ID grooves are used to hold bearings and require the correct-sized tool that is slightly smaller than the bore or counterbore size. The groove depth should match any measurements provided for the bore, or be twice as deep as a reference depth for grease grooves by touching the inside and cutting inwards.

1. How to make ID grooves
ID grooves are used to put rings to hold bearings
find the right tool and incert for the job, it has to be the
right size or a little smaller.
If the groove has measures, (example 3.440 – 3. 430 ) rest
this measure to the ID of the bore or counterbore and that is
the measure that you have to go in.
If the measure is only a reference (for grease grooves)
example 1/16 deep you must touch the inside of the bore or
C bore and go in double.