt but then thought about this potential problem.

Any solution?

Hey Jim,

first, stall homing as used on the stock Onefinity Standard Series does not offer enough homing repeatability. However, the Onefinity allows retrofitting limit sensors which bring excellent homing repeatability.

There is a method to bring the Y axes back into sync.

First of course, the machine has to be checked fo rectangularity (that it is perfectly “squared”)

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Hey Jim,

Here are the two videos, first for ball screws on 35 mm rails and then for ball screws on 50 mm rails:

35 mm rail oil port:

50 mm rail oil port:

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Thanks, Aiph. (Big help, as always.)

My woodworker oil port on the Y rails look very similar to what’s above and that’s easy enough to put oil into. However, I’m assuming that I should occasionally take them out and clean them too. Your pic under the title “Inserting and extension to the OEM extensions cables” is also very close to what my X-50 Woodworker looks like for the Y rails. What I haven’t seen is a video (or instructions) that tell me how to take out that ball screw.

Beneath the oil port in that pic, you can see two hex bolts that are almost as big as the oil port bolt. (On the X axis example there are 4 smaller hex bolts.). So, I’m assuming those are simply the two bolts holding in the ball nut and I just take those two out and clean in the same way as the X axis video. And then, when I’m done, I use the “disconnect the two Y controller cables one at a time to home them separately until they are both against the ends” as per the other instructions and I’m good to go.

That sound right??

Regarding “Stall Homing”, after homing at startup I almost always Probe XYZ on the corner of two X/Y permanent fences on my wasteboard that I use to butt all my jigs (cut by the CNC) up against. Been working for me so far. So, although the stall homing isn’t perfect, is there something I’m missing by not having the upgraded sensors??

Thanks! (Here we go! I’m about to upgrade to v1.03 to finish my Spindle/VFD installation and very gun shy. Wish me luck…)

Hey Jim,

I already linked it above:

Exactly. Woodworker X-35 rails are in fact identical to the Y-35 rails on Journeyman (just as Journeyman X-50 rails are identical to Foreman Y-50 rails). This is the advantage of the modular system.

Here alle the Videos put together:

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Regarding “Stall Homing”, after homing at startup I almost always Probe XYZ on the corner of two X/Y permanent fences on my wasteboard that I use to butt all my jigs (cut by the CNC) up against. Been working for me so far. So, although the stall homing isn’t perfect, is there something I’m missing by not having the upgraded sensors??

With accurate homing sensors this step can be omited

Hey Pat, hey all,

You are totally right. By using the XYZ Touch probe, you bypass the stall homing inacuracy, as discussed e.g. in this thread the other day

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Hey Aiph!

Duh!!! I never watched the X-35 video because I don’t have an X-35 and there was the exact same video for the X-50; or so I thought. I see now that the X-35 video should have the title “Ball Nut Cleaning for X-35 & X-50 (Y Rails)” instead. And then title the other video should be “X-50 Ball Nut Cleaning for X Rail: Addendum.”

Either that or copy the Y Rail portion to the X-50 video. Giving them both the same exact title is misleading. Thanks for the help.

@OnefinityCNC Is it too late to change the titles??

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Hey Jim,

until now, Onefinity never called the Y axes “Y-35” or “Y-50”, but it’s me who does that because it is logical :slight_smile:

Model X axis Y axis
Machinist 16" X-35 × 16" Y-35
Woodworker 32" X-35 × 32" Y-35
Woodworker X-50 32" X-50 × 32" Y-35
Journeyman 48" X-50 × 32" Y-35
Foreman 48" X-50 × 48" Y-50

Left: Rail with 50 mm ø chrome-plated steel hollow shafts
Right: Rail with 35 mm ø chrome-plated steel hollow shafts

The photo was obviously made when there was a “Woodworker” and a “Woodworker X-50” version, but it shows the two sizes of Onefinity modular rails system.

See also


…" and Foreman Y rails" :slight_smile:

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Now the nomenclature starts to make a little sense! I never realized that I had X-35 rails (or, as you make it clearer “Y-35 Rails”). I saw X-50 and figured “That’s for me!”

So, what the two videos should be called are:

“Ball Nut Cleaning for X-35 Rails: Machinist, Woodworker & Woodworker X-50 (Y Rails) ”
“Ball Nut Cleaning for X-50 Rails: Woodworker X-50 (X Rail), Journeyman & Foreman"

@OnefinityCNC How about that???

No, correct would be:

“Ball Nut Cleaning for X-35 Rails: Machinist, Woodworker, Woodworker X-50 (Y Rails) and Journeyman (Y Rails)”
“Ball Nut Cleaning for X-50 Rails: Woodworker X-50 (X Rail), Journeyman (X Rail) & Foreman"

And I would switch to “Ball nut cleaning for 35 mm ø shaft rails” and “Ball nut cleaning for 50 mm ø shaft rails”

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Yep, you’re right. Simpler.

@OnefinityCNC Please take Aiph’s advice if possible. (Unless you think only X-50 owners are confused so it’s not worth it or that “just me” is confused! I realize it’s a strong possibility…)