Gear rack quality classes: available from class 4 to 10

In this video focus on the quality classes of rack and pinions. These are commonly available from quality class 4 to 10, with quality class 4 being the most accurate. In this video, Eric Megens explains what the quality class refers to and, more importantly, what it does not refer to.

Gear rack quality class: total pitch deviation

Grade 4 is the most accurate with a total pitch deviation of less than 20 than micrometers per meter. This means that if a 1-meter rack heats up by 1.5 degrees it will cause a pitch deviation of less than 20 micrometers.

At the same time, the quality of a rack says nothing about its post-treatment, hardness and therefore its feed force. A rack in grade 10 can deliver more than twice the feed force than a more accurate rack in grade 8. This also makes it more difficult to compare rack suppliers because quality refers only to the total pitch deviation. And this is then also often named at 300 or 500 mm.

Apex Dynamics has all the specifications and also has them freely available through our website. Visit the page for straight or slanted rack and download the catalog.