Tweaking the code

These were the old GRBL config settings:


After some testing, I went with these settings:

However, after doing some test cutting, I found the actual measurements needed a bit of tweaking.

On a ideal 19" length, the laser cutter actually came out to 18 7/8".  

I found a multiplier by dividing the numbers, and applied that to the X and Y axis stepping number:

1.006622516556291 x 43.720 = 44.00953642384106

So for the new X and Y values, I used 44.010, which delivered spectaularly.

Additionally, I was confused about the feed rate of the machine.  I kept setting it lower, as It seemed like that was initially making it go faster.  However, after a bit of trial and error, I realized a higher feed and seek rate speed things up.  Generally the feed rate is controlled byt the CNC pattern file, or the sending program, so only the seek rate is important for the GRBL configs.

Speeding up the CNC made the cutting dot/lines much sharper.  The cutting line is now the approximate width of a line from a pen.


ordered some limit switches
flash newer GRBL hex
stop button

Download the latest Hex file of GRBL from here:

crafted brackets for limit switches


Setup limit switches
installed cable carrier


purchased an arduino protoshield to easily solder the leads for the limit switches, 12v rail, and all the pinouts
Rewired cables through cable carrier, and rerouted to arduino protoshield
used 12v plug to power arduino from the power supply

Configured Hard Limits in GRBL.
Not sure how to make automagic homing work yet.

Information on configuring the extend GRBL setup: