OK, I'm gonna' get bawled out for this BUT..... here goes.
I've always kept a few mics and calipers around even before I got my little mill and lathe. But anyways, I finally GOT a lathe and figured I'd better pony up the money and buy at least one good digital mic as a benchmark. So I spent the almost $300.00 for an "entry level" brand name 1" mic that reads to .0001
This is after perusing sites like Lon G'island Indicator and such, reading the "ratings." Turns out the ratings on mic's calipers and indicators are based for the most part on how easy or hard they are to repair.
I also stumbled onto a pawn shop special on a set of good manual mics for about 15 cents on the dollar. So's Ive got a couple reference mics.
And I've got a Grizzly manual mic and some Grizzly calipers.
AND, I bought a really cheap .00005 digital micrometer from a Harbor Freight sale for 20bucks. That's right, 20.00 for a mic that's supposed to be as accurate as a 300-500.00 mic.
and it IS...... side by side it IS just as accurate.
These are all good tools.
My point is that this is OLD TECH...... micrometers have been around for a hunnerd years and they ain't going to get remarkably better or worse.
I don't own the Grizzly micrometer in question so to some my opinion will be worse than useless. Some may even rear up and grunt stuff about "don't give opinions where you don't belong..."
But I would buy it without reservation. I've been happy with Grizzly stuff and where else can you purchase where the owner of the company monitors this shooting board?
hth
al