This is general used with the Cylindrical Grinding Attachment. Of course, It can be used for grinding internal taper.

Capacity:

Internal spindle...........................................20,000rpm

Length of hole up to...................................1-9/16" or 3" (40mm or 75mm)

Range of bore to be ground......................5/16"- 3/4" (8-20mm)

                                                                   or  1/2"-2" (12-50mm)