Grinding arbor for Unimat SL/DB

Unimat SL/DB grinding arbor. Photo from the Internet

Arbor’s lenght 18 + grinding tool + 3 + 5.2 (bolt head) mm. Thread length on bolt 13,2 mm, M12x1.

Thread on the arbor M12x1, continuous, last 5 mm toward the headstock are bored to ~14 mm.

Holder diameter 15 mm, holder lip 3 mm. Max diameter 28mm.


Safety first

Right shoe failed. Skid marks on the wall, the ladder is out of service.

Eclipse, Arduino and STM32

Mkay, let’s switch from Arduino IDE to some more user friendly.

I need Arduino, PHP, Python and i woukl like to switch to STM32 ‘Blue pill” instead of AVR core.

Seems like Eclipse community has developed some support on Arduino: need to mention Sloeber to bringing more pleasant UX to Arduino community. STM32duino community has an nice wiki post on installing Sloeber on Eclipse, yet it’s not up to date right now:

  1. Arduino plugin JSON link right now resides in instead of
  2. You don’t need to update to CDT 9.1, as Eclipse has CDT 9.4
  3. You do need to install support for SAM boards from “Arduino”->”Preferences”->”Platforms and boards”, mainly “Arduino SAM Boards (32-bits ARM Cortex-M3)”
  4. The GNU C/C++ compiler, provided with SAM boards is quite oldish, IMHO – it tells “4.8.3-2014q1”. I have a GNU Arm Embedded Toolchain in “C:\Program Files (x86)\GNU Tools ARM Embedded\7 2017-q4-major” and it seems quite legit to replace “A.RUNTIME.TOOLS.ARM-NONE-EABI-GCC.PATH” projec’t variable with the path above and the compilation is performed using the GCC v7 binaries.

Right now i have some older Arduino sketches that I would like to port to STM32: I like the on-board USB, increased pin count and the idea of J-Link debugger.

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Woodpecker 2.8 GRBL board and ISP connector

In the case you heed to to upgrade the Woodpecker CNC control board, you will have to overcome some issues.

First one, the firmware upgrade via USB is almost(?) impossible, due to the CH340 chip between USB socket and Atmeg328.

Second one, the ISP header IS present on the PCB, but is has 1,27mm (0,05″ or 50 mils) pitch. Usual ISP connectors comes to 2,54 mm (0,1″ or 100 mils) pitch. Read the rest of this entry »

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My GRBL settings for 3018 CNC DIY machine

My settings for 3018 DIY CNC machine with Woodpecker’s control board and GRBL 0.9j.20150930. Note the feed rate and acceleration on axes.

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Rant: GIT repositories

If unable to push commits, use git clone ssh:// instead of proposed git clone ssh:// u-USERNAME-PROJECTNAME



LCM-WM002 is a 16×2 LCD display, coming from a “refurbished” equipment. To be true, the equipment was a HP 5000 / 5100 laser printer, and the LCD has a bezel and a PCB with buttons attached, named ESU19516, part number RG5-5438. Read the rest of this entry »

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Rant on Apache2

Recently I was trying to move my sites to SSL – for various reasons.
The test site went fluently, while the work machine refused to serve SSL content. While testing with ‘wget’, the error I received was

GnuTLS: An unexpected TLS packet was received.

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Rant on AVR ISRs

Once you define an ISR bit in the TIMSKx, the appropriate ISR must be attached.

Lost almost a day on non functioning serial port, until stumbled upon the post in

So, when copypasting

TIMSK1 |= (1 << TOIE1) | (1 << OCIE1A);

be sure to define both
ISR(TIMER1_OVF_vect) {



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Current token in Arduino’s ArduinoSerialCommand

Ever played with ArduinoSerialCommand? Nice library, but it lacks the possibility to retrieve current command. This possibility is waiting in the pull request for a long time, so if you deadly need it – merge it by yourself.

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