The REVTURN controller board: an ESP32 on a screw-terminal breakout board, wired up on the REVTURN lathe
The REVTURN RUN screen: one-line DRO with set and actual feed, overrides, live backplot and the program
The REVTURN DRO screen with jog pad, zero keys and spindle slider
The REVTURN threading cycle with a toolpath preview
REVTURN on a phone with HOLD, GO and STOP pinned at the bottom
The REVTURN SETTINGS screen showing grblHAL settings with inch conversions
The REVTURN SET UP screen: T1 to T8 tool table with touch-off
The REVTURN program editor with cycle and g-code steps

REVTURN CNC Lathe Controller: ESP32 Screw-Terminal Board, Preflashed

$125.00

The brains of a CNC lathe, ready to wire: an ESP32 on a screw-terminal breakout board, flashed with REVTURN (grblHAL) and tested. Wire it to your step / dir drivers, join it to your WiFi, and run your lathe from any phone, tablet or PC: conversational cycles, threading by Z and C sync, programs, live backplot, HOLD / GO / STOP on every screen.

Drivers, motors and power supply not included.

BETA: the conversational cycles are new and have not been cut-tested on real stock yet. Always 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.

More about REVTURN · Website and screenshots · GitHub

SKU: JMSCNC-REVTURN-ESP32-BOB Categories: ,

What you get

  • ESP32 DevKit (WROOM-32, 4 MB flash, USB) on a screw-terminal breakout board
  • REVTURN firmware (grblHAL with the REVTURN changes) and the REVTURN control screen, flashed and tested
  • Set up as a lathe: X (cross slide, in diameter), Z (carriage) and the chuck as a stepper spindle (RPM) or a rotary C axis (degrees)

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

The REVTURN screen

  • Served by the board over WiFi: open it on a phone, tablet or PC. No app, no PC sender, no cloud. Find it at revturn.local.
  • Big DRO, jog pad and keyboard jog, ZERO keys, spindle slider
  • Conversational cycles: face, turn (taper, chamfer, radius), bore, thread, groove / part-off, peck drill, polygon flats, index. GO previews the toolpath, GO again cuts.
  • Threading without an encoder: Z and C move in lockstep
  • Programs made of cycles and g-code, Fusion 360 lathe post import, dry run
  • Live backplot, set and actual feed and rpm while running
  • HOLD / GO / STOP always on screen, feed / spindle / rapid overrides, alarms in plain words
  • T1 to T8 tool table with touch-off and stroke limits
  • SETTINGS: every grblHAL setting with help text, search, backup and reboot
  • Many screens at once; any of them can HOLD or STOP

Beta: test the cycles first

The conversational cycles are new. Their g-code is checked by automated tests and every axis has run on the REVTURN lathe, but no cycle has cut real stock yet. Until they have:

  • Always look at the preview: the first GO only previews the toolpath, the second GO runs it.
  • Run each cycle with DRY RUN on first: it cuts air with Z lifted and the spindle off.
  • Set your real travel as stroke limits in SET UP and turn LIMITS on.
  • Before threading, do a light scratch pass to check the thread comes out the right hand.
  • Keep a hand near HOLD and STOP.

Wiring

Signal ESP32 pin Goes to
X step / dir GPIO 16 / 17 Cross slide driver
Z step / dir GPIO 21 / 22 Carriage driver
C step / dir GPIO 18 / 19 Chuck driver (spindle or C axis)
Stepper enable GPIO 23 Driver enable inputs (shared)
PWM spindle / enable GPIO 4 / 13 Optional router or live tool
Limit inputs (spare) GPIO 32, 33, 27 Not wired by default

Works with common step / dir drivers (it runs TB6600 and DM542T class drivers on the REVTURN lathe). Every machine is different: after wiring, set steps per mm, max rates and acceleration for your screws, belts and motors in SETTINGS. The REVTURN lathe’s own settings are on GitHub as a starting point.

Open source

The firmware is grblHAL (© Terje Io and contributors) with the REVTURN changes, under the GNU GPL v3; the source is on GitHub, so you can always rebuild and reflash it yourself. REVTURN by JMSCNC, © 2026 Rev. J. Money / JMSCNC: firmware changes, screen, tools and printed parts are GPL v3 or later with attribution (keep the credit).

Additional information

Weight 0.25 lbs

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