Baoci Precision: Single-Row Angular Contact Ball Bearing Face Difference & Preload Guide

May 4, 2026

CXE / Baoci Technical Standard

Single-Row Angular Contact Ball Bearings (AC Series):
Protrusion & Axial Clearance Data

Understanding Protrusion (Face Difference) & NSK Compatibility

In the precision matching of single-row angular contact ball bearings, the Protrusion —also known as the face difference between the inner and outer rings under a specific axial test load—is the most critical parameter. It directly determines the preload, rigidity, and running accuracy of the bearing assembly.

100% NSK Interchangeability: We are proud to state that all CXE Angular Contact Ball Bearings (now officially operating under the Baoci brand) are engineered and manufactured to the exact internal geometry and face difference standards as Japanese NSK bearings. This makes our AC series (25° contact angle) a perfect 1:1 drop-in replacement for NSK in high-precision industrial applications.

Engineering Note: According to our design standards, the Axial Clearance (mm) is strictly equal to twice the Protrusion amount (μm). The table below outlines the dynamic contact angle ao and face difference under various loads.

Bearing Model	Ball Size mm	Ball Qty	fi	fo	B	Original Angle	Test Load N	Test Load KG	Loaded Angle ao	Axial Clearance mm	Protrusion um
7000 AC	4.763	9	0.523	0.52	0.043	25°	9.8	1.00	25.30°	0.002	1
7000 AC	4.763	9	0.523	0.52	0.043	25°	49	5.00	25.87°	0.007	3
7000 AC	4.763	9	0.523	0.52	0.043	25°	98	10.00	26.34°	0.011	5
7001 AC	4.763	10	0.523	0.52	0.043	25°	9.8	1.00	25.28°	0.002	1
7001 AC	4.763	10	0.523	0.52	0.043	25°	49	5.00	25.81°	0.006	3
7001 AC	4.763	10	0.523	0.52	0.043	25°	117.6	12.00	26.41°	0.011	6
7002 AC	4.763	12	0.523	0.52	0.043	25°	9.8	1.00	25.25°	0.002	1
7002 AC	4.763	12	0.523	0.52	0.043	25°	78.4	8.00	25.97°	0.008	4
7002 AC	4.763	12	0.523	0.52	0.043	25°	137.2	14.00	26.38°	0.011	6
7003 AC	5.556	12	0.523	0.52	0.043	25°	9.8	1.00	25.20°	0.002	1
7003 AC	5.556	12	0.523	0.52	0.043	25°	88.2	9.00	25.86°	0.008	4
7003 AC	5.556	12	0.523	0.52	0.043	25°	147	15.00	26.19°	0.011	6
7004 AC	6.350	12	0.523	0.52	0.043	25°	9.8	1.00	25.18°	0.002	1
7004 AC	6.350	12	0.523	0.52	0.043	25°	78.4	8.00	25.68°	0.007	4
7004 AC	6.350	12	0.523	0.52	0.043	25°	235.2	24.00	26.35°	0.014	7
7005 AC	6.350	14	0.523	0.52	0.043	25°	9.8	1.00	25.16°	0.002	1
7005 AC	6.350	14	0.523	0.52	0.043	25°	117.6	12.00	25.79°	0.008	4
7005 AC	6.350	14	0.523	0.52	0.043	25°	235.2	24.00	26.23°	0.013	7
7006 AC	7.938	14	0.523	0.52	0.043	25°	9.8	1.00	25.13°	0.002	1
7006 AC	7.938	14	0.523	0.52	0.043	25°	98	10.00	25.53°	0.007	3
7006 AC	7.938	14	0.523	0.52	0.043	25°	245	25.00	25.95°	0.013	6
7008 AC	7.938	18	0.523	0.52	0.043	25°	9.8	1.00	25.11°	0.001	1
7008 AC	7.938	18	0.523	0.52	0.043	25°	117.6	12.00	25.50°	0.007	3
7008 AC	7.938	18	0.523	0.52	0.043	25°	392	40.00	26.09°	0.014	7
7010 AC	9.525	18	0.523	0.52	0.043	25°	19.6	2.00	25.11°	0.002	1
7010 AC	9.525	18	0.523	0.52	0.043	25°	245	25.00	25.64°	0.010	5
7010 AC	9.525	18	0.523	0.52	0.043	25°	686	70.00	26.23°	0.020	10
7015 AC	12.70	20	0.523	0.52	0.043	25°	19.6	2.00	25.10°	0.002	1
7015 AC	12.70	20	0.523	0.52	0.043	25°	490	50.00	25.65°	0.014	7
7015 AC	12.70	20	0.523	0.52	0.043	25°	1450	147.96	26.29°	0.027	14
7020 AC	15.88	22	0.523	0.52	0.043	25°	19.6	2.00	25.08°	0.002	1
7020 AC	15.88	22	0.523	0.52	0.043	25°	784	80.00	25.63°	0.017	8
7020 AC	15.88	22	0.523	0.52	0.043	25°	2372	242.00	26.25°	0.033	17

* Note: Data extract represents low, medium, and high load test points for key models from 7000 AC to 7020 AC. Full engineering matrices are applied across all 5,000+ SKUs.

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