Tag: Sherline

Sherline CNC mill

Vacuum Tube LEDs: 21HB5A on a Guilloche Platter

With the Joggy Thing running in LinuxCNC 2.7, touching XY off on the fixture was trivially easy:

LinuxCNC – Sherline Mill – Logitech Gamepad

The pips are 100 mm apart at (-50,-50) and (+50,50). Astonishingly, the laser aligner batteries are in fine shape.

I should have protected the platter before drilling all those holes:

Guilloche platter – drilling

All’s well that ends well:

21HB5A – Guilloche platter

It looks even better in the dark, although you’d never know it from this picture:

21HB5A – Guilloche platter – dark

I wish I could engrave those patterns on already-drilled platters, but dragging a diamond point into a hole can’t possibly end well. I could deploy the Tiny Sandblaster with a vinyl mask, if I had enough artistic eptitude to lay out a good-looking mask.

2018-11-23

LinuxCNC 2.7 vs. Logitech Joggy Thing

The old Atom running LinuxCNC for the Sherline finally stopped booting, so I popped the Optiplex 760 off the stack and did a live-USB trial run. The latency / jitter worked out around 25 µs, slightly worse than before, but still Good Enough, and the StepConf utility coerced the motors into working OK.

What didn’t work was the old Eagle-to-HAL code defining the Logitch Gamepad as a Joggy Thing to allow smooth joystick jog control. Well, stuff changes over the course of eight years, but, in this case, the fix turned out to be a one-liner: the probe_parport module isn’t needed nowadays.

With that out of the way, it runs fine:

LinuxCNC - Sherline Mill - Logitech Gamepad — LinuxCNC – Sherline Mill – Logitech Gamepad

The INI and HAL files defining the Sherline configuration as a GitHub Gist:

	# HAL config file automatically generated by Eagle-CAD ULP:
	# [/mnt/bulkdata/Project Files/eagle/ulp/hal-write-2.5.ulp]
	# (C) Martin Schoeneck.de 2008
	# Charalampos Alexopoulos 2011
	# Mods Ed Nisley KE4ZNU 2010 2013
	# Path [/mnt/bulkdata/Project Files/eagle/projects/LinuxCNC for M2/]
	# ProjectName [LinuxCNC Sherline Configuration]
	# File name [/mnt/bulkdata/Project Files/eagle/projects/LinuxCNC for M2/LinuxCNC Sherline Configuration.hal]
	# Created [11:17:21 17-Feb-2013]



	####################################################
	# Load realtime and userspace modules
	loadrt trivkins
	loadrt [EMCMOT]EMCMOT key=[EMCMOT]SHMEM_KEY num_joints=[TRAJ]AXES base_period_nsec=[EMCMOT]BASE_PERIOD servo_period_nsec=[EMCMOT]SERVO_PERIOD traj_period_nsec=[EMCMOT]SERVO_PERIOD
	# not needed in 2.7
	# loadrt probe_parport
	loadrt hal_parport cfg="[PARPORT]ADDRESS out"
	loadrt stepgen step_type=0,0,0,0
	loadrt pwmgen output_type=0
	loadusr -W hal_manualtoolchange
	loadusr -W hal_input -KA Dual
	loadrt logic count=1 personality=0x104
	loadrt constant count=13
	loadrt and2 count=17
	loadrt conv_float_s32 count=1
	loadrt flipflop count=4
	loadrt mux2 count=5
	loadrt mux4 count=1
	loadrt not count=8
	loadrt or2 count=14
	loadrt scale count=7
	loadrt timedelay count=1
	loadrt toggle count=1


	####################################################
	# Hook functions into threads
	addf stepgen.make-pulses base-thread
	addf pwmgen.make-pulses base-thread
	addf parport.0.read base-thread
	addf parport.0.write base-thread
	addf parport.0.reset base-thread
	addf logic.0 base-thread
	addf motion-command-handler servo-thread
	addf motion-controller servo-thread
	addf stepgen.update-freq servo-thread
	addf stepgen.capture-position servo-thread
	addf pwmgen.update servo-thread
	addf constant.0 servo-thread
	addf constant.1 servo-thread
	addf constant.2 servo-thread
	addf constant.3 servo-thread
	addf constant.4 servo-thread
	addf constant.5 servo-thread
	addf constant.6 servo-thread
	addf constant.7 servo-thread
	addf constant.8 servo-thread
	addf constant.9 servo-thread
	addf constant.10 servo-thread
	addf constant.11 servo-thread
	addf constant.12 servo-thread
	addf and2.0 servo-thread
	addf and2.1 servo-thread
	addf and2.2 servo-thread
	addf and2.3 servo-thread
	addf and2.4 servo-thread
	addf and2.5 servo-thread
	addf and2.6 servo-thread
	addf and2.7 servo-thread
	addf and2.8 servo-thread
	addf and2.9 servo-thread
	addf and2.10 servo-thread
	addf and2.11 servo-thread
	addf and2.12 servo-thread
	addf and2.13 servo-thread
	addf and2.14 servo-thread
	addf and2.15 servo-thread
	addf and2.16 servo-thread
	addf conv-float-s32.0 servo-thread
	addf toggle.0 servo-thread
	addf flipflop.0 servo-thread
	addf flipflop.1 servo-thread
	addf flipflop.2 servo-thread
	addf flipflop.3 servo-thread
	addf timedelay.0 servo-thread
	addf or2.0 servo-thread
	addf or2.1 servo-thread
	addf or2.2 servo-thread
	addf or2.3 servo-thread
	addf or2.4 servo-thread
	addf or2.5 servo-thread
	addf or2.6 servo-thread
	addf or2.7 servo-thread
	addf or2.8 servo-thread
	addf or2.9 servo-thread
	addf or2.10 servo-thread
	addf or2.11 servo-thread
	addf or2.12 servo-thread
	addf or2.13 servo-thread
	addf not.0 servo-thread
	addf not.1 servo-thread
	addf not.2 servo-thread
	addf not.3 servo-thread
	addf not.4 servo-thread
	addf not.5 servo-thread
	addf not.6 servo-thread
	addf not.7 servo-thread
	addf scale.0 servo-thread
	addf scale.1 servo-thread
	addf scale.2 servo-thread
	addf scale.3 servo-thread
	addf scale.4 servo-thread
	addf scale.5 servo-thread
	addf scale.6 servo-thread
	addf mux2.0 servo-thread
	addf mux4.0 servo-thread
	addf mux2.1 servo-thread
	addf mux2.2 servo-thread
	addf mux2.3 servo-thread
	addf mux2.4 servo-thread


