BEARINGDEX
Deep groove ball

6404 bearing

20 mm bore, 72 mm outside diameter, 19 mm width (0.7874 × 2.8346 × 0.748 in).

Cross-reference 6404Decode a full part number

Dimensions

mminch
Bore d200.7874
Outside diameter D722.8346
Width B190.7480

Quick numbers

Pitch diameter dm46.0 mm
Section height (D − d)/226.0 mm
n·dm at 1,800 rpm82,800
n·dm at 3,600 rpm165,600

Compare against the maker's limiting speed. Speed calculator · L10 life

What the number means

6Deep groove ball
4Diameter series 4: heavy. Width series 0 is implied and left off.
04Bore code 04 × 5 = 20 mm

How each brand writes it

Same bearing, every maker's notation
VersionSKFFAGNSKNTNKoyoNACHI
Open640464046404640464046404
Shields both sides6404-2Z6404-2ZR6404ZZ6404ZZ6404ZZ6404ZZE
Contact seals both sides6404-2RSH6404-2RSR6404DDU6404LLU6404-2RS6404-2NSE
Contact seals both sides, C36404-2RSH/C36404-2RSR-C36404DDUC36404LLUC36404-2RSC36404-2NSE C3 Verify
Non-contact seals both sides6404-2RSL6404-2BRS Verify6404VV6404LLB6404-2RU Verify6404-2NKE Verify
Shields both sides, C36404-2Z/C36404-2ZR-C36404ZZC36404ZZC36404ZZC36404ZZE C3 Verify