Excuse Me, Could You Give Me a Grommet Check?
by Jan Meyer
Grommets are used on a container's closing flaps. The closing loop is routed through the grommets and held in place by the pin. Most newer containers use stainless steel grommets. These grommets are slightly harder to set. Inspect the grommets for complete setting. They should be very snug against the material.
If the grommet is not set completely a suspension line may snag the edge of the grommet. This could cause a malfunction and may prevent the main from separating after a cutaway. Do not jump a rig that has improperly set grommets. Have a rigger replace the grommets.
Older containers may have brass grommets. Brass grommets wear out. Pins can dig grooves into brass grommets. Pull forces will increase because of the increase in contact surface area between the pin and grommet. Grooves can inhibit lateral movement of the pin as it's being pulled, that can increase pull forces. Brass grommets corrode too. Corrosion can dramatically increase pull forces, especially if the pin hasn't been moved recently.
Discoloration of the brass is a sign of corrosion. Older containers had brass grommets installed everywhere. Any brass grommet located on the top flap of either the main or reserve container should be replaced with stainless steel grommets. A special tool is required to install stainless steel grommets. If your rigger doesn't have it, then at least get worn brass grommets replaced by new brass grommets. Keep an eye on the wear of the new grommets, too. Stainless steel grommets will last longer, but are harder to install because they crack more often than softer brass grommets.
Riggers can shave the barrel of the grommet on a grinder before installation in thin material to reduce the likelihood of cracking. Always check to ensure that the barrel rolls over completely and doesn't leave a sharp edge. Both stainless steel and nickel plated brass grommets are silver.
Nickel plated brass grommets are very shiny and stainless steel are dull. Stainless steel grommets are also more expensive, 35¢ as compared to 14¢ for nickel plated brass and 13¢ for brass spur type grommet and washer, size 0. Riggers may refer to Section 7.47 Grommet Replacement on pages 424 to 426 of The Parachute Manual
Technical information: courtesy of Sandy Reid of Rigging Innovations
Originally published in Sport Parachutist's Safety Journal V1, #3 Sept./Oct. 1988.
Dedicated to enhancing sport parachuting safety by disseminating information about equipment, environments and human factors.