I haven't ever been all that concerned about exact measurements on rakers; some saws or some conditions will allow the user more leeway than others, plus I wonder if playing with increments of less than .005 is worth the time to measure. I usually like a tall raker on dry wood or frozen wood.
I have used an old McC raker guage (kind of like two Oregon ones put together) for years. It also has a bunch of slots for checking angles...a pretty useful tool, but anyway, it has two settings....025 and .030. For any of my current saws over about cu.in., I've never noticed enough difference in green wood between .025 and .030 to matter. For that matter, even rakers that are getting down to maybe .020 still do allright.
One of the things that has always made me wonder about checking rakers is that to be truly accurate, wouldn't one need to measure the raker's drop at the same radius as the bar plus the height of the cutter? Otherwise, you're only measuring the difference between two cords of that same circle. Of course, I suppose many will say that the arc of the bar isn't enough to matter...
I fired up one of my old Homie gear drives a week ago just to see if I could do any better than Babcock's old Dave Brad, and checked the rakers on that saws' 1/2" chain...we're talking .050! We're also talking about 23 seconds to "blast through" a 15" oak stem, about 1/2 frozen. Sorry, no pine right now.