	####################################################
	# Set parameters
	setp parport.0.reset-time [PARPORT]RESET_TIME
	setp stepgen.0.maxaccel [AXIS_0]STEPGEN_MAXACCEL
	setp stepgen.0.maxvel [AXIS_0]MAX_VELOCITY
	setp stepgen.0.dirhold [PARPORT]DIRHOLD
	setp stepgen.0.dirsetup [PARPORT]DIRSETUP
	setp stepgen.0.steplen [PARPORT]STEPLEN
	setp stepgen.0.stepspace [PARPORT]STEPSPACE
	setp stepgen.0.position-scale [AXIS_0]SCALE
	setp parport.0.pin-03-out-reset FALSE
	setp parport.0.pin-05-out-reset FALSE
	setp parport.0.pin-07-out-reset FALSE
	setp parport.0.pin-09-out-reset FALSE
	setp parport.0.pin-17-out-reset FALSE
	setp stepgen.1.maxaccel [AXIS_1]STEPGEN_MAXACCEL
	setp stepgen.1.maxvel [AXIS_1]MAX_VELOCITY
	setp stepgen.1.dirhold [PARPORT]DIRHOLD
	setp stepgen.1.dirsetup [PARPORT]DIRSETUP
	setp stepgen.1.steplen [PARPORT]STEPLEN
	setp stepgen.1.stepspace [PARPORT]STEPSPACE
	setp stepgen.1.position-scale [AXIS_1]SCALE
	setp stepgen.2.maxaccel [AXIS_2]STEPGEN_MAXACCEL
	setp stepgen.2.maxvel [AXIS_2]MAX_VELOCITY
	setp stepgen.2.dirhold [PARPORT]DIRHOLD
	setp stepgen.2.dirsetup [PARPORT]DIRSETUP
	setp stepgen.2.steplen [PARPORT]STEPLEN
	setp stepgen.2.stepspace [PARPORT]STEPSPACE
	setp stepgen.2.position-scale [AXIS_2]SCALE
	setp stepgen.3.maxaccel [AXIS_3]STEPGEN_MAXACCEL
	setp stepgen.3.maxvel [AXIS_3]MAX_VELOCITY
	setp stepgen.3.dirhold [PARPORT]DIRHOLD
	setp stepgen.3.dirsetup [PARPORT]DIRSETUP
	setp stepgen.3.steplen [PARPORT]STEPLEN
	setp stepgen.3.stepspace [PARPORT]STEPSPACE
	setp stepgen.3.position-scale [AXIS_3]SCALE
	setp parport.0.pin-04-out-invert TRUE
	setp parport.0.pin-06-out-invert TRUE


	####################################################
	# Set constants
	setp constant.0.value 0.1
	setp constant.1.value 20
	setp constant.2.value [TRAJ]MAX_LINEAR_VELOCITY
	setp constant.3.value [TRAJ]MAX_ANGULAR_VELOCITY
	setp constant.4.value 60
	setp constant.5.value 0.50
	setp constant.6.value 1.00
	setp constant.7.value 0.10
	setp constant.8.value 0.10
	setp constant.9.value 0.0
	setp constant.10.value -1.0
	setp constant.11.value 0.020
	setp constant.12.value 0.000


