Hi All, After months of debate, I finally picked a project and started building my first CNC machine. I selected the Root 2 CNC Root 2 CNC multitool router 3D printed parts by sailorpete The majority of folks that build this machine have been using Arduino Mega and RAMPS 1.4 for the "Brains" of the machine. Since I have built and modified 3D printers I know Marlin firmware. HOWEVER, I wanted to learn something new and decided to go the Arduino Uno and Prontoneer (spelling?) CNC GRBL Sheild for my machine. the Mechanics of the machine are fine, but I know absolutely nothing about setting up GRBL. I have read through the docs and I still have a couple of questions. Below is my current settings for GRBL $0=10 (step pulse, usec) $1=25 (step idle delay, msec) $2=0 (step port invert mask:00000000) $3=0 (dir port invert mask:00000000) $4=0 (step enable invert, bool) $5=0 (limit pins invert, bool) $6=0 (probe pin invert, bool) $10=3 (status report mask:00000011) $11=0.010 (junction deviation, mm) $12=0.002 (arc tolerance, mm) $13=0 (report inches, bool) $20=0 (soft limits, bool) $21=0 (hard limits, bool) $22=0 (homing cycle, bool) $23=0 (homing dir invert mask:00000000) $24=25.000 (homing feed, mm/min) $25=500.000 (homing seek, mm/min) $26=250 (homing debounce, msec) $27=1.000 (homing pull-off, mm) $100=200.000 (x, step/mm) $101=200.000 (y, step/mm) $102=200.000 (z, step/mm) $110=400.000 (x max rate, mm/min) $111=400.000 (y max rate, mm/min) $112=400.000 (z max rate, mm/min) $120=10.000 (x accel, mm/sec^2) $121=10.000 (y accel, mm/sec^2) $122=10.000 (z accel, mm/sec^2) $130=200.000 (x max travel, mm) $131=200.000 (y max travel, mm) $132=200.000 (z max travel, mm) Lines 100-102 and lines 110-112 I must be an idiot because I cannot figure out how to properly determine these settings. help? Also, I understand the latest version of GRBL supports spindle speed control. but i'm confused at how to go about implementing this? it talks about pin out, but my GRBL Shield doesn't appear to have a place for this? help? Thanks to any and all that can help me, I really appreciate it!