Here's a better way to hold tools securely while you're grinding them—and take the guesswork out of creating the right bevel angle. It's a short piece of 2x4 with an angled end and a 1-1/4-in. hole for a clamp. Make one for chisels and plane blades, and a few more with different angles for wood-turning tools. Large labels with the tool's name tell you which blocks are for which tools.
For a Delta grinder with a 6-in.-diameter wheel, a 5-1/2-in.-long piece of 2x4 aligns the tool to the wheel just right. For other grinders you may need to adjust this length. Note: The angle you cut on the block is not the same as the tool's bevel angle. But let's skip the math. To determine the block angle, turn off the grinder and hold the tool's bevel flush against the wheel. The angle of the tool shaft to the workbench is the angle to cut on the 2x4.