How to Specify Custom Bearings – A Step-by-Step Guide for Procurement and Engineering Teams

Standard catalog bearings cannot always satisfy unique design requirements — special dimensions, unusual load profiles, or specific preload conditions may demand custom solutions.

Step 1: Define basic dimensional requirements

The simplest path to a custom bearing begins with precise dimensions. Provide the following:

• Bore diameter (d) — the inner ring‘s inside diameter, in mm

• Outer diameter (D) — the outer ring‘s outside diameter, in mm

• Width/height (B) — bearing width for radial bearings, height for thrust bearings

• Chamfer dimensions (r) — corner radii for housing and shaft clearance

If your design references an existing bearing with modifications, include the base model number. This greatly accelerates the engineering review process.

Step 2: Specify load and performance requirements

Bearing design depends fundamentally on application loading. Provide:

• Load characteristics — radial load (kN), axial load (kN), moment load (kN·m), static vs. dynamic loads

• Speed requirements — maximum rotational speed (RPM) for bearing inner ring rotation

• Precision grade — P5, P4, or P2 for precision-critical applications

• Rigidity expectations — deflection limits under specified loading (optional but helpful)

• Operating temperature range — min/max expected temperature for material and lubricant validation

• Lubrication method — grease, oil mist, or splash feed

If any parameters have not been fully characterized, provide a complete set of finite element analysis (FEA) results or stress calculations [4†L19-L24].

Step 3: Define material and treatment preferences

• Bearings for highly corrosive environments — ZnNi plating provides up to 1,000 hours of Neutral Salt Spray (NSS) resistance

• Bearings for high-temperature applications — retain dimensionally stability at elevated temperatures with specialized steel grades and heat treatment

• Bearings for low-friction requirements — PTFE coatings or solid lubricants reduce friction coefficient without external lubrication

If uncertain about optimal material for your application, provide environmental conditions and let the manufacturer recommend from their material library.

Step 4: Provide application context

Understanding where the bearing will be used helps engineers validate design assumptions:

Application category — rotary table, robot joint, spindle, linear guide, etc.
Equipment type — CNC machine, industrial robot, medical device, precision instrument
Duty cycle — continuous vs. intermittent operation, expected cycles per day
Mounting configuration — shaft and housing fits, adjacent component interfaces

Why Ouna Bearing excels at custom specifications

At Luoyang Ouna Bearing, we accept small to medium batch custom orders across all product lines: crossed roller bearings (ORA, ORB, ORE, ORU, ORAU, ORBH, OSX, OXSU, OXU, ORBS series), ORT series rotary table bearings, precision four-point contact ball slewing bearings, high-precision thrust cylindrical roller bearings, and bearings for humanoid robots. Provide your drawings or technical specifications, and our engineering team will handle the rest — developing non-standard sizes, unique preload settings, and application-specific profiles.

Ready to specify your custom bearing? You can send an inquiry directly with the above points filled in (maximum completeness to speed up preliminary design). Our engineering response typically arrives within 48 hours — including feasibility assessment and initial quotation. Contact us to begin your custom bearing project today — backed by our experience in serving precision equipment manufacturers worldwide.