	####################################################
	# Connect Modules with nets
	net a-amp-enable logic.0.in-03 axis.3.amp-enable-out stepgen.3.enable
	net a-analog halui.jog.3.analog mux2.4.out
	net a-button-minus or2.0.in0 input.0.btn-joystick and2.7.in0
	net a-button-plus or2.0.in1 input.0.btn-thumb2 and2.8.in0
	net a-buttons-active or2.0.out or2.1.in0 or2.11.in1
	net a-direction parport.0.pin-08-out stepgen.3.dir
	net a-disable not.7.out and2.13.in1
	net a-enable or2.11.in0 flipflop.3.out not.7.in mux2.4.sel
	net a-jog input.0.abs-z-position mux2.4.in1
	net a-knob-active or2.9.out not.2.in and2.15.in1
	net a-knob-inactive not.2.out and2.14.in1
	net a-select and2.16.in0 and2.15.out
	net a-set flipflop.3.set and2.16.out
	net a-step parport.0.pin-09-out stepgen.3.step
	net all-amps-enabled logic.0.and parport.0.pin-17-out
	net angular_motion or2.11.out mux2.0.sel
	net any-buttons-active mux4.0.sel0 or2.12.out
	net axis-disabled-value constant.9.out mux2.1.in0 mux2.2.in0 mux2.3.in0 mux2.4.in0
	net az-buttons-active or2.1.out or2.12.in1 or2.13.in0
	net az-reset flipflop.2.reset and2.14.out flipflop.3.reset
	net button-crawl scale.4.out mux4.0.in3
	net button-fast scale.2.out mux4.0.in1 scale.4.in
	net estop-a and2.0.in0 input.0.btn-top2
	net estop-b and2.0.in1 input.0.btn-base
	net estop-out parport.0.pin-01-out iocontrol.0.emc-enable-in iocontrol.0.user-enable-out
	net homeswitches parport.0.pin-10-in-not axis.0.home-sw-in axis.1.home-sw-in axis.2.home-sw-in axis.3.home-sw-in
	net jog-crawl toggle.0.out mux4.0.sel1
	net jog-speed halui.jog-speed mux4.0.out
	net knob-crawl mux4.0.in2 scale.3.out
	net knob-fast mux4.0.in0 scale.1.out scale.3.in
	net manual-mode halui.mode.manual input.0.btn-base3
	net n_9 axis.0.motor-pos-cmd stepgen.0.position-cmd
	net n_11 axis.0.motor-pos-fb stepgen.0.position-fb
	net n_13 and2.0.out halui.estop.activate
	net n_14 or2.3.in0 input.0.btn-base5
	net n_15 or2.3.in1 input.0.btn-base6
	net n_16 toggle.0.in or2.3.out
	net n_17 conv-float-s32.0.out input.0.abs-x-flat input.0.abs-y-flat input.0.abs-z-flat input.0.abs-rz-flat
	net n_18 constant.1.out conv-float-s32.0.in
	net n_19 constant.4.out scale.0.gain
	net n_20 constant.5.out scale.1.gain
	net n_21 constant.6.out scale.2.gain
	net n_22 constant.7.out scale.3.gain
	net n_23 scale.4.gain constant.8.out
	net n_24 constant.0.out halui.jog-deadband
	net n_25 constant.2.out mux2.0.in0
	net n_26 mux2.0.in1 constant.3.out
	net n_34 axis.1.motor-pos-cmd stepgen.1.position-cmd
	net n_36 axis.1.motor-pos-fb stepgen.1.position-fb
	net n_42 or2.7.in0 input.0.abs-x-is-pos
	net n_43 or2.7.in1 input.0.abs-x-is-neg
	net n_44 or2.8.in0 input.0.abs-y-is-pos
	net n_45 or2.8.in1 input.0.abs-y-is-neg
	net n_46 or2.9.in0 input.0.abs-z-is-pos
	net n_47 or2.9.in1 input.0.abs-z-is-neg
	net n_48 or2.10.in0 input.0.abs-rz-is-pos
	net n_49 or2.10.in1 input.0.abs-rz-is-neg
	net n_51 constant.10.out scale.5.gain scale.6.gain
	net n_54 constant.11.out timedelay.0.on-delay
	net n_55 constant.12.out timedelay.0.off-delay
	net n_56 timedelay.0.out and2.1.in1 and2.2.in1 and2.4.in1 and2.3.in1 and2.5.in1 and2.6.in1 and2.8.in1 and2.7.in1
	net n_57 and2.1.out halui.jog.0.minus
	net n_58 and2.2.out halui.jog.0.plus
	net n_59 and2.3.out halui.jog.1.minus
	net n_60 halui.jog.1.plus and2.4.out
	net n_61 and2.5.out halui.jog.2.minus
	net n_62 and2.6.out halui.jog.2.plus
	net n_63 and2.7.out halui.jog.3.minus
	net n_64 and2.8.out halui.jog.3.plus
	net n_67 axis.2.motor-pos-cmd stepgen.2.position-cmd
	net n_69 axis.2.motor-pos-fb stepgen.2.position-fb
	net n_77 axis.3.motor-pos-cmd stepgen.3.position-cmd
	net n_79 axis.3.motor-pos-fb stepgen.3.position-fb
	net probe-in parport.0.pin-15-in-not motion.probe-input
	net program-resume halui.program.resume input.0.btn-base4
	net reset-estop input.0.btn-base2 halui.estop.reset
	net tool-change iocontrol.0.tool-change hal_manualtoolchange.change
	net tool-changed hal_manualtoolchange.changed iocontrol.0.tool-changed
	net tool-number iocontrol.0.tool-prep-number hal_manualtoolchange.number
	net tool-prepare-loopback iocontrol.0.tool-prepare iocontrol.0.tool-prepared
	net vel-per-minute scale.0.out scale.1.in scale.2.in
	net vel-per-second mux2.0.out scale.0.in
	net x-amp-enable logic.0.in-00 axis.0.amp-enable-out stepgen.0.enable
	net x-analog mux2.1.out halui.jog.0.analog
	net x-buttons-active or2.5.in0 or2.4.out
	net x-direction parport.0.pin-02-out stepgen.0.dir
	net x-disable not.4.out and2.12.in1
	net x-enable not.4.in flipflop.0.out mux2.1.sel
	net x-hat-minus or2.4.in1 input.0.abs-hat0x-is-neg and2.1.in0
	net x-hat-plus or2.4.in0 input.0.abs-hat0x-is-pos and2.2.in0
	net x-jog input.0.abs-x-position mux2.1.in1
	net x-knob-active or2.7.out not.0.in and2.9.in0
	net x-knob-inactive not.0.out and2.10.in0 and2.11.in0
	net x-set and2.9.out flipflop.0.set
	net x-step parport.0.pin-03-out stepgen.0.step
	net xy-buttons-active or2.5.out or2.12.in0 or2.13.in1
	net xy-reset flipflop.0.reset and2.10.out flipflop.1.reset
	net xyza-buttons-active or2.13.out timedelay.0.in
	net y-amp-enable logic.0.in-01 axis.1.amp-enable-out stepgen.1.enable
	net y-analog halui.jog.1.analog mux2.2.out
	net y-buttons-active or2.6.out or2.5.in1
	net y-direction parport.0.pin-04-out stepgen.1.dir
	net y-disable not.5.out and2.9.in1
	net y-enable flipflop.1.out not.5.in mux2.2.sel
	net y-hat-minus or2.6.in1 input.0.abs-hat0y-is-neg and2.4.in0
	net y-hat-plus or2.6.in0 input.0.abs-hat0y-is-pos and2.3.in0
	net y-jog input.0.abs-y-position scale.5.in
	net y-jog-reversed mux2.2.in1 scale.5.out
	net y-knob-active not.1.in or2.8.out and2.11.in1
	net y-knob-inactive not.1.out and2.10.in1
	net y-select and2.12.in0 and2.11.out
	net y-set flipflop.1.set and2.12.out
	net y-step parport.0.pin-05-out stepgen.1.step
	net z-amp-enable logic.0.in-02 axis.2.amp-enable-out stepgen.2.enable
	net z-analog mux2.3.out halui.jog.2.analog
	net z-button-minus or2.2.in0 input.0.btn-thumb and2.5.in0
	net z-button-plus or2.2.in1 input.0.btn-top and2.6.in0
	net z-buttons-active or2.2.out or2.1.in1
	net z-direction parport.0.pin-06-out stepgen.2.dir
	net z-disable not.6.out and2.16.in1
	net z-enable not.6.in flipflop.2.out mux2.3.sel
	net z-jog input.0.abs-rz-position scale.6.in
	net z-jog-reversed scale.6.out mux2.3.in1
	net z-knob-active not.3.in or2.10.out and2.13.in0
	net z-knob-inactive not.3.out and2.15.in0 and2.14.in0
	net z-set and2.13.out flipflop.2.set
	net z-step parport.0.pin-07-out stepgen.2.step

