Hex key sizes

Use 2 mm for the M3 BHCS/FHCS. Use 3 mm for the M5 BHCS/FHCS. Use 5 mm for the M6 SHCS. You use the 2 mm and 3 mm most, so get a good key of each.

Load the T-nuts first

Before you square the frame, slide every T-nut into its slot.

Direction convention

Top, bottom, left, and right throughout this manual refer to this view.

Short extrusion on top

Put the short extrusion with the 4 slide-in T-nuts on top.

Counterbores face out

Turn the counterbored ends of the long extrusions outward. Align each counterbore with the end hole of the short extrusion.

Square before final tightening

1. Drop each M6×20 SHCS through the counterbore into the end hole of the short extrusion. 2. Tighten all 8 until snug. 3. Square the frame on a flat surface. 4. Tighten fully.

Reinforce the frame

One flat bracket reinforces each corner. 1. Put 2 M5×10 BHCS through the bracket. 2. Thread a drop-in T-nut loosely onto each. 3. Put the bracket with its nuts into the frame corner. 4. Tighten both screws.

Feet point down

The bumpers are the feet of the machine. Install them under the four corners of the frame.

Bumper screws

If the bumpers came with their own screws, use those screws. They are the right size.

Center screw and nut first

Put the M5 square nut and the M5×10 BHCS into the middle counterbore first. The idler stacks block access to it later.

Check the idlers

After you install the idlers, make sure that each idler turns freely.

Flat face toward the screw

Put each square nut in with its flat face toward the screw.

If a side nut does not go in

The print can leave powder in the pocket. If a side square nut does not go in, clear the pocket with a small screwdriver or a pin.

Two attachments to the frame

The middle M5 screw threads into a slide-in T-nut in the extrusion slot. The flat bracket bridges the idler mount and the frame. On the bracket, the longer M5×12 BHCS threads into the captive square nut of the idler mount. The M5×10 BHCS threads into the drop-in T-nut in the extrusion slot.

2 mm gap to the corner flat bracket

Put the idler mount 2 mm clear of the horizontal flat bracket at the frame corner.

Each idler stack is 18 mm

The idler is 8.5 mm, the spacer 9 mm, a shim 0.5 mm. Use shims and spacers to bring every idler stack to 18 mm.

Spacer must total 9 mm

The spacer is 9 mm tall. If you cannot buy a 9 mm spacer, stack shorter spacers to a total of 9 mm.

Long screw into the idler mount

Split the screws as at the left idler mount. M5×12 goes into the idler mount, M5×10 into the extrusion slot.

Match the left idler mount's gap

Set the same 2 mm gap as at the left idler mount.

Motor A idler on the lower plane

This idler carries the Motor A belt. It has no spacer, so it rides on the lower belt plane.

2 mm gap to the corner flat bracket

Put this idler mount 2 mm clear of the horizontal flat bracket at the frame corner too.

Motor B idler on the upper plane

This idler carries the Motor B belt. The 9 mm spacer lifts it onto the upper belt plane.

Match the left idler mount's gap

Set the same 2 mm gap as at the left idler mount.

Note the connector direction

Make sure that the motor connector faces as shown. That direction sets the wiring clearance later.

Spacer height for Motor A

The spacer of Motor A must be 8 mm tall.

Tighten in a cross pattern

1. Thread all 4 motor screws in by hand. 2. Tighten opposite corners in pairs. This pulls the motor flat against the bracket.

Motor A

The left motor is Motor A.

Do not fully tighten the screws

Tighten until snug. After you tension the belt, tighten fully.

A taller spacer here

The spacer of Motor B must be 12 mm tall.

Right motor mirrors the left

Install it like the left motor, as a mirror image. The motor connector faces right.

Motor B

The right motor is Motor B, the mirror image of the left.

Do not fully tighten the screws

Tighten until snug. After you tension the belt, tighten fully.

