Sieg X1 mini mill belt drive conversion kit

Precision belt drive conversion kit for X1 model mini milling machines. Designed to replace the original gear drive system for quieter operation, reduced vibration, and higher usable spindle speeds. Custom-built and shipped worldwide.

Overview

This precision belt drive conversion kit is designed for X1 model mini milling machines. It replaces the original gear-driven transmission with a smooth and reliable belt drive system, delivering quieter operation, reduced vibration, and improved long-term reliability - without requiring any permanent modifications to the machine.

Each kit is individually manufactured to order, allowing precise quality control and compatibility adjustments for different mini mill variants.

Why Convert to a Belt Drive?

• Significantly quieter operation compared to gear-driven systems.
• Reduced vibration for improved surface finish.
• Lower mechanical wear and reduced maintenance.
• Wider usable spindle speed range.
• Improved reliability under continuous use.

Pre-Order & Payment Information

This product is manufactured upon pre-order.

• No payment is required when placing a pre-order.
• You may cancel your pre-order at any time before shipment.
• Once manufacturing is complete and the package is ready for dispatch, a payment link will be sent.
• For estimated manufacturing lead time, please contact via the contact form.

Key Features

• Precision machined aluminum pulleys.
• Original keyways machined directly into the pulleys.
• Polyurethane V-belt optimized for small pulley diameters.
• Quieter and smoother operation than gear-driven systems.
• Reduced vibration and improved surface finish.
• Integrated spring-loaded locking mechanism for secure belt tensioning.
• Wide sliding mechanism for quick and easy belt changes.
• Quick-release belt cover.
• Lightweight, durable, and clean mechanical design.
• Installation time approximately 20 minutes.
• No permanent modification required.

Technical Note

Due to the geometry of the large pulley used in X1 mini mill belt drive systems, the bore length is approximately twice the bore diameter. This design characteristic limits the achievable runout tolerances during machining.

As a result, minor radial and axial runout of up to approximately 0.1 mm may be present during rotation. This is inherent to the design and does not affect normal operation or performance of the belt drive system.

Speed Range

Low speed is up to 1000 rpm, high speed is up to 2000 rpm, high speed is up to 3000 rpm (approximate values​​).

Belt & Pulley Design Notes

Polyurethane V-belts are used to ensure minimal flex resistance, minimal power loss, and maximum belt life. Cloth-coated or rubber belts are not suitable for small diameter pulleys and are therefore not used in this design.

The spindle pulley is designed without a countersink for the spindle nut, allowing easier machining and straightforward installation. An installation video is available for reference. Click here to view the installation procedure.

Compatibility

• Sieg X1 Mini Mill

Important Measurement Information

(Please Read Before Ordering)

Different manufacturers use slightly different dimensions on X1 type mini mills. Please verify the following measurements before placing a pre-order.

Pulley Bore and Keyway Sizes

• Small pulley: 8 mm bore with 3 mm keyway.
• Large pulley: 20 mm bore with 4 mm keyway.

If your machine uses different shaft diameters or keyway sizes, please provide the correct measurements. Parts can be manufactured accordingly.

If these dimensions do not match and no measurements are provided, the kit will not fit your mill.

Package Contents

• Precision-machined aluminum pulleys (motor and spindle).
• Polyurethane V-belt optimized for small pulley diameters.
• Custom motor mounting plate (matched to your machine if required).
• Integrated belt tensioning and locking components.

• Belt cover.

• Required mounting bolts.

• Assembly instructions.

Electric motor, milling machine, and tools are not included.

Shipping Information

• Worldwide international shipping via DHL, UPS, DPD or Spring.
• Transit time after dispatch: 3–5 business days worldwide.
• Shipping options are visible in the cart before creating a pre-order.
• No registration is required to view shipping options.

If no shipping option appears for your country, please contact via the contact form so it can be added.

Technical Note

This product consists solely of mechanical power transmission components intended to replace gear-driven systems with a belt-driven solution. It does not include electric motors, electronic controls, or complete machine assemblies.

If you have any technical questions or require customization for a specific X1-type mini mill, please feel free to get in touch before ordering.