Hitachi 6685416 Chain Bar Clamp Nut

The Hitachi 6685416 Chain Bar Clamp Nut is a genuine OEM replacement component designed to secure the guide bar on compatible Hitachi chainsaws. The clamp nut is a small but safety-critical part — it maintains the tension and alignment of the bar and chain assembly during operation. A worn, stripped, or missing clamp nut can allow the bar to shift under load, creating a serious safety hazard and degrading cutting performance. Replacing it with an OEM part ensures the correct thread pitch, diameter, and material hardness that Hitachi engineered for the application.

Because this is a single nut sold individually, owners should check whether their chainsaw model uses one or two clamp nuts on the bar cover and order accordingly. Hitachi chainsaws typically use a combination wrench for bar and chain adjustments, and that same tool is all that is needed to swap this part. As with any hardware replacement on a chainsaw, it is good practice to inspect the bar studs and bar cover for damage or wear at the same time, since a new nut threaded onto a damaged stud will not hold torque reliably.