Two heights

The Motor A belt and the Motor B belt sit at different heights. The pulley of Motor A (left) sits on the lower belt plane. The pulley of Motor B (right) sits on the upper belt plane. Slide each pulley along its motor shaft to its plane.

Set screws

1. Tighten one set screw onto the D-flat of the shaft. 2. Tighten the other.

Threadlocker

Make sure that the pulleys and idlers are aligned. Then apply threadlocker to every set screw. A loose pulley makes the motion inaccurate. It is the most common issue users report. You can also apply the threadlocker after you install the belts.

Install the carriage

Some carriages ship on a plastic dummy rail. Do not take the carriage off it. The balls can fall out. 1. Align the dummy rail with the end of the rail. 2. Slide the carriage from the dummy rail onto the rail.

Build two Y rails

The Y axis uses two identical rails.

Clean and grease the rails

MGN9H rails ship coated in anti-rust oil. Before you install the rail, wipe the oil off. Put fresh grease on the carriage so that it runs smoothly and lasts longer. Keep the rail away from water at all times.

Load the T-nuts first

1. Thread an M3×8 BHCS into every hole. 2. Thread a drop-in T-nut onto each screw tip so that it hangs. 3. Lower the rail onto the extrusion so that the T-nuts drop into the slot. 4. Tighten the screws until snug.

Straight side toward the motor

The left and right joints are mirror images. Install each joint with its straight side toward the motor.

Tighten in a cross pattern

1. Thread all 4 screws in. 2. Tighten opposite corners in pairs. This pulls the joint flat against the carriage.

Load the X beam T-nuts first

Slide the 2 M5 T-nuts in, one from each end.

Check the X beam

Slide the X beam along the Y rails by hand. If it binds, realign the Y rails.

Be patient

1. Tighten a few of the Y rail screws until snug. 2. Slide the X beam and feel the resistance. 3. Move the Y rails slightly. 4. Slide the X beam again. 5. When the beam slides freely, tighten the Y rails from the center screw outward. This can take a few minutes.

X rail

Install this rail like the Y rails. 1. Thread the screws in so that the T-nuts hang. 2. Lower the rail onto the extrusion so that the T-nuts drop into the slot. 3. Tighten the screws.

Check both axes

Make sure that the carriage slides smoothly along the X rail. Make sure that the whole beam still slides freely along the Y rails. If either binds, realign that rail. Then tighten it again.

Motor B idler on the upper plane

This idler carries the Motor B belt on the left joint. The 9 mm spacer lifts it onto the upper belt plane.

Use the correct hole

Install the idler in the top hole of the left joint.

Motor A idler on the lower plane

Use the toothed idler here, not the smooth one.

This idler carries the Motor A belt. It has no spacer, so it rides on the lower belt plane.

Motor A idler on the lower plane

This idler carries the Motor A belt on the right joint, in the top hole. It has no spacer, so it rides on the lower belt plane.

Motor B idler on the upper plane

Use the toothed idler here, not the smooth one.

This idler carries the Motor B belt on the right joint. The 9 mm spacer lifts it onto the upper belt plane.

Check all four idlers

Make sure that each idler sits in its correct hole.

Install the Motor A belt

The Motor A belt is a single open length. Both ends clamp to the X carriage. Keep the belt flat in one plane along the whole path. The teeth run on the pulley and the toothed idlers. The smooth back runs on the smooth idlers.

The clamp locks itself

1. Feed each belt end into the bottom slot of the clamp. 2. Loop it around the post. 3. Fold it back against itself so that the teeth mesh. The meshed teeth hold the belt with no extra fasteners.

Slide the motor to tension the belt

Keep the 2 M5 screws of Motor A snug, not tight. 1. Clamp both belt ends. 2. Slide the motor to tension the belt.

Clamp the belt, then install the clamp

Before you install the clamp on the X carriage, make sure that the Motor A belt sits in the bottom slot of the clamp.

Match the Motor B belt length

Before you put the Motor A belt into its clamp, cut the Motor B belt to the same length.

