Most people know that bearings are used to reduce wear between moving machine parts. Likewise, most are familiar with basic anti-friction bearings, like ball or roller bearings. However, when it comes to the hydrostatic variety, you might find yourself asking, "What is a hydrostatic bearing?"

Hydrostatic bearings are a type of plain bearing that maintain a film-like oil (or other lubricant) clearance between moving parts. Typically, movement and high pressure is involved in forming and maintaining the oil film. This makes hydrostatic or hydrodynamic bearings ideal for heavy load applications. Hydrostatic bearings serve automotive, industrial and other heavy duty applications.

Below are the main product types available from companies that manufacture hydrostatic bearings:

1. Circumferential groove hydrostatic bearings

2. Multiple groove hydrostatic bearings

3. Pressure hydrostatic bearings

Action Steps
The best contacts and resources to help you get it done

Buy from hydrostatic bearing firms that will work with you to select the right product

Bushings, shoulder screws and bolts, roller bearings and ball bearings are more common and standardized than hydrostatic bearings. Look for hydrostatic bearing companies that have been in the business a long time, know their own products, and are willing to work with you to ensure you buy hydrostatic bearings that fit your specific applications.

I recommend: Orion is a fine hydrostatic bearing company to start with if you need to fit industrial and marine applications. They have lots of information on their website and welcome you to contact them. Morgan Bronze Products sells their bearings in numerous compositions besides bronze. They are a customer-oriented company that invites you to visit their facilities in person.

Do some price comparisons at other manufacturers of hydrostatic bearings

Especially once you know what you need, there's nothing stopping you from shopping multiple companies to get the best prices. Just keep in mind that if you want continued support and service, stick with a quality company, not just the one with the lowest price.

I recommend: SKF sells many types of plain bearings, as well as lubrication systems. Industiral Drive Components prides themselves in finding whatever type of bearing you need. They service a wide array of industries.

Refurbish and maintain your hydrostatic bearings

With strong spindles and non-contacting movement, hydrostatic bearings are definitely on the durable end of the scale. However, they are neither invincible nor impervious to grime. Before removing and replacing parts, investigate the cost of hydrostatic bearing repair and refurbishment.

I recommend: AHR International will put just about any type of bearing back to work. The Bearing Service Company is another good choice; they've been in business since 1933.

Tips & Tactics

Helpful advice for making the most of this Guide

• •  Hydrostatic bearings usually produce some heat due to oil shear. Take this into account if your application is temperature sensitive.
• •  Hydrostatic and hydrodynamic bearings are not fully effective until part movement reaches full speed. So, do not use hydrostatic bearings for machine parts with fast startups.