Announcement

Collapse
No announcement yet.

Slip gauges

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Slip gauges

    What is the difference between workshop grade and inspection grade slip gauges? I had a search on Google with no luck . Would it be that one is slightly more precise than the other, but for general use would it really matter ? David

  • #2
    For around the home shop it does not matter.

    About all I know is inpection grades are better than .000050" I would guess shop grade ones are +/- .0001

    Comment


    • #3
      Inspection grade blocks will be held to a narrower tolerance range. Check the catalog or manufacturers site to get exact numbers.
      For general use in a home shop, workshop grade is typically just fine - it depends on what your needs are. I suspect that they will be plenty accurate for your purposes.
      Keep in mind that when you stack up a bunch of blocks, you are compounding the inaccuracies.
      Location: North Central Texas

      Comment


      • #4
        Thanks for your replies, I have been told thet slip gauges need recalibrating on a regular basis, would this be needed for the likes of me who would only use them very little ? Can't really see how they could alter. David

        Comment


        • #5
          Originally posted by David S Newman
          Thanks for your replies, I have been told thet slip gauges need recalibrating on a regular basis, would this be needed for the likes of me who would only use them very little ? Can't really see how they could alter. David
          Steel gages will change over time but with the changes being in the millionths of an inch range. Current production gages cryogenically treated will change only slowly. If you're using the gages mostly for micrometer calibration and occasional the sine bar setup there's no real need to worry.

          As for the gage errors, here's a chart from Starrett listing the error ranges: http://catalog.starrett.com/catalog/.../4400/4328.pdf If you look at the lowest grade (old "3" or "A") the errors are pretty small and are centered around the proper length, so there should be little "stacking" of errors with a set that was put together fairly well. The worst error of 4 gages in the .400-.999" range would be +- .000048" but would have a good probability of being more like +- .000012" (don't make me break out the statistics, it'll give both of us a headache). Note that that's from the "shop" grade gages, "inspection" grade would be better and "lab" grade would be fantastic.

          I spoke for a time with the manager of the Sandia Laboratories Physical Standards shop. I don't think that they messed with anything as imprecise as the lab grade standards. I saw a topographical map of a 16x30 surface plate that have millionth graduations. Impressive, but what was *really* impressive was that the surface plate was 16' x 30' and 4' thick - feet and not inches.

          For most of us in the home shop as long as the gages can be wrung together they're probably as good as we can expect to need.

          Comment

          Working...
          X