What are self-tapping threaded inserts?
Self-tapping threaded inserts, probably better known as Rampa threaded inserts, are a type of nut that has a metric thread on the inside and a sharp thread with a coarse pitch on the outside.
As the name self-tapping threaded insert suggests, it is screwed into a pre-drilled hole. While screwing in, the sharp coarse external thread cuts firmly into the surrounding material. The drill size of the pre-drilled hole depends on the hardness of the material. Our handy drill size table provides guide values for this.
Self-tapping threaded inserts from Rampa® are available in many designs and sizes. For example, there are Rampa inserts with or without collar, various lengths, etc. The drive of the threaded inserts can also vary, for example there are versions without drive and versions with slotted, hexagonal (Allen) or Torx drive.
As standard, we supply self-tapping threaded inserts in steel or pressure-cast zinc. Other materials such as brass or stainless steel on request. Rampa® threaded inserts are available from M4 to M24, with sizes such as M6, M8, M10 and M12 being popular.
What are knock-in T-nuts?
An knock-in T-nut is best described as a flanged bushing with an internal metric thread. The flange can have several pronged tees. The pronged tees ensure that the nut does not twist during loosening or tightening of the bolted connection and the flange prevents the nut from being pulled through the wood. T-nuts are also referred to as drive-in nuts or blind nuts.
Installation is easy. T-nuts are mounted in a pre-drilled hole, with the threaded sleeve falling into the hole and the pronged tees driven into the material. Knocking in with a hammer is possible, but it is better to pull the T-nut into the wood while tightening the bolted connection. This prevents bent pronged tees and damage to the zinc coating.
T-nuts are available in galvanised steel as standard, stainless steel on request. T-nuts in sizes M4, M5 and M6 are often used to attach latches, surface-mounted hinges and handles, while sizes M8 and M10 are often used to mount castors or threaded rods.