Install the Motor B belt

Route the Motor B belt on the upper belt plane. It must not cross the Motor A belt. Clamp both ends to the X carriage, the same way as the Motor A belt.

Check the belts

After you install both belts, slide the X carriage by hand through its full travel in every direction. The carriage must slide smoothly, with even resistance throughout. That resistance comes only from the motors. Make sure that nothing sticks, interferes, twists, or makes an odd noise. Make sure that the two belts stay on their separate planes.

Threadlocker

The pulleys are now aligned. If their set screws have no threadlocker yet, apply it now.

Belt tension

Tension the two belts equally. Even a small difference skews the gantry. To adjust the tension of a belt, slide its motor. Then tighten the motor bracket screws fully.

Pluck the belts

Quick check: 1. Slide the X carriage fully to the motor side. 2. Pluck the two marked belts with a finger. The two belts must feel and sound about the same. The same pitch means about the same tension.

75 Hz at 220 mm

Precise check: 1. Park the X carriage at the marked position. 2. Pluck each belt. 3. Read its frequency with a tuning app on your phone. 4. Adjust both belts to the same frequency, about 75 Hz.

Install the stylus tip

The solenoid has a nut on its bottom end. 1. Remove the nut. 2. If the stylus tip has an M5 female thread, install an M3 female-to-M5 male adapter on the solenoid. 3. Install the stylus tip.

Make the leads longer

Before you install the solenoid on the mount, make the positive and negative leads longer. Refer to Wiring — Extend the leads.

Ten hole pairs for height adjustment

The mount has 10 pairs of holes, 1 mm apart. Pick one pair now. Later you can raise or lower the stylus in 1 mm steps.

Route the power leads

1. Feed the +/− leads of the solenoid into the rectangular hole in the side of the mount, as shown. 2. Run the leads up and out through the rectangular hole at the top.

Ground the solenoid

1. Clamp the bare copper of the ground wire between the solenoid housing and the mount. 2. Tighten one of the 2 mount screws to clamp it. 3. Run the ground wire out through the other rectangular hole below to join the power leads.

Use 6 mm long bolts

Longer bolts can push against the coil and cause damage.

Install the solenoid on the belt clamp

Install the solenoid assembly on the belt clamp with 6 screws. To change the stylus height later, move the assembly to a different hole pair.

Build two cross-beams

Build two identical cross-beams for the bed.

Seat the bed on the beams

1. Lay the two cross-beams parallel, slotted faces up. 2. Lower the hanging T-nuts of the bed into the slots. 3. Tighten the screws.

Install the phone bed

It is far easier with the frame upside down. 1. Turn the frame over, underside up. 2. Slide the T-nuts of each beam into the slots under the frame.

Put the phone in place

Put a phone on the bed, against the top-left corner. Slide the X carriage over the whole screen. Make sure that the stylus tip reaches every part of the screen.

Set the solenoid height

Set the solenoid height so that the stylus tip just makes stable contact with the screen. If the solenoid is too low, it cannot pull in fully. The magnetic force is then too weak to hold the tip down. The tip springs back, so long presses and swipes fail. If the solenoid is too high, the tip cannot reach the screen, or the contact patch is too small.

Install the T-nuts

Thread 2 M5 FHCS into the T-nuts. Do not fully tighten until the next step.

Install the control board holder

Install it on the outer face of the top extrusion.

Install the control board

Use 4 screws with nuts. The figure does not show the 2 lower nuts.

Install the T-nuts

Thread 2 M5 FHCS into the T-nuts. Do not fully tighten until the next step.

Install the tube holder

Install it on the top extrusion, beside the control board. Its 4 mm hole holds the fixed end of the Teflon tube.

Rough length

Cut the tube to about 400 mm. It must reach from the tube holder to the X carriage at its farthest position.

