Hitachi Needle Roller D8x20 - 313-421

Hitachi 313421 — Needle roller D8×20 (original Hitachi)

Restore smooth operation to a Hitachi demolition/rotary hammer with this original Hitachi needle roller, part number 313421. It’s a precision needle roller specified D8×20 (8 mm diameter × 20 mm length) and is supplied as an individual replacement component.

Purpose and fitment notes: this needle roller sits in the hammer’s bearing/roller assembly to reduce friction between rotating parts and wear in the drive mechanism — a small, inexpensive part that prevents binding and noise when worn. Check your tool’s parts diagram for the exact installation location (appears as the roller item in the exploded view).

Example models this part fits (not exhaustive) — typical compatible Hitachi/Hikoki demolition and rotary-hammer models:

- DH40MA, DH40MB, DH40MR, DH40MRY

- DH45MR

- DH50MB, DH50MRY, DH50MR

- H45MR, H45MRY

- H60MR, H60MRV.

Easy swap: replace the worn roller with this exact Hitachi part to restore proper bearing action and extend the life of the tool’s internal drive components.