Precision Grinding a Hardened Shaft with an Improvised Toolpost Grinder

[Crusty]

I needed to resize a piece of hardened shaft for a fixture I'm making so I made a mount for my angle grinder to use it as a toolpost grinder on my lathe. I started with a good sized chunk of 6061 and hogged out the middle to fit my grinder then drilled it to bolt onto the top of my lathe toolpost. I've got a ¾" roughing end mill that's worth its weight in gold and the mill area looked like an aluminum blizzard had just hit when I finished. The mount is nice and rigid when mounted.

Since you can't reverse the grinder rotation the lathe needs to turn in the reverse direction so the surfaces meet in opposing directions. The lathe ways are shielded with some old jeans (wetted with water so they don't catch fire) and the grinding goes slow, never more than .020" off the diameter and feeding very slow, and you reach your target the same way you catch a unique rabbit - unique up on it ☺. The finished part doesn't have a $1000 ground finish because I used the wheel that came with my Hitachi grinder but it is dimensionally accurate and all it cost was the chunk of aluminum.

In action

From the backside