view raw Sherline.hal hosted with ❤ by GitHub

	# Ed Nisley – KE4ZNU
	# Just do not run stepconf ever again…

	[EMC]
	MACHINE = Sherline-XYZA
	DEBUG = 0
	RS274NGC_STARTUP_CODE = G21 G40 G49 G54 G80 G90 G92.1 G94 G97 G98

	[DISPLAY]
	DISPLAY = axis
	EDITOR = gedit
	GEOMETRY = AXYZ
	POSITION_OFFSET = RELATIVE
	POSITION_FEEDBACK = ACTUAL
	MAX_FEED_OVERRIDE = 3.0
	INTRO_GRAPHIC = /home/ed/linuxcnc/configs/Sherline-XYZA/Sherline.gif
	INTRO_TIME = 3
	PROGRAM_PREFIX = /mnt/bulkdata/
	#PROGRAM_PREFIX = /home/ed/linuxcnc/nc_files/
	#INCREMENTS = .1in .05in .01in .005in .001in .0005in .0001in
	INCREMENTS = 10 mm, 1 mm, 0.1 mm, 90 deg, 45 deg, 10 deg

	[FILTER]
	PROGRAM_EXTENSION = .py Python Script
	py = python

	[TASK]
	TASK = milltask
	CYCLE_TIME = 0.010

	[RS274NGC]
	PARAMETER_FILE = emc.var

	[EMCMOT]
	EMCMOT = motmod
	SHMEM_KEY = 111
	COMM_TIMEOUT = 1.0
	COMM_WAIT = 0.010
	BASE_PERIOD = 50000
	SERVO_PERIOD = 1000000

	[PARPORT]
	ADDRESS = 0x378
	RESET_TIME = 10000
	STEPLEN = 25000
	STEPSPACE = 25000
	DIRSETUP = 50000
	DIRHOLD = 50000

	[HAL]
	HALUI = halui
	HALFILE = Sherline.hal
	HALFILE = custom.hal
	POSTGUI_HALFILE = custom_postgui.hal

	[TRAJ]
	AXES = 4
	COORDINATES = X Y Z A
	MAX_ANGULAR_VELOCITY = 45.00
	DEFAULT_ANGULAR_VELOCITY = 36.0
	LINEAR_UNITS = inch
	ANGULAR_UNITS = degree
	CYCLE_TIME = 0.010
	DEFAULT_VELOCITY = 0.400
	MAX_LINEAR_VELOCITY = 0.400
	POSITION_FILE = lastposition.txt
	NO_FORCE_HOMING = 1

	[EMCIO]
	EMCIO = io
	CYCLE_TIME = 0.100
	TOOL_TABLE = Sherline.tbl
	TOOL_CHANGE_AT_G30 = 1

	[AXIS_0]
	TYPE = LINEAR
	MAX_VELOCITY = 0.400
	MAX_ACCELERATION = 5.0
	STEPGEN_MAXACCEL = 10.0
	SCALE = 16000.0
	FERROR = 0.05
	MIN_FERROR = 0.01
	MIN_LIMIT = -1.0
	MAX_LIMIT = 9.5
	BACKLASH = 0.003
	HOME_IS_SHARED = 1
	HOME_SEQUENCE = 1
	HOME_SEARCH_VEL = 0.3
	HOME_LATCH_VEL = 0.03
	HOME_FINAL_VEL = 0.4
	HOME_OFFSET = 9.1
	HOME = 5.25

	[AXIS_1]
	TYPE = LINEAR
	MAX_VELOCITY = 0.400
	MAX_ACCELERATION = 5.0
	STEPGEN_MAXACCEL = 10.0
	SCALE = 16000.0
	FERROR = 0.05
	MIN_FERROR = 0.01
	MIN_LIMIT = 0.00
	MAX_LIMIT = 5.10
	BACKLASH = 0.003
	HOME_IS_SHARED = 1
	HOME_SEQUENCE = 2
	HOME_SEARCH_VEL = 0.3
	HOME_LATCH_VEL = 0.03
	HOME_FINAL_VEL = 0.4
	HOME_OFFSET = 5.1
	HOME = 4.5

	[AXIS_2]
	TYPE = LINEAR
	MAX_VELOCITY = 0.333
	MAX_ACCELERATION = 3.0
	STEPGEN_MAXACCEL = 6.0
	SCALE = 16000.0
	FERROR = 0.05
	MIN_FERROR = 0.01
	MIN_LIMIT = 0.0
	MAX_LIMIT = 6.680
	BACKLASH = 0.005
	HOME_IS_SHARED = 1
	HOME_SEQUENCE = 0
	HOME_SEARCH_VEL = 0.150
	HOME_LATCH_VEL = 0.015
	HOME_FINAL_VEL = 0.33
	HOME_OFFSET = 6.680
	HOME = 6.500

	[AXIS_3]
	TYPE = ANGULAR
	###WRAPPED_ROTARY = 1
	MAX_VELOCITY = 40.0
	MAX_ACCELERATION = 250.0
	STEPGEN_MAXACCEL = 275.0
	SCALE = 160.0
	FERROR = 1
	MIN_FERROR = .25
	MIN_LIMIT = -999999999.9
	MAX_LIMIT = 999999999.9
	HOME_SEARCH_VEL = 0
	HOME_LATCH_VEL = 0
	HOME = 0.0

view raw Sherline.ini hosted with ❤ by GitHub

2018-11-22

T-shirt Shop Rags

Small wipes made from worn-out cotton t-shirts absorb most shop liquids, don’t overstay their welcome after short projects, and prevent the deep emotional attachment leaving swarf in the clothes washer. Scissors cutting gets tedious, so mooch a rotary cutter and slash away:

T-shirt shop rags

Synthetic fabrics don’t work nearly as well as cotton, so pay attention to the labels.

