Sieg X1 Micro Mill Drill

I have been looking for tools that can help create (small) mechanical parts from metals & plastics. A small milling machine may fit the bill.
Looking for a suitable milling machine I searched the internet for information.
After checking my budget, I found my options were limited.

Proxxon MF70 Sieg X1 Micro Mill comparison table
Proxxon MF70 Sieg X1 Micro Mill
Speed 5,000 – 20,000 rpm 100 – 1000, 100 – 2000 rpm
Taper / Collet sizes 1.0 – 1.5 – 2.0 – 2.35 – 3.0 – 3.2 mm collets MT2
Table Size 200 x 70 mm 240 x 145 mm
X-Y Travel 134 x 46 mm 180 x 90 mm
Vertical Travel 70mm 30mm (fine) / 230 mm (coarse)
Overall size 130 x 225 x 340 mm 430 x 355 x 690 mm
Max. Power 100 W 150 W
Volts 220 – 240 V, 50/60 Hz. 220 – 240 V, 50/60 Hz.
Weight 7 kg 32 kg

There’s a lot of information available for DIY-converting these manual machines to CNC  (Computer Numerical Control), plenty of people have done so succesfully and documented their efforts in great detail. If you’re still operating it by hand, which is a good way to get familiar with it, make sure to read this guide on adjusting the X1 properly.

How did I choose my machine?


The MF70 is the lighter & smaller machine of the two, with much less weight (7 kg) and little less motor power (100 W). It does have a much higher spindle speed. This allows it to use much smaller diameter milling bits (1.0 to 3.2 mm shank with the collects I found available) and makes it suitable for fine work, like juwelry and model building.

The X1 has a slightly more powerfull motor (150 W), and with it’s MT2 taper it takes Morse Taper 2 collets for any diameter mill bits. The X1 allows for larger parts to be made because of it larger table travel, nearly twice in the Y-axis. The weight difference suggests it to be of a more sturdy construction as well, so for tougher jobs the X1 would be better suited. The Z-axis of the mills are different in design.

The MF70 uses a single handle to adjust the height of the toolhead. The X1 has a seperate handle for the coarse and fine mechanism. The coarse mechanism is located near the top and back of the machine. It adjusts the overall position of the spindle motor used a handle like the ones for X and Y. The fine mechanism can be operated in 2 ways. The larger handle at the right operates like your average drill-press.

You press down, the drilling head moves down and a hole is drilled. A mechanical switch opposite the handle engage the smaller handle at front. This allows you to much more finely adjust the Z position of the tool. Both of these 2 ways have a limit of ~30mm. The coarse Z-adjustment at the top/back allows for ~230mm of travel.

Availability of the mill

Proxxon is a fairly well known brand in The Netherlands.

A few retailers in Amsterdam sell their products:

  • IJzerhandel van Kalken
  • IJzerhandel Fillet
  • van den Berge IJzerwaren

Online you can buy the MF70 at Buitelaar sells it too.

Sieg, on the other hand, remains completely unknown and unmarketed. The only retail store in the The Netherlands where I could find a (rebranded) Sieg machine is Buitelaar.

Since they had a good price, I bought it there, and picked it up.

Abroad it’s sold by various hardware stores:

  • United States : Harbor Freight, Grizzly, Micro-Mark, Homier, Smithy, Bolton
  • United Kingdom : Arc Euro Trade, Axminster, MachineMart.
  • Germany : Rotwerk, Jeddeloh, Ar-Tec
  • Australia: Jet

Some of the stores no longer sell the X1 series, but start at the largers models like the X2, or the slightly different SX1 (tiltable column).

If you know about retail- or webstores that sell the X1, SX1 or X2, let me know!

Availability of cnc conversion-kits

If you have chosen a mill there might be complete kits available for your machine, including motors, moounts, drivers and a controllerboards. Buying a kit will save you an infinite amount of time on the mechanical construction , but takes away the fun of building it yourself.

The availability of CNC conversion kits for the MF70 like the one sold by USOVO and KDN Tool make it a temping offer. These kits make it really easy to transform a manual millling machine to a CNC operated one. If you plan to do the conversion yourself, be prepared to spend a great deal of time on it.

For the X1 a few kits are available too. Again KDN Tool offers one, and CNCFusion another one.

Little machine shop sell a belt drive kit as well as several accessoires, add-ons and table extensions.

Now, how to go about converting it into this little mini-factory you’ve always wanted? The basic plan seems simple, and it is.

Buy a small milling machine
Add a motors where the handles are now
Have a computer control these motors.
Instruct the computer to make parts.
Done! (Have your coffee now!)

In practice there is a bit more to it.

A milling machine. Find one of your choice. Small, big, somewhere in between. Buy as big as you need and can afford.
Motors. (steppermotors or servomotors are most commonly used.) Servo motors are considered high-end, steppermotors more low-end. This has to do with the feedback these motors are capable of giving to their control circuitry, their precision, power, etc. Price is a factor too, a steppermotor-setup is usually a less expensive than a servo-motor setup.
Drivers. These bits provide the control and the power to the motors. Sometimes they come as a single part to drive several motors, with other types you need one for each motor.
Controller board. The parallel-port of a computer can be used oftentimes. It can convey enough I/O signals to control 3 motors (X/Y/Z),  3 limit-switches (X/Y/Z) and an emergency stop. Nowadays slowly more USB CNC controllers are appearing. Usually they have more I/O so you can control a coolant setup-controller, spindle-speed controller if available too or a hand-held pendant controller. I’ve compiled a list of various controllers here (red: not quite yet).
Various mechanical parts. You will need to