[slyvape]

Hello all
I found a sherline mill with an upgraded cnc kit at an estate sale and brought it home after a lot of playing around i was able to get it to at least function in using linuxcnc, however i cannot get accurate steps at all. if i use the predefined steps in linuxcnc i am off almost .01. the x and y lead screws have been updated to a2z 8tpi acme threads and the z axis is the 20tpi that is standard on the mill. i have messed around in the stepconfig application for days now and am no closer to accurate DRO to actual movement. below is my ini file. please any help would be greatly appreciated

# Generated by stepconf 1.1 at Wed Jul 27 19:50:57 2016
# If you make changes to this file, they will be
# overwritten when you run stepconf again

[EMC]
MACHINE = my-mill
DEBUG = 0

[DISPLAY]
DISPLAY = axis
EDITOR = gedit
POSITION_OFFSET = RELATIVE
POSITION_FEEDBACK = ACTUAL
ARCDIVISION = 64
GRIDS = 10mm 20mm 50mm 100mm 1in 2in 5in 10in
MAX_FEED_OVERRIDE = 1.2
MIN_SPINDLE_OVERRIDE = 0.5
MAX_SPINDLE_OVERRIDE = 1.2
DEFAULT_LINEAR_VELOCITY = 2.50
MIN_LINEAR_VELOCITY = 0
MAX_LINEAR_VELOCITY = 25.00
INTRO_GRAPHIC = linuxcnc.gif
INTRO_TIME = 5
PROGRAM_PREFIX = /home/john/linuxcnc/nc_files
INCREMENTS = .1in .05in .01in .005in .001in .0005in .0001in
PYVCP = custompanel.xml

[FILTER]
PROGRAM_EXTENSION = .png,.gif,.jpg Greyscale Depth Image
PROGRAM_EXTENSION = .py Python Script
png = image-to-gcode
gif = image-to-gcode
jpg = image-to-gcode
py = python

[TASK]
TASK = milltask
CYCLE_TIME = 0.010

[RS274NGC]
PARAMETER_FILE = linuxcnc.var

[EMCMOT]
EMCMOT = motmod
COMM_TIMEOUT = 1.0
COMM_WAIT = 0.010
BASE_PERIOD = 37000
SERVO_PERIOD = 1000000

[HAL]
HALUI = halui
HALFILE = my-mill.hal
HALFILE = custom.hal
POSTGUI_HALFILE = custom_postgui.hal

[HALUI]
# add halui MDI commands here (max 64)

[TRAJ]
AXES = 3
COORDINATES = X Y Z
LINEAR_UNITS = inch
ANGULAR_UNITS = degree
CYCLE_TIME = 0.010
DEFAULT_VELOCITY = 2.50
MAX_VELOCITY = 25.00

[EMCIO]
EMCIO = io
CYCLE_TIME = 0.100
TOOL_TABLE = tool.tbl

[AXIS_0]
TYPE = LINEAR
HOME = 0.0
MAX_VELOCITY = 2.0
MAX_ACCELERATION = 30.0
STEPGEN_MAXACCEL = 37.5
SCALE = 2880.0
FERROR = 0.05
MIN_FERROR = 0.01
MIN_LIMIT = -15.0
MAX_LIMIT = 15.0
HOME_OFFSET = 0.0

[AXIS_1]
TYPE = LINEAR
HOME = 0.0
MAX_VELOCITY = 2.0
MAX_ACCELERATION = 30.0
STEPGEN_MAXACCEL = 37.5
SCALE = 2880.0
FERROR = 0.05
MIN_FERROR = 0.01
MIN_LIMIT = -15.0
MAX_LIMIT = 15.0
HOME_OFFSET = 0.0

[AXIS_2]
TYPE = LINEAR
HOME = 0.0
MAX_VELOCITY = 1.78303303303
MAX_ACCELERATION = 30.0
STEPGEN_MAXACCEL = 37.5
SCALE = 7200.0
FERROR = 0.05
MIN_FERROR = 0.01
MIN_LIMIT = -10.0
MAX_LIMIT = 10.0
HOME_OFFSET = 0.0

[Fastest1]

Have you been to the linux site?LinuxCNC: Category Index

[Stan Stocker]

Greetings,
Your steps per inch looks hosed, you have 2880 and 7200 steps per inch it appears. Your 8 TPI ball screw steps should be 8 * (stepper steps per turn - usually 200) * integer value of micro-stepping.

If you are using a 200 steps per turn, 1/4 microstep (4) and 8 tpi your steps per inch will be 8 * 200 * 4 or 6400 steps per inch. As you have the original leadscrew for the Z axis, it's 20 * 4 * 200. This is based on the "inch" setting the the traj section of the ini file.

The following may help:
Basic Configuration

Good luck,
Stan