What are feeler gauges made from?

29th February 2020


What are feeler gauges made of?


	Shop for Feeler Gauges


		Feeler gauges are commonly made out of tempered tool steel or stainless steel. Both remain strong even when machined to widths of only a hundredth of a millimetre.

		Tempered tool steel can rust if not looked after correctly. Generally, the tempering process can provide a protective oxide layer which helps to prevent rusting. This layer can be scratched or worn away leaving the blade of the feeler gauge susceptible to rusting. Stainless steel has a greater resistance to rust, but tends to be more expensive, which is a factor to consider when purchasing.

		Rust resistance
		Rust resistance is essential, particularly as feeler gauges are often used in wet or humid conditions. A motor vehicle engine bay is a key example of a location where you may be working in high humidity.

		Feeler gauges must be rust resistant because any corrosion may alter the thickness of the blade and result in incorrect measurements. Once a feeler gauge becomes rusty, the precision of the gauge is compromised and the gauge should be discarded.

		Strength and flexibility
		Metal used to make a feeler gauge must be suitably flexible as they are often applied in awkward and hard to reach places, for example within car engines.

		The metal leaves need to be flexible but also rigid enough so that they are not bent out of shape.

		Why do some feeler gauge sets come with a single brass blade?
		A single brass blade is included in some feeler gauge sets. This is because early models of electronic ignition systems had a requirement that the air gap between the reluctor and the pickup had to be set with a non-ferrous metal (any metal that does not contain iron).

		A brass blade should be used to set a reluctor air gap. If a ferrous metal is used you may magnetize the reluctor and cause it to function incorrectly.

		Plastic casing
		Some cases are made from impact resistant plastic rather than metal. These gauges are more affordable but they are also easier to damage.

		Why do feeler gauges vary considerably in price?
		Feeler gauges vary considerably in both price and quality. Feeler gauges made out of tempered steel tend to cost more. Whereas plastic gauges are more affordable. Price generally corresponds to the durability of the tool and the extent of measurements the tool is able to cover.