Small eccentric pin grinding gets easier

American Machinist, January 2000

Toyoda's GT-011 eccentric pin grinder provides continuous grinding of different phase pins with C and X-axis synchronized control.

The GT-011 is a flexible, compact eccentric pin grinder designed for manufacturing small compressor shafts. First introduced at the Toyoda Machinery Technical Fair in Japan late last year, it is now available to the U.S. market.

"The traditional approach to grinding shafts with cylindrical pins requires multiple machines and setups," states Jim Kletzien, national sales manager of

Toyoda Machinery USA. "Each machine would have a chuck positioned to accommodate the placement of a particular pin in relation to the centerline of the part. The chuck creates a new centerline based on one set of geometry, while the next machine would do the same for a pin having a different location."
"The GT-011 eliminates the need for multiple machines by coordinating the wheelhead movement with numerous, varying centerlines while the chuck maintains a single centerline through the part. This lets the wheel chase each pin as it spins off-center from the shaft, resulting in a round pin, ground off-center," says Kletzien.

According to Toyoda, twin rotary grinding with one chucking ensures dimensional accuracy and reduces changeover time by more than 90%. Only one program change is required for adjusting the eccentric in the the C and X axes.

The grinder is capable of grinding diameters from 0.196 to 1.181 in. (5 to 30 mm) and up to a maximum length of 9.843 in. (250 mm). Due to the linear motor feed and hydrostatic slideway, the wheelhead feed mechanism is backlash and friction free. And because small shafts are ground at a high rpm and require a very fast response, the linear motor lets the grinder follow the eccentric profile and achieve roundness accuracies of 2

Among the many optional accessories for the GT-011 grinder is a semiautomatic load/unload unit.

TOYODA - Toyoda Machinery USA-Machining, Cutting Machines Division, 316 W. University Drive, Arlington Heights, IL 60004. Tel: 847-253-0340; Fax: 847-253-0540.