[ REVTURN ]

A touch-screen CNC lathe controller on an ESP32

ProtoTRAK / Fanuc style conversational control, built into the grblHAL firmware and served from the lathe itself. Open it on a phone, a tablet by the machine or a PC. No app, no sender, no cloud.

Buy one preflashed: $125 Website Source on GitHub

The REVTURN RUN screen with live backplot

[ WHAT IT DOES ]

CONVERSATIONAL CYCLESFace, turn (taper, chamfer, radius), bore, thread, groove / part-off, peck drill, polygon flats, index. GO previews, GO again cuts.

THREADS WITHOUT AN ENCODERThe chuck is a stepper: Z and C move in lockstep, so the pitch is exact.

SPINDLE OR C AXISRPM under M3 / M4, or a rotary C axis in degrees for indexing and polygons.

PROGRAMS + BACKPLOTChain cycles and g-code, import Fusion 360 lathe posts, watch the live backplot with set and actual feed and rpm.

HOLD / GO / STOPAlways on screen, on every phone or tablet at once. Feed, spindle and rapid overrides.

EVERY SETTINGAll 128 grblHAL settings in the same look, with help text, search, backup and reboot.

TOOL TABLET1 to T8 with touch-off and stroke limits, shared by every screen.

OPEN SOURCEFirmware, screen, tools, printed parts and every FreeCAD source on GitHub, all GPL v3 or later with attribution (keep the credit: REVTURN by JMSCNC).

[ THE SCREENS ]

DRO screen — DRO: big readout, jog pad, zero keys, spindle slider.

Threading cycle — CYCLES: threading with a toolpath preview.

Program editor — EDIT: programs made of cycles and g-code.

Tool table — SET UP: tool table, tap a T to use it.

Settings — SETTINGS: every grblHAL setting, with inch conversions.

Turning cycle — Turning with taper, chamfer and radius.

[ BUY ONE ]

The REVTURN controller board: an ESP32 on a screw-terminal breakout board, wired up on the REVTURN lathe

REVTURN controller board, preflashed

$125 + $9 shipping (US)

A bare ESP32 DevKit (WROOM-32, 4 MB, USB) on a screw-terminal breakout board, flashed with the REVTURN firmware and screen and tested before it ships. Set up as a lathe: X, Z and the chuck as spindle or C axis. Wire it to your step / dir drivers, power it up and open the screen.

Not included: stepper drivers, motors, power supply or the lathe.

BETA: the conversational cycles have not been cut-tested on real stock yet. Preview first (the first GO only previews), run DRY RUN in the air, set your stroke limits and turn LIMITS on, and do a scratch pass before threading to check the thread direction.

Signal	Pin
X step / dir	`GPIO 16 / 17`
Z step / dir	`GPIO 21 / 22`
C step / dir	`GPIO 18 / 19`
Stepper enable	`GPIO 23`
PWM spindle / enable	`GPIO 4 / 13`

Buy one: $125

[ THE LATHE ]

REVTURN grew up on a 3D-printed junk-bin mini lathe: rails from a 3018 upgrade and a scrapped printer, an AliExpress headstock, a Cricut stepper and a NEMA 23 on the chuck. Every printed part is an original FreeCAD design with its source on GitHub.

[ BUY ME A COFFEE ]

Like REVTURN? Keep it turning.

REVTURN is free and open source. A coffee keeps the designs and the updates coming.

☕ Buy me a coffee

Website · GitHub · Buy a board · Buy me a coffee
REVTURN © 2026 JMSCNC · Rev. J. Money. Built on grblHAL (© Terje Io and contributors, GNU GPL v3).