10-02-2013, 04:44 PM
Correction, this is what happens when I post at midnight! Thanks to Patdaly for catching so fast!
We can hold +/-.001 on all surfaces and +/-.0001 on some areas. So the 5X is correct. +.000/-.001 is not sloppy by today's tolerances. Most drawings for "milspec Parts use this and allow for up to +/-.005 or more on most surfaces on AR parts. Getting .0001 (ten thousandth's) tolerances requires Temp controlled room, Heat pressed tooling, reamers, roller burnishers, grinding, hard turning after heat treat, etc. For example. I measures a bunch of AA bolts. The depth of bolt face measured from .1355 to .1365 rounding to nearest .0005. That is one thousandth's tolerance. Headspace is measured in .008 difference in go and no go on most gauges.
Mark Hostetter
Precision Firearms
We can hold +/-.001 on all surfaces and +/-.0001 on some areas. So the 5X is correct. +.000/-.001 is not sloppy by today's tolerances. Most drawings for "milspec Parts use this and allow for up to +/-.005 or more on most surfaces on AR parts. Getting .0001 (ten thousandth's) tolerances requires Temp controlled room, Heat pressed tooling, reamers, roller burnishers, grinding, hard turning after heat treat, etc. For example. I measures a bunch of AA bolts. The depth of bolt face measured from .1355 to .1365 rounding to nearest .0005. That is one thousandth's tolerance. Headspace is measured in .008 difference in go and no go on most gauges.
Mark Hostetter
Precision Firearms
"Precision - The Pinnacle of Perfection."