2017-10-28
Plotter Grit Wheel Bushings

As part of recommissioning the lathe tailstock, I made some bushings to adapt Dremel sanding ~~drums~~ bands to an 8 mm shaft (in imitation of the grit drive wheels on the HP plotter):

Plotter Y bushing – samples

They’re not all the same because the lad who’s building the plotter got to turn out his own bushings. We think the knurled version, with a setscrew to lock it on the shaft, will work better than adhesive-bonding the drum to the bushing.

The overall process starts with a rough 1/2 inch aluminum rod. Skim-cut to get a concentric surface and face the end smooth:

Plotter Y bushing – facing

Then knurl it:

Plotter Y bushing – knurling

The skim cut makes the aluminum rod a loose fit inside the sanding band, but the knurling enlarges the diameter enough to make it a firm press fit and I think it’ll have enough traction to stay in place.

FWIW, the wheels in the LittleMachineShop knurling tool seem pretty bad: the central holes aren’t quite concentric with the cutting edge, the bores are a loose fit on the mounting screws, the wheels are much narrower than the slots they ride in, so they wobble uncontrollably. It’s not a fatal flaw, but they definitely produce a sub-par knurl.

Face off the front, cut the knurling down at each end, then part it off:

Plotter Y bushing – cutoff

Clamp it in the Sherline mill, laser-spot the edges, set the origin in the middle, and center drill:

Plotter Y bushing – center drill

Drill and tap for a teeny M3 setscrew:

Plotter Y bushing – tapping

Clean out the chips, debur the hole, install the setscrew, and you’re half-done: do it again to get the second drive roller!

2017-10-19

NEMA17 Motor and Bearing Mounts

As part of coaching a student (and his father!) on their incredibly ambitious build-a-plotter-from-scratch project, I suggested ~~stealing~~ using HP’s grit-wheel paper drive, rather than fiddling with guide rods to move either the pen carrier or the entire paper platform. Dremel sanding drums seem about the right size and they had an 8 mm shaft harvested from a defunct printer, so a pair of mounts moves the project along:

NEMA17 and Bearing Mounts - Slic3r preview — NEMA17 and Bearing Mounts – Slic3r preview

The motor mount code is a hack job from my old NEMA17 mount and the code has a lot not to like. The bearing mount puts the bearing on the proper centerline using brute force copypasta and depends on friction to hold it in place. The two models should be integrated into the same file, the shaft centerline shouldn’t involve the printed thread width, and blah blah blah:

I had him turn the shaft adapter from an aluminum rod in the mini-lathe: he’s hooked.

The OpenSCAD source code as a GitHub Gist:

	// Ball bearing mount
	// Ed Nisley KE4ZNU 2017-10-09

	//– Extrusion parameters

	ThreadThick = 0.20;
	ThreadWidth = 0.40;

	HoleWindage = 0.2; // enlarge hole dia by this amount

	function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);

	Protrusion = 0.1; // make holes look good and joints intersect properly

	//– Useful sizes

	inch = 25.4;

	Tap10_32 = 0.159 * inch;
	Clear10_32 = 0.190 * inch;
	Head10_32 = 0.373 * inch;
	Head10_32Thick = 0.110 * inch;
	Nut10_32Dia = 0.433 * inch;
	Nut10_32Thick = 0.130 * inch;

	// Bearing sizes

	ID = 0;
	OD = 1;
	LENGTH = 2;

	Bearing = [8.0,22.0,7.0];

	ShaftHeight = IntegerMultiple(25.2,ThreadWidth); // arbitrary or copied from motor mount

	WallThick = 3.0;

	//– Mount Sizes

	MountSize = Bearing[OD] + 2*WallThick;

	BaseThick = max(WallThick,ShaftHeight – MountSize/2); // baseplate

	StandBoltHead = IntegerMultiple(Head10_32,2); // bolt head rounded up
	StandBoltClear = 1.25 * StandBoltHead;

	StandBoltOC = IntegerMultiple(MountSize + StandBoltClear,2);

	StandLength = StandBoltOC + StandBoltClear;
	StandThick = StandBoltClear + WallThick;
	StandHeight = MountSize + BaseThick;

	Cutout = (StandLength – MountSize)/2;

	echo(str("Stand Base: ",StandLength," x ",StandThick," x ",BaseThick));
	echo(str("Stand Bolt OC: ",StandBoltOC));
	echo(str("Shaft Height:",ShaftHeight));

	//———————-
	// Useful routines

	module PolyCyl(Dia,Height,ForceSides=0) { // based on nophead's polyholes

	Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2);

