How to calibrate printer.

I was trying to follow this guide on calibrating my printer but I cannot figure out how to set the steps per mm. The piece I print is egg shaped. Where do I change the steps per mm for the axis’s?

You would have to change them in the firmware itself. It’s basically the same process as flashing the firmware on the printer.

Parts printing out of round is usually an indicator of a loose belt or a motor pulley that has a loose setscrew. It would be unusual in the extreme for the axis calibration to be off if you are using the correct factory firmware. The Extruder calibration "e steps is another issue, as that can vary with the hobbed bolt slightly. If your parts are off, and the belts are plenty tight you may want to reflash the factory firmware (after editing in the esteps value you recieved with your printer). Here are the guides and instructions for that process:

That has little do do with what I am talking about though. For one that link has nothing to do with the mini. The only link on the site that i have found that has the mini firmware is

And how does that help with egg shaped parts anyway? Would not the extruder be the same on x and y? I am about 7 thousands out of round at the moment. ( y=1.4955",x=1.5025" ).

If needed I can go get a proper indicator and check the axis’s that way rather than trying to measure a print.

It has everything to do with what you asked about. If you want to adjust the Y axis steps in firmware, you have to modify and flash the firmware. Mini or TAZ, the process is the same and thats how you do that. The step value is in configuration.h. To set or change the “Steps per MM” you change the firmware value.

If your printer is off in the Y axis direction though, it’s probably due to a loose belt. The steps value for X and Y are the same on the stock printer. They use the same belts, they use the same NEMA 17 moitors, the same pulleys and the same idler bearings. If your prints are off on one axis, that means the belt is loose enough that it is allowing the print head to travel beyond the point where the printer thinks it was supposed to stop. Think of it this way. If you tied a rope to each of your arms and handed one end to a person standing on either side of you, then told them to tighten up the rope until your arms were straight out, you wouldn’t be able to move closer to either person without ripping one of your arms out of the socket. If you told each person to take a step closer towards you, you would then be able to travel 2 steps closer to either person without ripping your arms off, because of the slack in the rope.

Whichever Axis is larger than the other one is probably the one with the Loose belt. Potentially your Xa axis if the numbers below are correct. Centripetal force makes the print head go to the furthest extents it can travel at the top or bottom of the arc. If the belt is too lose, it will travel that much further at every point along that arc of travel on a parabolic trajectory. A loose motor pulley can also cause this effect. The slipping of the pulley on the shaft in both directions also causes an offset in both directions of Axis travel.

What you describe there is backlash. And backlash compensation is axis specific. (Assuming these printers do backlash although I don’t see why you would leave out such a thing.)

When talking about a belt driven system, backlash is the amount of elastic error in the GT2 Timing belt. In this instance where you have a hardware issue with your printer in that the belt is incorrectly tightened, or the pulley set screws are loose in one direction, its kind of not so much. If you are certain your belts are both at the correct tension and all the pulleys are down and locked, and the firmware values are all correct, then you have some other weird sort of issue going on. It could be the model you are printing is out of round as well. Or not flat on the bottom so it is printing at an angle.