It is especially important to clean and maintain precision measuring tools such as calipers and micrometers. These tools must be as accurate as possible when using them for measuring sophisticated parts in an engineering or manufacturing environment. By maintaining them and calibrating them often, you can assure that your parts will come out right and that you do not waste any raw material, which would result in more cost per part.
Keep calipers and micrometers in their cases when not in use. In a manufacturing environment, things are often fast moving and calipers and micrometers left on a bench can be bumped and covered by heavy parts. Dropping a caliper or micrometer can damage it as they are very delicate measuring tools that must be kept safe from shocks.
Keep calipers and micrometers clean using soap and water or acetone to remove debris. If dust or debris builds up on a caliper's slide, the measurements may be off. It is also essential that the micrometer measuring stick move smoothly and freely for accurate measurements. Clean each when you see dirt and make sure to blow them off with compressed air after using to remove any wood or metal chips.
Calibrate calipers using precision gauge blocks. These blocks come in sets and are precision ground to be accurate within .00001 inch. You should measure along the full range of the caliper to assure accuracy. If it is a six-inch model, check every inch to make sure that it measures accurately along the entire range of possible measurements. Set the zero and hold up to the light to check for gaps. If one is present, clean the face of the blades and check once again.
Use the precision measure rods included with your micrometers. Each micrometer comes with its corresponding measuring rod. It measures at the largest spot in its range. For a 1-inch to 2-inch micrometer, the measuring rod would be ground to precisely 2 inches.
Keep your micrometers and calipers locked in your toolbox when you are away from work. These items are very expensive and must be kept safe from others unless they are group tools. Place the tools in their respective case and place in a clean, lockable drawer in your toolbox. If you have issues with your measuring tools, there are shops that can professionally calibrate them or you can have your quality assurance department calibrate them. Make sure you mark the date of last calibration so that you know when it was done last.