The Review of Sieg SX2.7 Milling Machine from Nigel Taylor

Oct 29, 2020

Thanks to Mr. Nigel Taylor that he shared us his article of the SX2.7 milling machine. If you are interested in his reviews, you could learn the his article from this link: He also provides us a Youtube link:

We also pick some of the content if you want to read it directly from here.

Finally got tired of the old milling machine and upgraded to a Sieg SX2.7 Milling Machine.

I had to split the machine into 2 parts to move it from the drive to the workshop. Even so it still hurt, total weight of the mill is around 95kg.

As you can see in the image on the left the column is bolted to the base with 4x 10mm bolts and 2x dowels that are used to align the post.

This immediately solves one of the issues that I had with the Amadeal mini mill in that the column wasn’t stiff enough. My simple measurements show that this Sieg SX2.7 static stiffness is roughly 4x higher than the mini mill.

The image to the right shows the column with the head still attached laying on it’s back.

The dowels work well aligning the column (a fairly fundamental engineering technique well executed here), plus as you can see on the base there are two machined pads with a lower rough cast central section on the base. These two parts fit together well and the 10mm bolts provide a good clamping force.

The downside of this simple arrangement is that neither the head or column tilt and so all machining is square on, unless you buy an angle plate or vice that can be set at an angle – this latter option is a far better option than a tilting column that by nature is not very stiff.

For some of the basic specifications:

  • Drilling Capacity: 20mm
  • End Milling Capacity: 16mm
  • Face Milling Capacity: 50mm
  • Tapping Capacity: 12mm
  • Spindle Stroke: 70mm
  • Throat: 190mm
  • Spindle Taper: MT3 (this one) – you can have R8
  • Spindle to Table Distance: 345mm (MT3)
  • Spindle Speed (Variable): 100-2000 rpm ± 10%
  • Motor Type: DC Brushless
  • Motor Output: 750w
  • Table:
    • Cross Travel: 180mm
    • Longitudinal Travel: 395mm
    • Size: 520x100mm
    • Effective size: 595x140mm
    • T-Slot Size: 12mm (M10 T-Nuts)

To get a better comparison of the Mini Mill and the Sieg SX2.7, here they are side by side:

The Sieg SX2.7 (red) feels like it is 1.5x to 2x the weight of the Mini Mill – albeit a heavily modified Mini Mill (white).

The leadscrews on the Sieg are both 16mmx2mm along with dials very clearly marked at 2mm per rotation.

The Mini Mill leadscrews are 1.5mm pitch with dials that are marked 0.75mm per rotation – you can get a set of corrected dials     to make life much easier with the Mini-Mill and I would advise doing that straightaway.

The leadscrews are well protected with bellows between the column and the table and sliding plastic cover-plates between the     dial and the table.

As you can see in this image and others the slides are much larger and wider than those on the mini-mill. This adds  significantly to the overall stiffness of the machine and reduces any play.

The machine arrived from Arceuro trade with an MT3 drill chuck and a small set of tools.

The tools are much better quality than what I got with the mini mill some 8 years ago.

I chose MT3 as I have a lot of tooling already and so allows me to keep the cost down a bit.

I immediately removed the chuck and fitted an ER25 collet chuck as this is the mainstay for me with a milling machine.

The easiest way of removing the taper is to lock the quill (see later image in this article) and then release the captive allen key bolt on the top of the spindle as this will then force the taper out of the spindle.

The table on the Sieg SX2.7 is 30mm wider than the Mini Mill it replaces and the overall length on this standard model allows me to easily have a Soba vice at one end as a permanent fixture and still have enough room for me to fix a rotary table or to just clamp items directly down to the table.

Initial impressions: well, after setting it up I decided to complete the T-nuts for the rotary table.

The speed control is superb, with a push button increase and decrease. If you stop the machine it will remember the speed when you then hit the start button and gradually comes up to the required rpm.

Being able to see the set speed in rpm is nice.

The Quill lock was not obvious to me at first and was pointed out to me on the Model Engineering Forum.

The lock is on the left hand side of the head as you’re looking at it. A label says UnlockLock and is stuck around a caphead bolt head.

You need to lock the quill between adjustments when milling and when you want to unlock the taper against the captive bolt on the top of the spindle.

The carriageways lock very easily and the fine feed works well, although I need to get used to it as it can be a tad jerky and not as fine as I had hoped. I will see how I get on using the main head feed instead of the fine feed.

The machine is a real step up from the old milling machine – what I believe people call a mini-mill or X2.

Even on the first day the stiffness improvements to the column and width of the carriageways shines through.

SIEG CNC Machine and Metalworking Machine