Drill Bushings and Flat Products
A drill bushing guides the drill so the hole lands where the print says. Flat products - wear plates, backing plates and tool blanks - take the sliding and impact load so the working surface does not.
These are the two halves of holding a hole on location: the bushing controls the drill, and the flat stock the bushing sits in controls the position.
Start with the function
Drill bushings
Press-fit and slip-fit bushings guide the drill in a jig, fixture or die. Press-fit is the default where the bushing stays put; slip-fit where it has to come out for sharpening or a change of drill.
Flat stock and wear plates
Lamina flat stock comes in standard thicknesses for wear plates, backing plates and stripper plates - the surfaces that take the sliding contact in a die.
Wear products
Wear products are the replaceable surfaces in a die: the parts you expect to consume and change rather than rebuild around.
What to look for
Drill bushings. Sized by three numbers: the ID that fits the drill, the OD that fits the fixture bore, and the head style. Headless bushings sit flush in thin plates; headed bushings carry a flange so the bushing cannot be driven through under load. The ID is hardened and ground so the drill is guided rather than scored.
Press-fit versus slip-fit. A press-fit bushing is installed with an interference fit and removed by pressing out. A slip-fit bushing runs in a liner and lifts out by hand, which is what you want when the bushing has to be changed between operations or resharpened.
Flat products. Flat stock is supplied in standard thicknesses for cutting into wear plates, backing plates and stripper plates. Specify by thickness, width and length, and by whether the plate carries a ground working surface.
Wear plates. Wear plates are sacrificial by design. They take the sliding contact between moving die members and are replaced long before the die shoe itself shows wear. Checking them is cheaper than repairing the shoe.
