It would still give the top plate the correct angle if my brain is telling me correctly. Side plate would be different, probably a sharper angle and would still function. May actually make a chain last longer because of the angle.......
I have argued against this point in several threads, so I will try to summarize some of those perspectives here.
- You need to start with the cutter shape that you want, then determine how you are going to achieve that. If you would file your chains with a rectangular file (90* corners), then go ahead and grind with a 90* profile on your wheel. If you file with a round file, then grind with round profiled wheel, and STOP when the wheel reaches the same depth as you would with your file. If you 'square' file with special bevel-edged files (corner angles greater than 90*), then profile your wheel that way. But don't expect to grind differently than you file and expect the same results.
- Grinding the top plate of the cutter with the flat of the wheel does not give you the same hollow grind cutting edge that grinding with a round profile does. You may prefer one or the other, but they are not 'the same', even if the cutter angle (viewed from above) is still 30 degrees (or whatever).
- If you grind or file conventionally with a true 90* edge you will end up with a weak, unsupported top plate at the point/corner, which square ground users refer to as a 'beak'.
- The importance of the side plate edge often gets overlooked (IMO), even though it does a big part of the work, cutting through the wood grain (cross-cutting). Grinding a deeper 'hook' pushes this edge back farther in the cut, delaying it's entry. Several guys will tell you that they like the 'self-feeding' action this creates, but this means that some of the saw's power is being used to pull the cutter deeper into the wood instead of cutting through the fibers. If you ground a deep hook with a square edged wheel, you would push this cutting action back even further.
we need some experiments.
Nothing like good experimental results! Just need them to be objective, and have enough trials to make sure that the results don't apply only to a specific type of wood (or a specific log!).
Seems this is how all OEM chain is sharpened and only a file or small wheel provides a concave tooth.
Round ground OEM chain is shaped round. Take a look at the side plate, or see how an appropriately sized file or dowel rod fits against the ground surface.
Philbert