When building or servicing engines and other machinery, gaps and tolerances must be accurately measured. Your measurements can be spot on thanks to the range of feeler gauges from ToolPRO. If you need to measure finer tolerances, or easily obtain a measurement in fractions of an inch, the ToolPRO master feeler gauge is the tool for you. This feeler gauge measures right down to 0.38mm great for tuning up older distributors. Taking a measurement using a feeler gauge is easy. First, ensure that the gap to be measured is free of dirt or greasy build up. Make sure that the feeler gauges are clean and well-oiled also. Start by finding the closest possible blade that will fit in the gap. If the blade moves too freely within the gap, stack multiple blades until a snug fit is obtained. Feeling for resistance is key here. The proper resistance can be likened to pulling a sheet of paper from under a magazine, or peeling packing tape off a roll. Now, add up the total thickness of all blades used and check this against a workshop manual to determine if your part is within specification.