Flat Sealing Shim Washer

The Flat Sealing Shim Washer fills gaps between components and keeps fasteners tight under vibration or load, so its single most important property is accurate thickness. It is punched from SPCC, SUS304, pure copper or 65Mn, with PTFE composite and aluminum materials on offer. The ultra-thin series runs 0.1–0.5 mm with thickness tolerance held to ±0.02 mm, while the full custom range spans 0.05–2.0 mm. Standard structure covers flat washers, wave washers and locking washers, with special-shaped and combined washer structures available. Inner-hole tolerance is +0.03 / 0 mm and outer-diameter coaxiality is ≤0.05 mm, so the washer slides onto the bolt and stays concentric. Hardness is controlled to HV180–220 for flat washers and HV300–380 for spring washers, with zinc, passivation and plain stainless finishes.

A shim washer that varies in thickness by more than a couple of hundredths of a millimetre defeats its own purpose - the bolt either over-compresses or goes loose. Keeping die clearance and tooling condition stable is what holds the ±0.02 mm ultra-thin thickness and ≤0.05 mm coaxiality consistent across an entire batch, so a buyer can shim to a designed gap without sorting parts one by one. Tight batch control across the 0.05–2.0 mm range also lets one shim program cover both ultra-thin precision washers and standard load-bearing flat washers under the same quality standard.