A particularly aggravating thing about Grizzly is they seem to NEVER provide ANY information about the accuracy of most things they sell. This is especially annoying when it comes to lathe chucks,drill chucks,live centers,etc.. Makes me wonder if they are trying to HIDE this info from the customers.
I guess their customers are just supposed to be too ignorant to think to want info about these things.
I,for one,refuse to buy any such products where tolerances are a consideration. When I buy a chuck,I want to know if the expected runout is .003"(average Asian accuracy),or more(or,hopefully LESS!).
When I have bought lathes with D type spindles,I have sometimes gone over them with a good toolpost grinder,to make them perfect IN SITU,like Hardinge did with their taper nose HLVH's. But,that is not possible with threaded noses. The best you can do is buy chucks with separate back plates,and turn them true and to press fit diameter in the lathe. You could grind the tapered bore. That's about it.