Check the listing for details. GRAINGER APPROVED H404IW Drill Bushing,H,Drill Size Q 11G707. Condition: New. Listed at 11.43 USD. Headed Press-Fit Drill Bushing (H), Standard Wall, Headed, Letter, Q These headed (H) press-fit drill bushings come in standard letter sizes. The trade letter size for each drill bushing indicates its compatibility with other tools that have the same trade letter size. 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 bu.