Grinding aluminum without the grit

At the risk of summoning the ire of Dr. Jeffrey Badger, the legendary Grinding Doc, I bring you some handy little insights from our humble little shop’s surface grinding exploits. Today I’m going to focus on two simple and interesting topics: wheel compound and grinding on non-ferrous metals, specifically aluminum.

Compounding Questions Can Easily Be Solved

Surface grinding is mostly governed by the laws of wear. As I was taught, the laws of wear govern two interacting surfaces, one being necessarily harder than the other. In the world of surface grinding, the wheel (cutter) is harder than the workpiece, otherwise the workpiece would just invariably consume the wheel. Just as it is with milling, drilling or turning, the cutter must be harder than the material being cut to be effective.

In a sort of subset of these rules, I was also taught that the harder the workpiece material, the softer the compound of wheel should be. For example, if you are grinding on soft 1018 machine steel, you should choose the hardest compound of wheel that you have. Conversely, if you are making sparks on something hard, such as when modifying a tool steel cutter, you’ll want to mount a standard white aluminum oxide wheel. Of course, make sure your wheel passes the ring test, is properly mounted, balanced, and is dressed sharp and clean.

Coolant is a must, be it from a misting nozzle, minimum quantity lubrication or flood coolant. No Iron? No Problem! In my formative years I worked for a tool and die shop that made thermoform molds and the corresponding dies to punch the final product from the stock material.

As I moved up the ranks, I found myself spending a few shifts in the grinding and finishing room, putting the finishing touches on the exact molds I’d made a few days prior. Here’s a twist I faced with two pieces of a mold made of 6061-series aluminum! Hardly magnetic. I needed to find a way to hold the mold on the shop’s magnetic chuck.