Collars holds and position the centralizers
used for centralizing the casing pipe in the well bore.
There are basically two types of Stop Collars. They are
either Hinged or Slip on - rolled welded.
The locking arrangement in the Hinged type is by a Single
Bolt or Set Screws or by two Spiral Nails. The other is
the Slip on type rolled welded in which the locking arrangement
is by a row of Set Screws.