Centric clamping gerared scroll chucks DURO-M in steel design

The Duro-M ROHM is a manually operated scroll chuck with through-hole, designed primarily for clamping turned parts on manual turning machines, but also suitable for horizontal and vertical turning machines, milling machines, rotary tables and dividing attachments. Its chuck body is made entirely of steel, optimized both for accessibility and for reduced weight and mass inertia.

Characteristic scallops machined into the base body reduce overall weight, which not only protects the spindle bearings but also allows for greater acceleration and lower energy consumption. The scalloped end face further enhances tool access by removing any unnecessary material that could obstruct operations.

The single-part base body, crafted from one piece of steel, offers extremely high rigidity—essential for precision—while minimizing visible screws and preventing chip accumulation. Around the circumference, a drip edge is incorporated to ensure controlled coolant drainage directly off the chuck body’s edge.

In terms of force transmission, the Duro-M outperforms all other scroll chucks. It achieves one of the highest maximum clamping forces with comparatively lower input forces and responds very sensitively to adjustments, allowing for precise control of clamping pressure. Its superior force transmission also enables a lower-profile design, which increases the working envelope, reduces material usage, and further cuts weight—translating into energy savings and the potential for higher spindle speeds.

Every Duro-M is equipped at the factory with a zero drive, the most precise of the multiple drives on the chuck. This drive is marked with an arrow and is used when grinding jaws to maintain exceptional concentricity or when measuring the machine/clamping system’s concentricity, as detailed in the operating instructions.

The clamping mechanism consists of four clamping jaws that move radially via a scroll ring with spiral-shaped guideways. These jaws engage the guideways on the scroll ring and clamp axially onto the workpiece when the ring is rotated by one of several toothed drives. Adjustment is made by inserting the clamping key into the head of a selected drive and turning; each drive is then secured with a retaining screw. The entire mechanism—drive, scroll ring, and cover—is housed within the one-piece chuck body, resulting in a compact, rigid assembly sealed at the rear by a screw-mounted cover.