Bühler 1.57" x 7.09" x 7.87" 2-High / 4-High Combination Rolling Mill - IRM Factory Refurbished

Description

Bühler 1.57" x 7.09" x 7.87" 2-High / 4-High Combination Rolling Mill - IRM Factory Refurbished for Precious Metal Coinage

Manufactured by Bühler Maschinenfabrik of Pforzheim, Germany, this precision combination rolling mill is a compact, rigid-frame system offering both 2-high and 4-high configurations in a single unit. Built in the heart of Germany's historic precious metals district, Bühler mills of this class were engineered specifically for rolling gold, silver, and platinum group alloys, making this machine a natural fit for minting and coinage applications.

The mill is configured for the production of silver coin strip, where gauge consistency and surface quality directly determine blank weight tolerance and final strike quality. In 4-high configuration, the Ø40 mm (1.57") work rolls supported by Ø180 mm (7.09") backup rolls deliver the high specific rolling pressure and minimal roll deflection needed to hold tight gauge tolerances. Converted to 2-high, the mill handles breakdown passes on cast silver bar or heavier strip. A dual handwheel screwdown with central adjustment provides synchronized or independent side-to-side roll gap control for precise crown and parallelism management.

IRM Factory Refurbishment
This package restores the mill to factory-level performance standards through a comprehensive mechanical and electrical overhaul. IRM will fully disassemble, clean, and repaint the mill, followed by a detailed inspection of all components to ensure compliance with factory specifications. Any components found to be out of specification will be repaired or replaced as required. The rolls will be reconditioned to factory specification, including precision grinding, industrial hard chrome plating, and a final satin finish, with roll faces and journals restored to ≤ 0.0001" TIR concentricity. The rolls will then be reinstalled and all adjustment settings verified for proper alignment and operation.

IRM will also install machine guarding to protect moving parts and nip points to the fullest extent consistent with operational access, ensuring both safety and usability for the customer's application.

The mill will receive a complete electrical refit built around a new 480V, 3-phase control system. A new variable frequency drive provides infinitely variable speed control with dynamic braking for controlled deceleration and emergency stopping. The control system includes a safety relay, line reactor, control transformer, 24VDC power supply, and fusing, with all components mounted in a NEMA 4 main enclosure with a through-door disconnect. Spare control I/O, safety circuit capacity, and terminal connections are included for future integration of customer auxiliary equipment.

A separate, centrally located operator station provides all mill functions, including Mill Start, Mill Stop, Forward/Reverse selection, Emergency Stop, and variable speed control.

This mill includes a 1-year full warranty and will be fully assembled and operated on IRM's floor prior to shipment, with final acceptance testing demonstrating full functionality of all mill systems and controls.

Included with the Mill
Two (2) Spare Sets of Work Rolls
Two Binders of Original Bühler OEM Documentation

Note: Images are simulated representations of the refurbished machine. Actual appearance may vary upon completion.