You can use t-nuts for a lot of reasons. A t-nut specifically is for screwing machine screws into wood. This particular use case is using that machine screw as a leveler, but it’s not the only case.
Sometimes you just want a large, solid bolt to hold things together, but allow them to be taken apart. In those cases I try to put the t-nut the other way around so assembly tightens the nut.
You can use t-nuts for a lot of reasons. A t-nut specifically is for screwing machine screws into wood. This particular use case is using that machine screw as a leveler, but it’s not the only case.
Sometimes you just want a large, solid bolt to hold things together, but allow them to be taken apart. In those cases I try to put the t-nut the other way around so assembly tightens the nut.
They’re used a lot in cheap pressboard furniture, to keep the screws from stripping out in the weak “wood.”