Kellenberger 1000U Spindle Repair

The Kellenberger 1000U is a cylindrical universal grinder equipped with a belt-driven, grease-lubricated spindle that operates at 1,500/1,700/2,100 rpm. This machine is a highly capable precision grinder known as a workhorse throughout the machining industry. Read the following case study to learn how we solved this customer’s spindle repair challenge.

Northland Tool owns and operates three Kellenberger 1000U machines, giving us micron-level grinding capabilities.

CHALLENGE

When disassembling the spindle, our service technician noted that all exterior and interior cavities were heavily contaminated with coolant. In both the workhead spindle and its drive pulley, the bearings were also heavily contaminated. Bearings on the idler shaft were over-lubricated with blue marine grease, which is not recommended for this application. The DC drive motor bearings were very noisy when rotated by hand, and the motor shaft had radial play. The larger motor bearing was full of sludge and the smaller bearing failed from complete loss of lubrication. The magnetic motor housing had cracks in a through hole in one of the stator plates, which rendered the DC drive motor unserviceable.

SOLUTION

The following actions were performed for this Kellenberger 1000U spindle repair:

Replace all bearings (OEM spindle, pulley, and idler shaft)

Replace all seals, o-rings, gasket, belts, and assembly screws

Recommended replacement of DC drive motor. Customer opted to source and install themselves

RESULT

After adjusting bearing preload, reassembly of all components, and undergoing break-in and testing procedures, this spindle passed our final quality inspection before being returned to our customer with a 1-year warranty.