Stepper Motors and Controller

A Taig NEMA 23 stepper-motor mount screwed onto the lead screw boss.
The ring clamps the split housing to grip the fine threads.

Each coupler was modified to include an 8-32 set screw (with a green nylon locking insert) that engages the shaft flat.
The tips were diamond ground flat. The set screw will spread the slit so I tighten the clamping cap-head bolt first.

Stepper motors shown with a Taig NEMA 23 mount & couplers.
305oz-in unipolar rating, 4.2v, 3A, 200 steps/revolution, 3.2mH.
Dual ¼" diameter shafts (with flats) are ⅞" & ⅝" long.

Eight-wire stepper motor leads with 6-pin (crimped & soldered) Molex connected cables.
Black protective sheath removed from one of the stepper motors. Pieces of heat shrink hold the wire bundles.
The stepper-motor connectors can be plugged directly into the controller box without the cables.

My Mach3 stepper setup for X, Y, & Z-axes: 200 steps/motor rev x 4 (¼ stepping) x 20 TPI lead-screw pitch = 16,000 steps/inch.
These 305oz-in steppers are quite powerful given the scale of the Taig machine. They allow good split-nut clamping pressures &
fast transition speeds especially when considering the relatively short distances involved & working in metal.

Note the small gap in-between the couplers. Attached a knob to the motor's shaft to assist in aligning the coupler pins.
Screw the mount in & out to adjust the coupler gap. Do not over tighten the motor clamping plate & ring.
The ring set screw is 90º off the collar's slit.

CNC rotary table with 305oz-in stepper motor. I see no difference in the amount of backlash between this & their regular table.
Note the addition of a guide plate on the back (or front) edge of the mounting plate. Also see other small & large rotary tables.
My stepper setup for Mach3's fourth, A-axis: 200 steps/motor rev x 4 (¼ stepping) / 5º/table rev = 160 steps/º

Tram the rotary table face by performing adjustments both horizontally & vertically.

Milling the panel on the RF-25 mill. The open-slot area slightly exceeds the original, 10-hole design area.

The pin out terminal strips pass through & can be directly connected to the PCB inside the case.

Unpopulated HobbyCNC Pro, 4-axes stepper-motor controller PCB.

Populated PCB. 4-40 threads were tapped for the heat-sink screws. Heat-sink compound was thinly applied the driver chips.

Note (4) metal tubes were used to increase fan mount rigidity. A green LED was incorporated into the 2KΩ bleeder-resistor circuit.
Molex receptacles are snapped into the enclosure's back panel. An extra 120VAC cord strain relief clamp was also added.
Note the terminal block connections passing through the rear panel. I leave all J4 jumpers ON so the motors do not idle down.

When powered down, the green LED dims as the current bleeds off. It extinguishes in a few minutes.

Extra rubber feet were attached directly to the 8 lbs. transformer to eliminate any case distortion.

The horizontal air vents have a nice look.

Table shows the pin outs for the HobbyCNC PCB motors & other Mach3 functions.

PIN OUTS
LPT1	FUNCTION
1 - Output	-
2 - Output	X direction
3 - Output	X step
4 - Output	Y direction
5 - Output	Y step
6 - Output	Z direction
7 - Output	Z step
8 - Output	A direction
9 - Output	A step
10 - Input	Limits
11 - Input	-
12 - Input	-
13 - Input	E-Stop
14 - Output	-
15 - Input	-
16 - Output	spindle motor
17 - Output	air / mist / vacuum
18 - 25	Ground

LPT1 OUTPUTS: 1-9, 14, 16, 17
LPT1 INPUTS: 10, 11, 12, 13, 15

The PCB pin-outs (10, 11, 12, 13, 15, have pull-up resistors & 1, 14, 16, 17 do not, plus GND) are connected to the back-panel terminal blocks.
The pull-up resistors interfered with the C1 breakout board control logic so I removed them from the stepper-motor circuit.
These I/O can be used as extension/access to an enclosed breakout board. Note the strain relief clamp at the power cord entry (lower right).

These pin out labels were added so they could be seen when the unit is underneath the bench.