What is the type or grade recommended use for in house calibration? As far as a gauge block set.
That depends. If you are calibrating calipers and micrometers then Grade 2 is adequate.
However, to have proper calibration you also need to have procedure, training, and measurement uncertainty calculations. Additionally, have the gage blocks calibrated by an accredited lab.
One other point, if you are using them for internal cal, I suggest an annual cycle for the block calibration.
Hope this helps.