Bench grinder adapter for grinding/sharpening HHS lathe tools

**hemmjo** · Aug 1, 2023, 06:44 PM

This is how I made an adapter to grind consistent relief angles on my lathe tools. I included some general dimensions since your needs may be similar, but will not be the same. I just made these parts from items I had in my “will need it someday” box.

For a long time I have been grinding HHS lathe tools freehand. Getting older now I need a better way to make and to sharpen good tools. MY little 6” Delta does a good job on small tools. The tool rests were never adequate.They are just small die case aluminum pieces (fig 1). I upgraded the tool rest several years ago with a piece of angle iron and two clamps made from angle iron(Figs 2,3,4). This stiffened up the tool rests a lot and kept the soft aluminum from wearing away.

Click Images to enlarge

Bench grinder adapter for grinding/sharpening HHS lathe tools-1-4-hmt-grinder-adapter.png

Using the upgraded tool rest as the starting point, I made an adapter that can be set to desired angles. The adapter consists of 3 parts; an old 3” door hinge, a piece of 14 gauge steel plate 4” square and a piece of 1/4” x 2” x 4” cut from piece of rusty angle (fig5). The parts were drilled and tapped to make use of the existing holes in the hinges. One hole on one side of the hinge was cut to create a slot. The 1/4” base plate is attached to the hinge with a single flat head machine screw the was filed to be flush with the surface to the hinge (fig 6) The top plate is held to the hinge with 2 button head machine screws (fig 7). Longer socket head machine screws thread though the base, press on the tool rest to elevate the adapter (also fig 7)

Bench grinder adapter for grinding/sharpening HHS lathe tools-5-7-hmt-grinder-adapter.png

A side view of the assembled adapter is shown (fig 8). The adapter mounts on the upgraded tool rest (fig 9). The adapter attaches to the tool rest with a 1/4” hex bolt (Fig 10). This figure also shows a low angle on the adapter. A high angle is shown in figure 11.

Bench grinder adapter for grinding/sharpening HHS lathe tools-8-11-hmt-grinder-adapter.png

The adapter is easily changed from the course wheel on the left to the finer wheel on the right while maintaining the same angle. So you can grind the rough shape then switch wheels to finish and to sharpen(figs 12-13).