Self-Clinching Fastener Installation Do’s And Dont’s
- Do provide a mounting hole of a specified size for each fastener.
- Do install the fastener into the punch side of the sheet.
- Do make certain that the shank (or pilot) is within the hole before applying installation force.
- Do apply squeezing force between parallel surfaces.
- Do apply sufficient force to totally embed the clinching ring around the entire circumference and to bring the shoulder squarely in contact with the sheet. For some fasteners, the installation will be complete when the head is flush with the panel surface.
- Don’t attempt to install a 300-series stainless steel fastener into a stainless steel sheet.
- Don’t install steel or stainless steel fasteners in aluminum panels before anodizing or finishing.
- Don’t deburr mounting holes on either side of the sheet before installing fasteners – deburring will remove the metal required for clinching the fastener into a sheet.
- Don’t install a fastener closer to the edge of the sheet than the minimum edge distance indicated by the manufacturer – unless a special fixture is used to restrict bulging of the sheet edge.
- Don’t over squeeze. It will crush the head, distort threads, and buckle the sheet. Approximate installation forces are listed in performance data tables. Use this info as a guide. Be certain to determine optimum installation force by test prior to production runs.
- Don’t attempt to insert the fastener with a hammer blow – under any circumstances. A hammer blow won’t permit the sheet metal to flow and develop an interlock with the fastener’s contour.
- Don’t install a screw in the head side of the fastener. Install from the opposite side so that the fastener load is toward the sheet. The clinching force is designed only to hold the fastener during handling and to resist torque during assembly.
- Don’t install fastener on the pre-painted side of the panel.
Prepare properly sized mounting hole in sheet. Do not perform any secondary operations such as deburring.
Place shank of nut into mounting hole, preferably the punch side.
With punch and anvil surfaces parallel, apply squeezing force until the head of the nut comes into contact with the sheet material.