jscpm
Titanium
- Joined
- May 4, 2010
- Location
- Cambridge, MA
I often prefer to measure dimensions as a height above a surface plate. For example, if I have a block I will measure its top surface's height above the plate. I don't really trust my vernier height gauge to better than a thousandth or so. So, if I want to measure to say +/- 0.0002" it can get pretty tedious because I make a preliminary measurement using the height gauge, then make a gauge block stack to that height, then check the stack against the work piece, then adjust the stack and repeat the process until I have it within 0.0002" consistently. To do the comparison I use a test indicator mounted on a surface plate stand.
It's especially problematic to do this when I need to measure the height to an overhang. To do this I invert the arm of the height gauge so it touches the underside of the overhang and compare the arm to the gauge block stack. The problem here is that I am not actually comparing the block stack to the overhang, but to the arm, so I am worried about the additional error that introduces.
Does anybody have any suggestions on technique using this equipment (gauge blocks and an ordinary precision vernier height gauge)?
It's especially problematic to do this when I need to measure the height to an overhang. To do this I invert the arm of the height gauge so it touches the underside of the overhang and compare the arm to the gauge block stack. The problem here is that I am not actually comparing the block stack to the overhang, but to the arm, so I am worried about the additional error that introduces.
Does anybody have any suggestions on technique using this equipment (gauge blocks and an ordinary precision vernier height gauge)?