Do All Electric Chain Sharpeners Rotate in the "Wrong" Direction?

After more than a year, I just noticed that the grinding wheel on my Harbor Freight sharpener appears to rotate in the "wrong" direction. When sharpening by hand, you are instructed to push the file away from the cutting edge, not pull it toward the cutting edge. My HF rotates such that the grinding wheel is spinning toward the cutting edge.

Has anyone else noticed in which direction theirs rotates? If so, which direction and brand?

When grinding it doesn't really matter and actually "reverse" rotation is beneficial since it will not leave a burr on the outside of the cutter. The outside of the cutters are "chromed" and that coating is actually harder than a file. So by pushing the file from the inside out, you are chipping the coating off the tooth. Reversing direction will ruin the file, very quickly if not instantly.

But Stihl's instructions for sharpening by hand specifically say to sharpen from the inside out, don't they?

Also, I noticed this morning that my HF sharpener only rotates in the "wrong" direction when sharpening half the teeth. When you rotate the holder to do the other teeth, the wheel rotates from the inside out. Could this be causing my saw to cut in an arc, rather than straight through a log, since the teeth are being sharpened differently?

I'd still like to know how other sharpener's work. Is this only the HF model that does this?

Yup, Chipping the coating is what you want to happen, as it is really too hard to cut. Reversing the file direction would mean you're attempting to cut the super hard coating while it is supported by the relatively soft steel of the cutter behind it. That ain't happening with a file but a grinder will have no trouble doing just that.

No danger of it creating an arc because of the direction the wheel rotates. Any burr left on the outside of the cutter will almost instantly be removed once the chain hits wood. If your chains cut in an arc after coming off a grinder, I'd check the length of a few cutters on either side of the chain with a caliper to ensure the grinder was removing material evenly, slight adjustment when swinging some grinders to do the opposite side of the chain is sometimes required.

Exactly, & also check raker height from left to right. Either way you can get a "curved cut" because one set of cutters is removing more material than the other. A C