In article , Phil Teague wrote:
(Ken Strauss) wrote in message om...
Many small lathes quote impressive but incomplete accuracy numbers in
their specs. For example, the Prazi SD400 (see
http://www.emachinetool.com/new/cata...?ProductID=180)
claims a "spindle accuracy of 0.0002". What would be a reasonable
expectation of total accuracy? Say the variation in diameter along 12"
between centres?

I don't think .0002" is necessarily exceptional for spindle runout. My
Chinese 12 x 36 is at least that good. The question of variation in

as is my 4015 3n1. well, close, i could only guess, it was less than
1/2 a thou. what impressed me was the the perimeter of the chuck wasn't
much worse. now, i cannot actually remember the 3 jaw accuracy, but it
was better than i expected, certainly better than the rigidity expected
from the lathe. but that is moot, right? i did not have any really
"round" stock for testing the chuck.

12" between centers would probably depend more on how well your
tailstock center is aligned with your headstock and how accurate your
centers are. You should be able to turn something between centers to
the accuracy of your spindle TIR which in the case of the Prazi should
be .0002".

what, steel? rigidity seems to be the limit on my Grizzly 4015, which
weights 380lbs or so. the lathe base is approx the same size as the 9x20
chinese imports. that Prazi does look nice, pricey little devil. --Loren