Aiph5u
(Aiph5u (not affiliated with Onefinity))
61
Hey Ziggy,
you understood well that you can do this with the geometrical method that I mentioned in a posting above, but unlike I suggested here earlier (with the little raspis), later I came to the conclusion not to use the base of the Onefinity’s feet as measuring points to measure the diagonals but rather the points where the rails go into the Y anodized aluminium blocks. The rails are adjustable within their pockets in the aluminum blocks in order to adjust the tilt between upper and lower rail, and therefore they are not always in a predetermined position relative to the corners of the feet. And it’s the rails where the gantries run, not the feet – so better measure on the rails.
Using Starrett things is always a joy, but you can also use the simpler Bar Gauge Heads that I recommend with wooden sticks with sharpened edge, like in the images shown in this item description at Lee Valley website:
Also as Tom mentioned here, the distance between the two blocks on one side can be different on left and right side. And the equal-diagonals method only works in a rectangle, not in a trapezoid, so first measurement should be whether y=y’! The good thing is, this can also be done with the same Bar Gauge method!
One thing to be aware of if your Y rails are different length, and you’re measuring/setting squareness from corner to corner. If done perfectly, you may have the condition shown (exaggerated) below. When you home your machine, it will be off 1/2 of the difference between the actual Y axis lengths. @Ziggy, your .007" would be inconsequential for the most part, this is just theory to keep in mind.
Can anyone comment on this issue when using the QCW frames? Hoping I nipped it in the bud by purchasing one … still waiting on my machine so no hardware to play with yet.
Agreed, stack-ups can be different between the two Y rails. Referencing only one would be advantageous to preventing trapezoid in addition to the parallelism issue.
Would you think it wise to first make sure the X rail does not have ‘twist’ too as it could exacerbate the situation as well?
Yes, absolutely. Very good point Phil. Otherwise, you couldn’t be sure if your indicator was reacting to a twist in the X axis or an out-of-square condition.
I used my L.H. Y rail as the primary fixed reference, then set the R.H. rail afterwards.
i did inside corner to inside corner. had my GF hold the tape on the 10 inch mark on the inside and we corner squared. i was out 1/8 of an inch on initial setup.
I’ve been squaring my Woodworker for a few hours now. I also started with a parallelogram. It wasn’t easy to fix it. I would like to give you my feedback and I hope it helps.
Firstly I tried to align my Y rails to achieve a perfect square. I wasn’t able to have equal diagonals after many adjustments. So here are a few things to take into consideration.
I based my measurements on the distances between the axes’ feets. So was my mistake… I took my caliper and the feets seem to have a slightly different size (~0.5-1mm)…
I also measured the length of both Y axis tubes and they are also slightly different. My left Y rail s
was a tiny bit longer (also around 0.5 to 1mm max) than the other. I don’t know if it moved during transport but I didn’t try to correct it because I don’t have a flat granite table. But it’s a parameter to also take into consideration.
After taking all these parameters into account I managed to have a perfect square with equal diagonals. When I put the X axis on top of my Y, I can feel my finger that the aluminum blocks (left side only) are not perfectly flush, there is a tiny step like the X axis is slightly rotated. But it’s not, it’s perfectly square to the Y rails. Do you guys also have to slightly misalign the X axis?
I then put two screws and let the machine finish the squaring process (like mention in the manual)
Then I put a pin in my router and I pointed squares on my wasteboard (600x800, 800x800) and the diagonals are good! Finally.
I wasted a lot of time basing my measurements on the rails’ feet. Be careful!
5 Likes
Aiph5u
(Aiph5u (not affiliated with Onefinity))
69
Hey Inoc,
thank you for your valuable experience and advice!
I feel a little responsible for anybody measuring at the feet since it was me who suggested this at an earlier stage of enlightenment (see many postings earlier), when I did not have my machine yet. Later I corrected this:
@makerjace
This is complicated a little bit when you have a QCW because everything screws down into place. My X50 was also a parallelogram (for geometry nerds it was actually a rhombus given that it has four equal sides) and 1F support was telling me that all I had to do was do a 90 degree cut with the rails to set my fence/jig. However, it was a little off because the QCW tolerances couldn’t make it exact right out of the box. It was close but not true.
So, I loosened several of the QCW bolts and kept clamping/bumping until the X fence and Y fence were actually square by using a big metal square as a guide. Once I got it there I screwed it back down and it was square.