	FixDia = Dia / cos(180/Sides);

	cylinder(r=(FixDia + HoleWindage)/2,
	h=Height,
	$fn=Sides);
	}

	//———————-
	// Put it together

	module BearingMount() {

	difference() {
	translate([BaseThick/2,0,StandThick/2])
	cube([StandHeight,StandLength,StandThick],center=true);
	translate([0,0,-Protrusion])
	PolyCyl(Bearing[OD],(StandThick + 2*Protrusion));
	for (j=[-1,1]) // cutouts over bolts
	translate([-(StandHeight/2 – ShaftHeight + WallThick),
	j*(StandLength/2 – Cutout/2 + Protrusion/2),
	(WallThick + StandThick/2)])
	cube([StandHeight,
	Cutout + Protrusion,
	StandThick],center=true);
	for (j=[-1,1]) // stand bolt holes – base
	translate([(MountSize/2 – Protrusion),
	j*StandBoltOC/2,
	WallThick + StandBoltClear/2])
	rotate([0,90,0])
	rotate(180/6)
	PolyCyl(Clear10_32,BaseThick + 2*Protrusion,6);
	for (j=[-1,1]) // stand bolt holes – back
	translate([0,j*StandBoltOC/2,-Protrusion])
	rotate(180/6)
	PolyCyl(Clear10_32,StandThick + 2*Protrusion,6);
	translate([0,-(MountSize/2 – ThreadWidth/2),(StandThick – WallThick)/2 + WallThick])
	rotate([90,180,0])
	linear_extrude(ThreadWidth,convexity=10)
	text(text=str(ShaftHeight),size=6,spacing=1.20,font="Arial",halign="center",valign="center");

	}

	}

	//———————-
	// Build it

	BearingMount();

view raw Bearing Mount.scad hosted with ❤ by GitHub

	// NEMA 17 stepper mount
	// Ed Nisley KE4ZNU August 2011
	// Tweaked & thinned 2017-10-09

	//– Extrusion parameters

	ThreadThick = 0.25;
	ThreadWidth = 0.4;

	HoleWindage = 0.3; // enlarge hole dia by this amount

	function IntegerMultiple(Size,Unit) = Unit * ceil(Size / Unit);

	Protrusion = 0.1; // make holes look good and joints intersect properly

	//– Useful sizes

	inch = 25.4;

	Tap10_32 = 0.159 * inch;
	Clear10_32 = 0.190 * inch;
	Head10_32 = 0.373 * inch;
	Head10_32Thick = 0.110 * inch;
	Nut10_32Dia = 0.433 * inch;
	Nut10_32Thick = 0.130 * inch;



	NEMA17_ShaftDia = 5.0;
	NEMA17_ShaftLength = 24.0;
	NEMA17_PilotDia = 0.866 * inch;
	NEMA17_PilotLength = 0.080 * inch;
	NEMA17_BCD = 1.725 * inch;
	NEMA17_BoltDia = 3.5;
	NEMA17_BoltOC = 1.220 * inch;

	//– Mount Sizes

	MountWidth = IntegerMultiple(NEMA17_BCD,ThreadWidth); // use BCD for motor clearance
	MountThick = IntegerMultiple(4.0,ThreadThick); // for stiffness

	MountBoltDia = 3.0;

	StandThick = 3.0; // baseplate

	StrutThick = IntegerMultiple(3.0,ThreadWidth); // sides holding motor mount

	UprightLength = MountWidth + 2*StrutThick;

	StandBoltHead = IntegerMultiple(Head10_32,5); // bolt head rounded up
	StandBoltOC = IntegerMultiple(UprightLength + 2*StandBoltHead,5);

	StandLength = StandBoltOC + 2*StandBoltHead;
	StandWidth = 2*StandBoltHead;

	StandBoltClear = (StandLength – UprightLength)/2; // flat around bolt head

	MotorRecess = StandWidth – MountThick;

	ShaftHeight = IntegerMultiple(StandThick + MountWidth/2,ThreadWidth);

	echo(str("Stand Base: ",StandLength," x ",StandWidth," x ",StandThick));
	echo(str("Stand Bolt OC: ",StandBoltOC));
	echo(str("Shaft Height:",ShaftHeight));
	echo(str("Strut Thick: ",StrutThick));

	//———————-
	// Useful routines

	module PolyCyl(Dia,Height,ForceSides=0) { // based on nophead's polyholes

	Sides = (ForceSides != 0) ? ForceSides : (ceil(Dia) + 2);

	FixDia = Dia / cos(180/Sides);

	cylinder(r=(FixDia + HoleWindage)/2,
	h=Height,
	$fn=Sides);
	}

	//———————-
	// Model

	module MotorMount() {

	difference() {
	translate([StandThick/2,0,StandWidth/2])
	cube([(MountWidth + StandThick),StandLength,StandWidth],center=true);
	translate([-Protrusion/2,0,StandWidth – (MotorRecess – Protrusion)/2])
	cube([(MountWidth + Protrusion),MountWidth,(MotorRecess + Protrusion)],center=true);
	translate([0,0,-Protrusion]) // pilot hole
	PolyCyl(NEMA17_PilotDia,(MountThick + 2*Protrusion));
	for (i=[-1,1]) // motor bolt holes
	for (j=[-1,1])
	translate([iNEMA17_BoltOC/2,jNEMA17_BoltOC/2,-Protrusion])
	PolyCyl(MountBoltDia,(MountThick + 2*Protrusion),6);
	for (j=[-1,1]) // cutouts over bolts
	translate([-Protrusion/2,
	j*((StandLength – StandBoltClear)/2 + Protrusion/2),
	StandWidth/2])
	cube([(MountWidth + Protrusion),
	(StandBoltClear + Protrusion),
	(StandWidth + 2*Protrusion)],center=true);
	for (j=[-1,1]) // stand bolt holes
	translate([(MountWidth/2 – Protrusion),j*StandBoltOC/2,StandWidth/2])
	rotate([0,90,0])
	rotate(180/6)
	PolyCyl(Clear10_32,StandThick + 2*Protrusion,6);

	translate([0,-(UprightLength/2 – ThreadWidth/2),StandWidth/2])
	rotate([90,180,0])
	linear_extrude(ThreadWidth,convexity=10)
	text(text=str(ShaftHeight),size=6,spacing=1.20,font="Arial",halign="center",valign="center");

	}

	}

	//———————-
	// Build it

	MotorMount();

view raw NEMA17 Mount.scad hosted with ❤ by GitHub

2017-10-18

More Tommy Bar Handles

Having used a nail for far too long, this is a definite step up for my machinist vises:

Tommy Bar – machinist vise

The vise knob has a hole just barely passing a length of 3.4 mm = 9/64 inch mild steel rod from the Small Box o’ Cutoffs.

