flange nut / steel / self-retaining
Avibank Mfg., Inc
Self Retaining Nuts
Nuts for self-retaining bolts are available in a wide variety of designs and materials, with or without scallops which prevent backing off of the nut. Due to the locking elements, most self-retaining bolts require counter-bored nuts or spacers. Avibank manufactures various spacer designs which eliminates the requirement of using a special nut.