KRTW1535A: 6″ X 14″ Permanent Magnetic Chuck Oil Proof For Surface Grinder & EDM by | Jul 4, 20266” X 14” 35 KRTW1535A RMWH-1535B. Permanent Magnetic Chuck Oil Proof For Surface Grinder & EDM. Low profile & strong rare-earth magnet. Thin & light weight work piece are ideally suitable because of fine-pitched magnetic poles.