While I was at it, I made a handle for the parallel jaw clamps:

Tommy Bar – parallel jaw clamp

Those knobs pass a 3.0 mm = 1/8 inch rod, similarly sourced. Inexplicably, one clamp expected no more than a 7/64 inch rod; a brief introduction to Mr Drill Press persuaded it concerning the error of its ways.

I should have made the handles distinctively different, because they’ll get mixed up in the box of vises & clamps. Next time, fer shure!

The Tommy Bar handles use the same solid model as the Sherline Tommy Bars, with hole diameters as noted. Cyan PETG is definitely easier on the eye than red PLA, although it does fade into the background clutter around here.

2017-10-12

Vacuum Tube Lights: Duodecar Rebuild

You’ll recall the LED atop the 21HB5A tube failed, shortly after replacing the bottom LED and rewiring the ersatz plate lead, which led me to rebuild the whole thing with SK6812 RGBW LEDs. So I printed all the plastic parts again, because the duodecar tube socket’s pin circle can fit into a hard drive platter’s unmodified 25 mm hole, then drilled another platter to suit:

The hole under the drill fits the 3.5 mm stereo socket for the ersatz plate lead, so it’s bigger than before.

I’ve switched from Arduino Pro Minis with a separate USB converter to Arduino Nanos with an on-board CH340 USB chip, because the fake FTDI chips on the converters are a continuing aggravation:

21HB5A base - interior — 21HB5A base – interior

Adding those wire slots to the sockets definitely helps tidy things up; the wires no longer need a crude cable tie anchoring them to the socket mounting screws.

I wanted to drive the LEDs from the A7 pin, rather than the A3 pin I’d been using on the Pro Minis, to keep the wires closer together, but it turns out that A6 and A7 can’t become digital output pins. So I used A5, although I may come to regret the backward incompatibility.

In any event, the 21HB5A tube looks spiffy with its new LEDs in full effect:

21HB5A with RBGBW LEDs - cyan violet phase — 21HB5A with RBGBW LEDs – cyan violet phase

I dialed the white LED PWM down to 32, making the colors somewhat pastel, rather than washed-out.

The Arduino source code as a GitHub Gist:

	// Neopixel mood lighting for vacuum tubes
	// Ed Nisley – KE4ANU – June 2016
	// September 2016 – Add Morse library and blinkiness
	// October 2016 – Set random colors at cycle end
	// March 2017 – RGBW SK6812 LEDs

	#include <Adafruit_NeoPixel.h>
	#include <morse.h>
	#include <Entropy.h>

	//———-
	// Pin assignments

	const byte PIN_NEO = A5; // DO – data out to first Neopixel

	const byte PIN_HEARTBEAT = 13; // DO – Arduino LED

	#define PIN_MORSE 12

	//———-
	// Constants

	// number of pixels
	#define PIXELS 2

	// index of the Morse output pixel and how fast it sends
	boolean Send_Morse = false;
	#define PIXEL_MORSE (PIXELS – 1)
	#define MORSE_WPM 10

	// lag between adjacent pixel, degrees of slowest period
	#define PIXELPHASE 45

	// update LEDs only this many ms apart (minus loop() overhead)
	#define UPDATEINTERVAL 50ul
	#define UPDATEMS (UPDATEINTERVAL – 1ul)

	// number of steps per cycle, before applying prime factors
	#define RESOLUTION 500

	//———-
	// Globals

	// instantiate the Neopixel buffer array

	Adafruit_NeoPixel strip = Adafruit_NeoPixel(PIXELS, PIN_NEO, NEO_GRBW + NEO_KHZ800);

	uint32_t FullWhite = strip.Color(255,255,255,255);
	uint32_t FullOff = strip.Color(0,0,0,0);
	uint32_t MorseColor;

	struct pixcolor_t {
	unsigned int Prime;
	unsigned int NumSteps;
	unsigned int Step;
	float StepSize;
	float Phase;
	byte MaxPWM;
	};

	unsigned int PlatterSteps;

	byte PrimeList[] = {3,5,7,13,19,29};

	// colors in each LED
	enum pixcolors {RED, GREEN, BLUE, WHITE, PIXELSIZE};

	struct pixcolor_t Pixels[PIXELSIZE]; // all the data for each pixel color intensity

	uint32_t UniColor;

	unsigned long MillisNow;
	unsigned long MillisThen;

	// Morse code

	char * MorseText = " cq cq cq de ke4znu";

	LEDMorseSender Morse(PIN_MORSE, (float)MORSE_WPM);

	uint8_t PrevMorse, ThisMorse;

	//– Figure PWM based on current state

	byte StepColor(byte Color, float Phi) {

	byte Value;

	Value = (Pixels[Color].MaxPWM / 2.0) * (1.0 + sin(Pixels[Color].Step * Pixels[Color].StepSize + Phi));

	// Value = (Value) ? Value : Pixels[Color].MaxPWM; // flash at dimmest points for debug

	return Value;
	}

	//– Select three unique primes for the color generator function
	// Then compute all the step parameters based on those values

	void SetColorGenerators(void) {

	Pixels[RED].Prime = PrimeList[random(sizeof(PrimeList))];

	do {
	Pixels[GREEN].Prime = PrimeList[random(sizeof(PrimeList))];
	} while (Pixels[RED].Prime == Pixels[GREEN].Prime);

	do {
	Pixels[BLUE].Prime = PrimeList[random(sizeof(PrimeList))];
	} while (Pixels[BLUE].Prime == Pixels[RED].Prime \|\|
	Pixels[BLUE].Prime == Pixels[GREEN].Prime);
	do {
	Pixels[WHITE].Prime = PrimeList[random(sizeof(PrimeList))];
	} while (Pixels[WHITE].Prime == Pixels[RED].Prime \|\|
	Pixels[WHITE].Prime == Pixels[GREEN].Prime \|\|
	Pixels[WHITE].Prime == Pixels[BLUE].Prime);


	printf("Primes: %d %d %d %d\r\n",Pixels[RED].Prime,Pixels[GREEN].Prime,Pixels[BLUE].Prime,Pixels[WHITE].Prime);

