{"id":203,"date":"2016-06-13T19:48:00","date_gmt":"2016-06-13T19:48:00","guid":{"rendered":"https:\/\/hstspindles.com\/index.php\/2016\/06\/13\/how-to-replace-cnc-spindle-bearing-part-2\/"},"modified":"2023-11-02T19:53:03","modified_gmt":"2023-11-02T19:53:03","slug":"how-to-replace-cnc-spindle-bearing-part-2","status":"publish","type":"post","link":"https:\/\/hstspindles.com\/how-to-replace-cnc-spindle-bearing-part-2\/","title":{"rendered":"How to Replace CNC Spindle Bearing Part 2"},"content":{"rendered":"

PART 2 of\u00a0<\/strong>How to replace damaged bearings on a precision CNC\u00a0spindle<\/strong><\/h2>\n

Angular Contact Bearing Installation and Lubrication<\/strong><\/p>\n

This is the Second in a five part series of tips and suggestions for replacing bearing in a precision CNC spindle.\u00a0 This series is specifically for the DIY person with limited resources. It is not a comprehensive description of how a fully equipped shop<\/a> that specialized in spindle repair works.\u00a0 While we will reference certain specific spindle makes it is primarily intended to be rather generic. If you have a specific question please send an email\u00a0at info@highspeedtechnologies.com<\/a>\u00a0or call 1-603-483-0333.<\/p>\n

Last week we considered some tips on getting your spindle apart. Now we will need to get and install the correct bearings. So this week we\u2019ll speak about Angular Contact Bearings, lubrication and how to preload them. Next week we\u2019ll discuss Cylindrical Roller Bearings.<\/p>\n

Super Precision Spindle Bearings<\/strong><\/p>\n

When we\u2019re speaking about bearings on a CNC spindle we\u2019re speaking about two different types, Angular Contact and Cylindrical Roller Bearings (CRB).\u00a0 In a few instances there may be deep groove type bearing and an occasional cup and cone. Their installation is usually straight forward and they are not going to be discussed in this article.<\/p>\n

Angular Contact Bearings (ACB) can handle axial and radial loads and are considered thrust bearings. However, they can only handle axial loading in one direction; so they are always used in pairs. Roller bearings have tremendous radial capacity; but zero axial capacity. So if your spindle uses a CRB it will also have at least one pair of ACBs.<\/p>\n

Because we warranty all of our work HST only uses top name brand bearings purchased from authorized distributors. We simply can\u2019t take the chance that an inferior bearing will fail prematurely. These bearings have one thing in common; they are expensive. However, the DIY guy may want to take a chance and use some \u201coff brand\u201d bearings. Depending on the spindle, the price difference could be over a thousand dollars.<\/p>\n

If you have a problem locating a bearing give us a call. We may be able to help you find a source and assist with spindle bearings installation.<\/p>\n

About Angular Contact Bearings<\/strong><\/p>\n

High performance CNC spindles use Super Precision\u00a0ABEC 7<\/a>, ABEC 9 or P4 spindle bearings. For a long time these were purchased as a matched set. \u00a0We always prefer matched sets. However, today matched sets are becoming more difficult to find and there is an industry movement toward P4 singles. \u00a0The theory is that any P4 bearing will be within the tolerance specification for matched set.<\/p>\n

As noted these Angular Contact Bearings (ACBs) can only resist axial loads in one direction. For this reason they must be used in multiple bearing arrangements to handle thrust loads in both directions. \u00a0These bearings come configured in a number of different arrangements. To get started let\u2019s take a look at an angular contact bearing.<\/p>\n

\"NSK<\/p>\n

This is a typical angular contact bearing configuration. In this example the angular contact surface is only on the outer race. Some series have the angular surface on the inner race and some have it on both races such as ball screw support bearings which have their own set of considerations.<\/p>\n<\/div>\n

The first thing to know is that ACBs have a\u00a0front and a back<\/strong><\/em>. It is import to be able to identify which side is which. Most often bearing nomenclature is printed on the back of the bearing. But that is not always the case so it is good to be able to identify which side is which by looking at the bearing. If a bearing is installed backwards the spindle will not perform satisfactorily and the bearing is likely to be ruined.<\/p>\n

Note in the diagram that the bearing can resist thrust on the shaft pushing from front to back. If any significant thrust is applied back to front the bearing can separate and be ruined. \u00a0It is easy to see why when you look at the cross section.<\/p>\n

Getting the Right Bearing<\/strong><\/p>\n

The bearing part number can specify a multitude of parameters including the following:<\/p>\n

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