[WB-1]

Hi, how do you align x y z axis so that they are all perpendicular with each other???

Can someone provide a good link for this information.

I don't want a link to some fancy tool I need to do buy. I would have thought someone here must have found a way of doing it using basic tools and simple trigonometry.

Thanks.

[OCNC]

Make a g-code program that spot drills the four corners of a square on your machine bed (spoil board) and then measure the diagonals. Knowing the sides and the diagonals you should be able to calculate the correction you need to make in the Y relative to the X. Make an adjustment then repeat the procedure until you get the tolerance that you want. For setting the Z you need to follow a procedure know as 'tramming a mill'. I suggest googling that for the details and how you might apply it to your machine.

Chris

[PaulRowntree]

Chris has the best solution, as it makes the machine more and more accurate. Unfortunately, I was never able to get the last bit of 'skew' out of the gantry ... the X-Y angle was always ~0.12 degrees off perpendicular. So rather than kill myself and my machine, I wrote a couple of programs to do the fix in software. Ultimately, a CNC is a software-driven machine, so this is just add another link in the toolchain.

SkewCalculator does the math to measure the skew angle accurately, and then WarpDriver uses that information to skew the original g-code for your machine.

There is a 'manual' in the zip file. Just unzip it where you want to use it, there is no windoze registry or installation foolishness. Both SkewCalculator and WarpDriver can be downloaded for free from PaulRowntree.weebly.com
Cheers!
pr

[adprinter]

Are you referring to axis/software calibration, or physical calibration?
As for the physical, what I did, was to draw a right angle in CAD, and used an engraving bit to carve the two lines. Then simply checked with a machinist's square. Then made mechanical adjustments as needed, and repeated the test until I achieved a perfect 90 degree engraving.

For the Z, I drilled a 1/2" diameter hole into a piece of angle stock in the center of a length of 24" I then PRESSED a 1/2" diameter drill rod stock into the hole to assure a perpendicular fit. I then mounted two dial indicators (one on each end of the angle stock) by clamping them to the vertical plane of the angle stock. I placed the 1/2" drill rod into the chuck of my Router, Lowered the Z axis until I loaded the dial indicators to about 0.020" (and rezeroed each). I then rotated the Router spindle by hand, and observed the amount of adjustment needed by observing the dial indicators. (Leaning the gantry frame to or fro along the X axis, or adjusting the angle height of the cross bar of the Y axis) until I achieved about 0.0004" difference between the two dial indicators.

This is a VERY time-consuming process, but absolutely necessary to achieve any degree of acuracy in your build. You probably won't get it perfect, because it is after all a machine. And as parts begin to wear such as bearings, and drive screws, etc. You will find that further adjustments may be needed to compensate for wear.

The very first time you try to do an engraving of some small type faces (cut very shallow into the wood) will show your machine's lack of acuracy. (Assuming you have first used the machine to plane the surface flat!). This is when design of the machine, in terms of adjustability, comes into play. If it is a welded construction, your only option is to start cutting weld joints, and inserting shims, or applying elaborate clamps to try and force things into shape. And re-welding (and hoping that this action does not cause further warping, or twisting of your frame).

This is why I designed my machine as a bolt-together assembly. The addition of jack screws (while not absolutely necessary) are a convenient feature, when it comes to making this type of "fine-tune" adjustments. Although a light tap with a hammer can work, things still tend to shift slightly when bolts are once again locked back into place. The jack screws, or use of binders (depending on the part of the frame being adjusted), will allow you to "dial it in" by simply turning the jack screws or binders, with the lock bolts only slightly loosened. (Snug, but not locked). Hope this helps!

[Treischl]

Use the same technique a draftsman uses to check the squareness of a triangle.

First machine a straight edge parallel to the base axis of your machine.

Put a large piece of flat stock like 1/4 MDF against the machined straight edge.

Mill a slot perpendicular to the straight edge. Do NOT cut the sheet in half.

Flip the sheet over and use the same edge against the straight edge, mill a second slot close enough to the first so that you can measure it with a dial caliper or other accurate measuring tool.

Measure between the slots at both ends, the difference is exactly double the error. Adjust your machine, repeat the test until you are happy as a clam.

For spindle perpendicularity, take a 1/4 rod and make two 90 degree bends in it so it forms a double "L" shape. This does not have to be perfect.

Secure it in the spindle. Using feeler gages, rotate it around to see which sides are high or low. Simple as that.

[WB-1]

Hi thanks for the replies. I will post back once I'm finished.