	Pixels[RED].MaxPWM = 255;
	Pixels[GREEN].MaxPWM = 255;
	Pixels[BLUE].MaxPWM = 255;
	Pixels[WHITE].MaxPWM = 32;

	unsigned int PhaseSteps = (unsigned int) ((PIXELPHASE / 360.0) *
	RESOLUTION * (unsigned int) max(max(max(Pixels[RED].Prime,Pixels[GREEN].Prime),Pixels[BLUE].Prime),Pixels[WHITE].Prime));
	printf("Pixel phase offset: %d deg = %d steps\r\n",(int)PIXELPHASE,PhaseSteps);


	for (byte c=0; c < PIXELSIZE; c++) {
	Pixels[c].NumSteps = RESOLUTION * Pixels[c].Prime; // steps per cycle
	Pixels[c].StepSize = TWO_PI / Pixels[c].NumSteps; // radians per step
	Pixels[c].Step = random(Pixels[c].NumSteps); // current step
	Pixels[c].Phase = PhaseSteps * Pixels[c].StepSize;; // phase in radians for this color

	printf(" c: %d Steps: %d Init: %d Phase: %d deg",c,Pixels[c].NumSteps,Pixels[c].Step,(int)(Pixels[c].Phase * 360.0 / TWO_PI));
	printf(" PWM: %d\r\n",Pixels[c].MaxPWM);
	}
	}

	//– Helper routine for printf()

	int s_putc(char c, FILE *t) {
	Serial.write(c);
	}

	//——————
	// Set the mood

	void setup() {

	pinMode(PIN_HEARTBEAT,OUTPUT);
	digitalWrite(PIN_HEARTBEAT,LOW); // show we arrived

	Serial.begin(57600);
	fdevopen(&s_putc,0); // set up serial output for printf()

	printf("Vacuum Tube Mood Light – RGBW\r\nEd Nisley – KE4ZNU – March 2017\r\n");

	Entropy.initialize(); // start up entropy collector

	// set up pixels

	strip.begin();
	strip.show();

	// lamp test: a brilliant white flash

	printf("Lamp test: flash white\r\n");

	for (byte i=0; i<5 ; i++) {
	for (int j=0; j < strip.numPixels(); j++) { // fill LEDs with white
	strip.setPixelColor(j,FullWhite);
	}
	strip.show();
	delay(500);

	for (int j=0; j < strip.numPixels(); j++) { // fill LEDs with black
	strip.setPixelColor(j,FullOff);
	}
	strip.show();
	delay(500);
	}

	// get an actual random number

	uint32_t rn = Entropy.random();

	printf("Random seed: %08lx\r\n",rn);
	randomSeed(rn);

	// set up the color generators

	SetColorGenerators();

	// set up Morse generator

	Morse.setup();
	Morse.setMessage(String(MorseText));
	MorseColor = strip.Color(255,random(32,64),random(16),0);

	PrevMorse = ThisMorse = digitalRead(PIN_MORSE);

	printf("Morse enabled: %d at %d wpm color: %08lx\n [%s]\r\n",Send_Morse,MORSE_WPM,MorseColor,MorseText);

	MillisNow = MillisThen = millis();

	}

	//——————
	// Run the mood

	void loop() {

	if (!Morse.continueSending()) {
	printf("Restarting Morse message\r\n");
	Morse.startSending();
	}
	ThisMorse = digitalRead(PIN_MORSE);

	MillisNow = millis();
	if (((MillisNow – MillisThen) >= UPDATEMS) \|\| // time for color change?
	(PrevMorse != ThisMorse)) { // Morse output bit changed?

	digitalWrite(PIN_HEARTBEAT,HIGH);

	if (Send_Morse && ThisMorse) { // if Morse output high, overlay flash
	strip.setPixelColor(PIXEL_MORSE,MorseColor);
	}
	PrevMorse = ThisMorse;
	strip.show(); // send out precomputed colors

	boolean CycleRun = false; // check to see if all cycles have ended
	for (byte c=0; c < PIXELSIZE; c++) { // compute next increment for each color
	if (++Pixels[c].Step >= Pixels[c].NumSteps) {
	Pixels[c].Step = 0;
	printf("Cycle %d steps %d at %8ld delta %ld ms\r\n",c,Pixels[c].NumSteps,MillisNow,(MillisNow – MillisThen));
	}
	else {
	CycleRun = true; // this color is still cycling
	}
	}

	// If all cycles have completed, reset the color generators

	if (!CycleRun) {
	printf("All cycles ended: setting new color generator values\r\n");
	SetColorGenerators();
	}

	for (int i=0; i < strip.numPixels(); i++) { // for each pixel
	byte Value[PIXELSIZE];
	for (byte c=0; c < PIXELSIZE; c++) { // … for each color
	Value[c] = (Pixels[c].MaxPWM / 2.0) * (1.0 + sin(Pixels[c].Step * Pixels[c].StepSize – i*Pixels[c].Phase));
	}
	UniColor = strip.Color(Value[RED],Value[GREEN],Value[BLUE],Value[WHITE]);
	strip.setPixelColor(i,UniColor);
	}

	MillisThen = MillisNow;
	digitalWrite(PIN_HEARTBEAT,LOW);
	}

	}

view raw TubeMorse.ino hosted with ❤ by GitHub

2017-03-22

Tag: Sherline

Vacuum Tube LEDs: 21HB5A on a Guilloche Platter

LinuxCNC 2.7 vs. Logitech Joggy Thing

T-shirt Shop Rags

Plotter Grit Wheel Bushings

NEMA17 Motor and Bearing Mounts

More Tommy Bar Handles

Vacuum Tube Lights: Duodecar Rebuild