Some Grinder Specific Comments
Infinity (old style Harbor Freight) (Post#134 )
'Side pivot'; Re-positionable lever clamp; rated 80 Watts/4,800 RPM
I like this one the most of this group. It is the simplest design with the fewest number of moving parts. The re-positionable lever is easy to use, and holds the cutters pretty secure. It allowed the best visibility of the grinding operation. The chain pawl is pretty light, and might need to be shimmed a bit more to stabilize it. I could see maybe keeping this one as a 'field' grinder, possibly run off a vehicle inverter.
Harbor Freight (Post #8)
'Side pivot'; bicycle brake vise clamp; rated 90 Watts/4,200 RPM
Despite working on the clamping lever, cable, and vise, it is still sloppy to use. I had to check each time to make sure that the cutter and clamp seated correctly. As another user noted, it also affects your hand position when you have to operate the brake as well as lower the motor/wheel. It was fast to lock/unlock. Also, as noted before, the handle interferes with the visibility of the grinding operation.
Worksite (Post #118)
'Front pivot'; Threaded knob vise clamp; rated 130 Watts/3,000 RPM
I found this grinder the most awkward to use. This might be because it is so much different from others I have used, and I might change my mind as I get more accustomed to it. It has the most powerful motor of the three. It might be OK for a patient user.
Each cutter has to be locked in place, and released, with 2 - 3 turns of a threaded knob. The chain is supposed to be pulled backwards, against the pawl and the direction of the cutters, which is counter-intuitive. Even then, the chain did not slide smoothly through the vise. I may try to disassemble the vise and smooth/bevel the edges of the clamping plates to see if that makes a difference. The knob to lock/unlock the vise rotation is recessed under the base and hard to reach.
I found this grinder difficult to set up because the cutter is obscured as the head is lowered, and the adjustments are not very precise. Accurate depth control is the most difficult. Not only was it hard to see the cutters when setting them up and while grinding, but it was hard to inspect them afterwards, to see if they were ground correctly. Especially the Right side cutters. I used a dental mirror to help, but it still was difficult to tell if I got an accurate or complete grind.
I will try these again with some larger pitch chains, and possibly, with some additional tweaking.
Philbert