Good buys, Eric. It looks like both of the wheels on your "carbide tool grinder" are for grinding steel, not carbide. Nothing wrong with that, since a lot of owwmer-type grinding is on steel, not carbide.
On the carbide tool grinder, some important things for owwm users of same:
Do not use diamond wheels on steel. They are intended for grinding carbide. And as already mentioned, coolant should be used, except for the very lightest grinding, i.e., just a simple quick touch up of a carbide cutter edge. The amount of dry carbide grinding you can do with a diamond wheel is very limited--generally, the denser the diamond particles are on the wheel, the less the wheel will tolerate dry grinding. Grinding tempered or HSS steel on a diamond wheel will will tend to tear the expensive diamond particles off the wheel in short order, regardless of whether coolant is used. There are more appropriate and less expensive abrasives for steel grinding.
Flange-mount diamond wheels for the 6" type carbide tool grinders vary in price from around $100 each to over $500 each, depending on the diamond quality, density of the diamond particles, and the type of bond or substrate that the diamond abrasive is set in. You get what you pay for with a diamond wheel. The cheaper ones cut neither very quickly nor very well in the long run.
"Green" wheels are intended for grinding carbide, and also for grinding aluminum, brass, copper, or other soft metals, although they do none of the above very well, and will not give the surface or edge quality on carbide that you can get with a diamond wheel, and they do not like grinding steel. Ideally, you'd use a green wheel for rough-grinding a carbide tool (if needed), and finish the edge with a diamond wheel.
Wheels intended for steel or ferrous grinding do not like to grind carbide. Grinding carbide on a wheel intended for ferrous grinding will dull the abrasive in short order, and won't do much to the carbide.
Some owwm examples of the value of a carbide grinder have already been noted, but there are a few others. With the addition of the small miter gage accessory or other custom-made guide/clamping attachments, you can do fairly accurate finish or edge grinding which would be more difficult to do on a standard bench or pedestal grinder. Also, since you have a flat face to grind on, you can get flat surface results if you want same. On a standard grinder you get hollow-ground results grinding on the curved face of the wheel. While you can do somewhat the same type of flat grinding on the side of a standard or recessed grinding wheel, you don't have that nice large table of the carbide tool grinder to work with. The tables of the carbide tool grinder don't easily (or at all) adjust the the angles needed for plane-iron or chisel grinding, as already noted, but if you have a chisel or plane-iron which some ham-handed previous user has ground to something other than a good 90-degree end, you can very quickly and accurately restore the end to square with the use of the miter gage or guide on the carbide tool grinder and then go to your standard grinder to do the 25-ish degree cutting angle and sharpening. This is especially helpful to those of us who c*ll*ct old planes and chisels for users instead of simply for dust c*ll*ct*rs on a shelf. Starting with a perfectly square end also makes free-hand finishing of the cutting angle and edge of a plane iron or chisel easier to do in the long run if you happen to like to use that method.
by: blenzi