Drill Collars

Drill Collars
Drill Pipe
Heavy Weight Drill Pipe (HWDP)
drill collar image - Downhole Oil Tools, Inc.
DHOT Drill Collars are manufactured from 4145H MOD Q&T steel with a hardness range of 285-341 BHN.

All API connections comply with dimensional requirements specified in API Spec. 7 and guidelines presented in API RP7G. These connections are phosphate-coated to improve resistance to galling as well as “cold rolled” to provide longer fatigue life.

API stress relief groove pin and bore back box are available upon request.

DHOT Drill Collars are offered as slick or spiral and can include optional features; slip and/or elevator recesses (to improve handling time) and hard banding.

When ordering, please specify:

  • Drill collar OD
  • Drill collar bore ID
  • Length of drill collar
  • Slick or Spiral
  • Size and Type of Connections, example: NC 50 box up x NC 50 pin down
  • Cast or pressed steel thread protectors
  • Slip and/ or Elevator Recesses
  • Hard banding