Proxxon MF 70 and LinuxCNC – Part IV

Great, the 40 GB Seagate Barracuda IDE HDD is dead. I had too many bad sectors while I was trying to install LinuxCNC, anyway. I’ll have to get another IDE HDD and some more RAM’s tomorrow.

In the meantime, I opened one of the unused HY-DIV168N-3.5A Stepper Motor Drivers to figure out the capacitor value at pin 7 (Cosc) of the TB6560AHQ in it.


It is not a 1000 pF like it is in those Blue PCB single board drivers, as stated in a text here, but it’s a 330 pF. This should give us 130 Khz oscillating frequency, and a minimum clock pulse width of 30 us, according to the datasheet.

Where the 330pF capacitor is…

In the Stepper Configuration Wizard…

Step Time: How long the step pulse is on in nano seconds (Mark of Pulse Width -> 30 us = 30000 ns).
Step Space: Minimum time between step pulses in nano seconds (Space of Pulse Width or Period -> 1000000 / 130000 = 7692.31 ns).

6N137 optocoupler delay is negligible, if we round up the Step Space to 7800 ns. I don’t know if I need the speed gained (500 ns to 50 ns) by changing the diodes to ultra-fast ones yet (also stated in the same text).

I have no idea about Direction Hold or Setup values, some people set it to 20000.

I’ll test all of these with my DSO tomorrow.

I may change that to 100pf for 3 times the speed, but the datasheet states that it was not tested in production. Still a future plan for experimental purposes, maybe then it could be worth changing the diodes, too.

Table travel values should be…

X = 134 mm
Y = 46 mm (crap)
Z = 80 mm

I have been using the drivers at half step setting. I think, I may move up to 1/16 with these settings.

I’ll have to shop for some milling bits and brass on Saturday :)

Proxxon MF 70 and LinuxCNC – Part III

Finally tested the setup last night with temporary motor cable connections.

The X axis motor has problems at 2:34 and 3:10 (does anyone know the reason, check out the motor sound going crazy), and the table wobbles a bit. I didn’t exceed the table limits. Haven’t touched the gibs yet, and forgot to oil the X axis of this long forgotten mill. I’m also suspicious about the motor timings I made up.

I should get the timing capacitor value on the PCB, and refer to the TB6560 datasheet (page 10).

I think I’ll finalize the hardware tonight and start working on the calibration, etc. for a first run with the spindle on.

Proxxon MF 70 and LinuxCNC – Part II

I didn’t much today, other than adding a DB-25 extension cable to connect the interface card to the outside of the box, and mounting the female connectors of the motors on the box and wiring them.

Four Pin
Four-pin female (not really) motor connectors.

The DB-25 extension was somehow faulty (chopped off in the picture), since when I tested the whole system with LinuxCNC to observe the LED’s on the drivers and the interface board, the result was a failure (only one LED blinking weirdly). When I directly connected the cable to the box, all was fine :)

Inside of the electric box after all the cabling is finished.
Motor connectors.
Motor connectors.

Tomorrow I’ll finish the cables for the stepper motors, and fix the DB-25 extension cable.


Proxxon MF 70 and LinuxCNC – Part I

Today my friend Onur and I started working on our little CNC project. Since he currently has no use for it, Onur offered to leave his MF 70 in my workshop indefinetely, so we can convert it to a small CNC and use it for manufacturing small parts .

MF 70 with motors mounted, standing on the electric box which will house the electronics.

I have been planning on converting my Optimum BF20L to CNC, but I think I will start with Onur’s MF 70 to gain some experience first.

I had a couple of HY-DIV168N-3.5A Two Phase Hybrid Stepper Motor Drivers, and a couple of NEMA 23 stepper motors (salvaged from old printers, details later) laying around, and later on I got a HY-JK02-M 5-axis Interface Board from Hong Kong for $15.

I found an old PC (PIII 800Mhz with 128MB of RAM, and a Trident Blade 3D Video Card) for free, and added a second hand 17″ LCD monitor, 256MB more RAM, and a wireless KB/Mouse set. Installing LinuxCNC 2.6 from a DVD was problematic, so I installed LinuxCNC 2.5 from a CD (I think the 40GB HDD is a bit too old).

I also purchased a CNC-made aluminum mounting kit, with polyamide couplings, for the motors for $49. We mounted the motors today. I mounted the interface board, stepper drivers, and the 24V 8.3A switching power supply to the metal plate of an electric box I had purchased for another project. I will connect cables with male connectors to the motors, and mount the female connectors on the box for easy operation later.

Interface board, stepper drivers, 24V to 5V DC-DC converter, and PSU.

After a long installation, the distribution was working fine. However, when I started LinuxCNC, it crashed immediately. I did a little research, and the solution is below worked.

in /etc/default/grub, change



GRUB_CMDLINE_LINUX_DEFAULT="quiet splash lapic"


I also changed the Driver section for my Trident Blade 3D video card to Driver “vesa” in /etc/X11/xorg.conf, which I had to create manually with sudo Xorg -configure, after stopping gdm from another terminal.  Maybe it  wasn’t really necessary, I will test and see soon.

Mach 3? No, thanks :)
Mach 3? No, thanks ;)

Next step is connecting the motors and configuring LinuxCNC.

Ubuntu’da Turkcell Vinn Kullanımı

Internet’te bu konuda bir sürü sorun ve çözüm gördüm ama Türkçe olarak bu yolu deneyen görmedim. Bendeki ZTE MF667 USB 3.5G modemi bilgisayar direk Kablolu Bağlantı olarak görüyor. nm-tool gibi bir programla bir terminal emülatöründen (terminator favorimdir) arabirimlere bakın. Orada  Driver: cdc_ether satırını içeren cihazın Gateway adresini (mesela Firefox’a falan yazın. Doğrudan Windows Vınn yazılımında gördüğünüz Vınn ekranına gideceksiniz. Girin oraya PIN kodunuzu ve bağlanın. Sayfayı kapasanız da hattasınız. Daha sonra aynı adresten tekrar girip bağlantıyı kesebilirsiniz.

Ubuntu 14.04


Now I must sleep…

I will be posting my thoughts, projects, experiences and dreams here. In Turkish and in English…

The time is nigh…


This blog is stored on a VPS in NY, running Ubuntu 12.04 LTS.