#28 - Dressing your Bench Grinder wheels

Last week we talked about one of the staples in every shop, the Bench Grinder. This week, we’ll continue that theme and talk about the ‘care & feeding’ of your grinder.

Just for a bit of clarification from last week, my point about using a slow speed grinder (which is what a 1725rpm grinder is called in the industry) is that one needs to be careful when grinding metal and not heat the metal up too much. With a slow speed grinder, it is much easier to keep the grinding heat under control.

Ok, let’s talk about one of the natural problems with any grinder. After some grinding time, the face of the wheel will get ridges, or become tapered and one must “re-face” the wheel to get back to a smooth grinding surface. There are a couple of ways to do this.

Some grinders, the more professional models, usually have an accessory that is used to re-face the wheels. It bolts on in place of the tool rest and uses a diamond-tipped tool to re-face the wheel. Having one of these makes the task much easier. Unfortunately, not all grinders offer that. If your grinder isn’t that sophisticated, just buy the diamond-tipped tool and use it free-hand. The technique is not that hard to learn, in fact, if you have had enough grinding experience to get your wheel out of shape, you certainly have enough experience to re-face it.

So, let’s say that you don’t have the re-facing accessory and you must do it free-hand. The diamond-tipped facing tool I am most familiar with has a round shank, so that is what I will speak to. The technique is to place the tool on the tool rest as if you were trying to grind the diamond off of the end. Support it very well with your hands. In fact the tighter you hold it, and control it, the straighter your face finish will be.

Make sure you have your safety glasses on, and turn the grinder on. Put the tool on the tool rest. You would let the diamond tip touch the face of the wheel very lightly- you do not want to ‘deep grind’ this- and move the tool side to side as straight, and smooth, as possible. Keep the tool at 90degrees to the face of the wheel and realize that the high points of the wheel face will require a lot of material removal before you will get close to having a straight wheel face again. With patience and a bit of time, you will again have a smooth wheel face to use.