In this video attention is paid to the quality classes of racks. 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 what should not be
Rack and pinion quality class: total pitch deviation
Quality class 4 is the most accurate with a total pitch deviation of less than 20 micrometers per meter. This means that if a 1 meter rack heats up by 1.5 degrees this will cause a pitch deviation of less than 20 micrometers.
At the same time, the quality of a rack says nothing about the after-treatment, the hardness and therefore the feed force. A rack in quality 10 can deliver more than twice the feed force than a more accurate rack in quality class 8. This also makes it more difficult to compare suppliers of racks because quality only refers to the total pitch deviation. And this is then also often stated at 300 or 500 mm.
Apex Dynamics has all the specifications and has them freely available on our website. Visit the page for straight or oblique rack and pinion and download the catalog. Or watch the video here…