Anchor the solenoid leads

Tie the solenoid leads to the tube holder with a cable tie. Otherwise the solenoid's travel shakes the lead wires at the control board terminals. Constant shaking works the contact loose, and then the solenoid no longer taps the screen.

PTFE vs FEP

Use either tube, PTFE (milky white) or FEP (clear).

Bind the wires with spiral wrap

Bind the solenoid's lead wires to the Teflon tube with spiral wrap along its full length. Do not put the wires inside the tube.

1/4-20, not metric

The SHCS and hex nut for the gooseneck are 1/4-20, the imperial tripod thread (≈ 6.35 mm). Do not use an M6 instead.

Imperial tools

The 1/4-20 SHCS takes a 3/16" hex key. The 1/4-20 hex nut takes a 7/16" (or metric 11 mm) open-end wrench. Needle-nose pliers also do the job. There is no need to buy tools for this.

Thread on the gooseneck

Thread the gooseneck's female end onto the stud until it is tight against the hex nut.

Thread on the camera

Thread the camera's 1/4-20 female thread onto the gooseneck's male stud until it stops against the collar.

Use the lower slot

Install the corner bracket in the lower slot of the right extrusion's outer face.

Orient the camera

Bend the gooseneck so that the camera points squarely at the phone screen. Align the sensor's long edge with the phone's long edge.

Check the camera

Make sure that the camera does not drift or wobble.

Route the USB cable

Tie the camera's USB cable along the gooseneck with cable ties, clear of the belt.

Power off first

While the board is powered, never plug in or remove a driver.

Note the orientation

Do not install a TMC2209 reversed. It can burn out when the power comes on. Before you press a driver into its header, make sure that its pin labels match the silkscreen.

Rule of thumb

Match colored to colored, black to black.

Heatsink

TMC2209 driver modules usually include a heatsink. Stick it on top of the driver chip.

Connections

The board uses standard GRBL axis outputs, remapped as follows: the X-axis stepper driver drives Motor B, the Y1-axis stepper driver drives Motor A, and the Spindle output drives the solenoid.

No polarity

Connect either solenoid lead to either Spindle terminal.

Motor cable connectors

The motor side is a 6-pin PH2.0 (2.0 mm pitch); 2 pins stay empty. The board side is a 4-pin XH2.54 (2.54 mm pitch). Each connector is keyed and fits in one orientation only. Align the key on the plug with the notch on the socket. Do not force the plug in.

Extend the leads

The solenoid's stock leads do not reach the control board. Splice lead wire onto both the 12 V and GND leads.

Keep the stock leads under 50 mm

Before you splice, cut the solenoid's stock leads back to 50 mm or less. The joints then sit clear of where the cable bends most. A joint that flexes with every gesture fatigues and snaps.

Stagger the joints

Stagger the two joints by about 10 mm. Do not put them side by side.

Connect the wires

Solder each joint. Cover each joint with heat shrink tubing. If you cannot solder, twist the wires together. Wrap each joint tightly with electrical tape.

Ground the stylus

The stylus rides on the solenoid's iron core. The metal return spring ties the core to the housing. Do not use the control board's GND. Ground the housing. The core and the stylus tip are then grounded too.

Why the ground matters

A capacitive screen senses a touch through capacitive coupling to ground. A finger works because the body is a large conductor tied to earth. An ungrounded stylus couples to earth too weakly. A tap then shifts the screen's charge distribution only slightly, and the phone registers the touch unreliably. A verified ground restores that coupling and steadies the touch.

How to ground the housing

Never put the ground wire into a wall outlet. Connect the housing to earth ground. The simplest option is a desktop PC chassis grounded through a three-prong outlet. Clip the wire to bare metal on the chassis. The chassis reaches earth through the mains and gives a stable reference.

Three wires

The solenoid has three wires: positive (+), negative (−), and ground. 1. Bind the ground wire into the bundle with the + and − leads. 2. Run the bundle up to the control board holder. 3. Connect + and − to the control board's Spindle terminals.