Have you tried to use a feeler gauge and could not get the feel? Using a feeler gauge is not a precise thing, it takes time to get the feel of the gauge.
Many people try to explain the “feel” part of measuring with the feel of paper, but this method does nothing to help you understand. The best method is to use a micrometer.
Using a Micrometer to use a feeler gauge
When you use a micrometer to use your feeler gauge you can do it two ways. One way is to set a known amount on the micrometer. The other way is to set an unknown amount on the micrometer and not look at it.
By setting a known number you can match it to the feeler gauge. This will be your starting point to train you for the correct size feel. Work the feeler gauge around, in, and out of the matching gap until you can recognize the different feelings.
Next up you can work with an unknown size. Set your micrometer without looking at the numbers, then get your gauge set ready. Work your feeler gauges through the unknown gap and stop when you think you have the one. Check if you are anywhere close to the setting. You can continue to try this as a way to test your newfound feel.
Types of feeler gauges
In essence, a feeler gauge is a go, no-go way of measuring. They don’t always have to be the pack of thin shims. Feeler gauges can be large, round, or have more than one size on the measuring face.
Generally, all feeler gauges are marked in both standard and metric. But if you want whole numbers in either standard or metric you need to buy each type. For us, we mainly work with metric measurements.
Feeler gauge sets can be pre-bent, or straight, you cannot bend a straight-set, it will damage the gauge. You can pick up a brass set for measuring magnetic parts. Some gauges have a range of measurements on one blade. When you use this type of gauge it can help you hone your feel. You can feel the top end and the loose side of the gap with the same blade.
Pin gauges are still feeler gauges, they are just round. You can use pin gauges to pass or fail a hole. Use a pin gauge holder with go-no-go sides and fit it with the smallest size on one side. On the no-go side, you can put the larger gauge that will show you the hole is out of tolerance. You still need to practice using a pin-type feeler gauge because the pin has to be positioned perpendicular to go in the hole.
Pin gauges can come in metric and standard, though the metric can be harder to find. With all the different sizes offered do not drop the pin gauges, it would take forever to get them back in order!
Practice makes perfect
Practice with known and unknown gaps. Work on gaps with moving parts, like a points gap in a distributor. By feeling gaps that have spring pressure or pivoting parts attached, it will help you hone your skills. Keep your micrometer handy and give yourself a refresher with it. Remember, practice makes perfect.
When restoring an old Porsche we have many instances to use a feeler gauge. Transmission rebuild, distributor set up, valve clearance, and ring gap, are the stand-out measurements we need to do the job. Don’t forget to check out our other fundamental measuring lessons, and happy training.