Thank you for your answer. No worries. At first, it was obvious to measure the distance between the feets to calculate the square. I should have read this thread more carefully :D.
I went a bit crazy because the measurements between both feets (y and y’) were the same (+ / -)… But on y, the feets were a bit shorter and the tubes a little bit longer than y’…
Here’s another idea to check square. Have the machine cut the largest 3-4-5 triangle possible for your machine. A journeyman should be able to cut a 27x36x45 triangle. A woodworker can do a 24x32x40 (i just scaled up the triangle by a factor of 8 for the woodworker and 9 for the journeyman.). The longest side will be the diagonal. This will give you some nice even numbers to measure. You can ‘cut’ the triangle any way you want. You can use a narrow taper bit and barely cut into your spoilboard or use a regular bit and cut around it. Or even use the taper bit to just mark the three corners. The two legs of the right triangle should be exactly the length of the two shortest sides of the triangle. If everything is square then the diagonal will measure exactly the longest dimension. If the number is larger than it should be then the “square” angle is a little over 90 degrees. If it’s less then it’s a bit under. Now the accuracy of this will come down to how accurately you can measure the diagonal. The advantage of this is that you are measuring the actual path the machine follows and it will be independent of the actual length of the x or y rails.
4 Likes
Aiph5u
(Aiph5u (not affiliated with Onefinity))
73
Hey Woody,
thanks for your contribution. This is a variation of the possibilities to check for rectangularity after adjustment by letting the machine mill something, but can also be part of a method of adjustment itself. It should be clear that in the end the relevant thing is always what the machine mills, thank you for pointing that out here, in the end you’ll have to mill points that you can check for rectangularity. This has been covered here on a few occasions, but it’s a bit scattered around the forum, e.g. here, here and here, or here Tom @TMToronto used a needle as a test tip in a self-made CNC pen holder and stitched into cardboard on the wasteboard in order to be able to check rectangularity.
The problem with this topic is the same as with many other topics, you need to read a while to collect all the information to finally be able to judge on what is the best practicable solution.
Today, I would suggest: Create a rectangle as large as the workarea as g-code and run it on the machine using a v-bit (with minimal cutting depth), and then use a bar gauge to check whether or not the diagonals are equal.
Yep. That is what I described doing on my March 28th post. The diagonals gets you in the ballpark but then to correct for any differences in length you need to check and see how it cuts and then adjust accordingly based on that.
1 Like
Aiph5u
(Aiph5u (not affiliated with Onefinity))
75
I made a final check with a V bit to confirm the alignment of the machine. Unfortunately, I still have an issue…
I graved 4 points with my V Bit:
A: 0;0
B: 0:800
C: 800:800
D: 800: 0
I measured the first diagonal (AC) and it was a little bit over 113.1mm. This is perfect according to the maths : sqrt(80^2+80^2) = 113.14cm
But for the second diagonal (BD), I measure over 113.2cm.
How can it be possible? As far as I can measure, everything seems to be square and if my frame was a parallelogram, I wouldn’t have 113.13mm for one diagonal.
I tried to home hundreds of times and also reboot the controller (it homes like a charm btw, the distances with the aluminum blocks are equals).
Do you think I have an issue with one Y rail? Or a motor maybe?
Haha so so true, I think I also need to read it periodically. For the Woodworker, as I’m new with CNCs, I don’t know if 1mm would be critical…
Yes but if I set Y:800, the longer rail should have less space before the aluminum block than the other. Which is my case. I aligned the twos rails based on their first block.
For standalone pieces (3d carves or text engraving and the like) I doubt you’d ever notice. If you are building assemblies where fitment is important, might still not matter, it depends on your allowable tolerances.
1 Like
Aiph5u
(Aiph5u (not affiliated with Onefinity))
81
Hey Inoc,
to move the machine to the four points, did you use G1 commands entered into command entry field of the MDI tab?
Have you measured your four A̅B̅, B̅C̅, C̅D̅, and D̅A̅ to be exactly 800 mm? Especially to check if A̅B̅=C̅D̅ and B̅C̅=D̅A̅? Otherwise you would not have a rectangle (or a square in this case with Woodworker)
Did you check your machine for coplanarity? If your front left corner is 1 mm higher than the right rear corner, this would lead to the diagonal to be .07 mm longer – the distance you mention (113.2-113.13)
