The grinder tool posts are used to hold the 8900 high-speed grinder on your lathe for polishing, or fine grinding jobs. The 8987 riser grinder tool post when the lathe riser blocks are in place. You can also use the 8976 grinder tool post to hold the grinder body on center with your lathe.

Image shows the 8976 grinder tool post in place holding the 8900 High-Speed Air Grinder (P/N 8900 sold separately.)

About the high speed air spindle…

In most machining conditions it is not necessary to achieve tool speeds faster than the 10,000 RPM that can be produced with the standard DC motor spindle with optional P/N 4335 high-speed pulley set. However, for engraving and other applications where extremely small, pointed tools are used, higher speeds are required for good finishes and acceptable feed rates. The 8900 spindle is capable of speeds up to 54,000 RPM and will hold 1/8″ diameter cutting tools in its collet spindle. Three carbide tools with various cutter face angles are provided with your engraving head along with 7 grinding tips.

The high-speed spindle fits into the hole in the toolpost and a screw is tightened laterally to secure it in place. Do not overtighten this or the hold-down screw that secures the toolpost to the table. The grinder can be used for putting a fine finish on hard parts, but it does not have the high torque needed to remove larger quantities of metal.

See more on the P/N 8900 high-speed grinder for more details on its use.

Precaution:
A carbide tool is being rotated at extremely high speeds. Should it shatter, pieces are flung outward at high speed. While eye protection is always recommended for any machining operation, good eye protection is absolutely imperative when using high-speed tools like this.