Desktop Mini Mill CNC Lead-screw kits  

(See also G-Code programming services) 

Designed for the Sieg X2, but should be suitable for other similar mini mills with different branding e.g. 

Harbor Freight Central Machinery (44911) , Cummins Toolnow (7887) 

Homier Speedway (03947), Chester Conquest , Sealey (Sm2502) ,Grizzly (G8689) 

These, and other mini mills, are said to be the same as the Sieg X2. Whatever your make, please see Basic Checking Dimensions below before purchasing. 

The parts in this kit have been thoroughly tested for many hours on a working conversion. Designed to be easily fitted, with minimum modifications to the machine, with no loss of travel in X, Y or Z. (See Price, Contents, Materials, Design & Fitting details below) 

Basic Mini Mill Checking dimensions (in mm)

  (X) Table (excluding leads-screw supports): 385 long x 92 wide x 31 deep, 220 travel, with 72 hole centres for lead-screw support fixing (M6)

(Y) Saddle: 150 long x 93 wide x 48 deep, 100 travel

(Y) Base: 50 hole centres for lead-screw support fixing (M6)

If these sizes do not exactly match your machine please contact us

Kit Contents 

The self-assembly kit, shown in the pictures below, comes with all the parts required to convert the X, Y and Z-axes to accept NEMA23 stepper motors, and includes: 

• X, Y & Z lead-screws with adjustable anti-backlash nuts
• X, Y & Z lead-screw supports/bearings
• X, Y & Z NEMA 23 stepper motor mounts
• All necessary metric fixing screws/nuts/washers for fitting the kit and your chosen stepper motors
• Fully detailed step-by-step installation manual with pictures and drawings. Supplied in MSWord format. (Printed paper copies available on request, at £9.99 each including P&P)

Kit Materials

• Lead-screws are mild-steel, 14x3 trapezoidal, to ISO 2901/2903 (DIN103). With 6.35mm (1/4”) ‘Dee’ coupling journals.
• Lead-screw/stepper motor mounts are made from black Delrin®, which is an acetyl resin, engineering plastic, often used as a metal substitute, capable of operating in temperatures in excess of 90^oC, and is resistant to petroleum-based substances.
• Each lead-screw is mounted in sealed ball races, with added thrust ball races.
• Anti-backlash nuts are made from white Delrin®, which is a highly effective bearing medium with a low coefficient of friction, extremely wear-resistant, capable of operating in temperatures in excess of 90^oC, and is resistant to petroleum-based substances. Although lubrication improves performance only intermittent lubrication is required. 

Kit Design

• Parts have been designed using state-of-the-art 3D CAD software. The main parts supplied are all CNC machined from solid billets.  
• With tested, sturdy assemblies, that match the torque of the drive motors, the kit is designed to suit the machine, and it's intended uses. However, like the machine, is not really suitable for 24/7 production engineering.  
• NEMA 23 motors (not supplied, up to 3Nm torque, 1.8Nm min recommended) are assumed to have M5 clearance fixing holes. Motor spacers have been sized to suit Lovejoy L050 couplings, giving a 13mm gap between the end of the motor shaft and the end of the lead-screw. Other flexible couplings may be OK, but check compatibility before buying.
• Nuts are adjustable for wear, and when correctly set will give less than 0.05mm backlash (which can be compensated for in Mach3® software etc)

Kit Fitting

• The kit is designed to fit with the minimum modifications, by utilising existing fixing holes etc. However, 3 x M6 holes and 2 x M5 holes need to be drilled and tapped to fit the Z-Axis lead-screw, and a small modification to the saddle is required to fit the X-Axis lead-screw.
• The conversion will disable the manual operation of the milling machine. However, if stepper motors with double shafts are employed then some degree of manual use will be possible. No modifications, required for the kit, will prevent the parts removed from being refitted to re-create the original manual machine, if ever the need should arise.
• For safety reasons we recommend that a suitably qualified person fit the kit.