Grinding the Cutters

Before I jump into the grinding, I wanted to let you know that a couple of hard to get tools are now available. I have some Galbert Calipers in stock. I have a great machinist but he is only making me 50 parts at a time, so these are only available intermittently. Also, Caleb James has some of this brilliant metal Cigar shaves available. Be sure to click “metal’ when ordering. His Cigar shave is a game changer and I’m thrilled he finally got it into production again.

It’s time to get to the meaty part of grinding drill bits, creating the cutting edges and relief angle. I know many out there are already thinking this process is beyond them. I hope you will bear with me. I gravitate towards processes that might take a little effort to understand, but the practice is very simple. Once you’ve made one bit, even a rather rough one, you have broken the barrier and soon you have a lifetime of great cutting bits, not to mention the fun of resurrecting all your dull discarded bits into being weapons.

In this video, I’m showing how to establish the cutting edge and then freehand grind the area behind the cutting edge so it has a very slight relief angle (is a bit lower than the cutting edge). In the next post, I’ll show how to test the results and make subtle alterations to the grind if you don’t nail it the first time. I think evaluating the cutting action and returning to the wheel for adjustments is when you will have the “A-ha” moment. If the cutting edge is to high in relation to the area behind it, the bit will cut too aggressively. If it’s too low in relation to the area behind it, it will cut too slowly or not at all. In later posts, I’ll show a way to set up this operation so it’s basically automatic, but I think seeing it freehand first is helpful to focus on the process and results. You might be surprised at how effective you can be doing this freehand. A drill bit doesn’t have to be perfect looking to work perfectly.