C-Serts are TAPS – they cut their way in. The integral pilot ensures they start straight. It’s just .003 – .004 smaller than the hole you have opened up.
If you need to remove a stuck bolt from a C-Sert, the L-H external threads prevent the C-Sert from backing out with the bolt.
The slots drive the C-Serts. They also clean up any damaged or defective bolt that gets used by mistake.
The ACME profile is far stouter than ordinary sharp crested threads. It prevents thread failure and pull-out.
Just like a standard tap, C-Serts have chip relief to reduce tool pressure, lands to support the tapping teeth, and flutes to clear chips.
This is classic tap geometry – cutting teeth, chip relief, lands and flutes. As chips form, they curl into the C-Sert’s hollow center for removal later.