Wire size headed (H) press-fit drill bushings come in standard sizes that correspond to American Wire Gauge (AWG) sizes. The larger the wire size, the smaller the bushing. Standard-wall headed press-fit drill bushings have thicker walls and are typically sturdier than thin-wall headed press-fit bushings.Headed press-fit (H) drill bushings have an overhang, or head, that prevents them from being pushed through the drilling jig, making them ideal for applications where axial loads or vibration could move headless drill bushings. The bushings can be installed with the head projecting above the jig plate, or they can be countersunk so the head is flush with the jig plate's surface. Type H drill bushings are permanently pressed into the jig and are suitable for single-step drilling operations where the bushings will not need to be replaced. Drill bushings are installed into a drilling jig to guide, support, and position a drill or other cutting tool during metalworking tasks. They keep the cutting tool from wandering or bending as it enters the workpiece, maximize chip clearance, and minimize the risk of marring the workpiece or the jig. Specifications: Item: Headed Press-Fit Drill Bushing (H)Drill Bushing Wall Type: Standard WallHead Type: YesMeasurement System: WireInside Dia.: #8Decimal Equivalent: 0.199Drill Size: FInside Dia. Tolerance: +0.0002\"/+0.0006\"Outside Dia.: 1/2\"Outside Dia. Tolerance: +0.0017\"/+0.0014\"Bushing Code: HBushing Head Type: HeadedOverall Length: 1\"Head Dia.: 39/64\"Head Material: High Speed SteelHeat Treatment: Through HardenedMaterial - Machining: High Speed SteelRockwell Hardness: RC 62-64"