The rotary kelly is manufactured in two basic configurations, square and hexagonal.
Each kelly meets the mechanical specifications listed in API Spec 7 and are available in four standard lengths:
- 37 feet (11.3m) overall length with a 34 foot (10.4m) working space
- 40 feet (12.2m) overall length with a 37 foot (11.3m) working space
- 46 feet (14.0m) overall length with a 43 foot (13.1m) working space
- 54 feet (16.5m) overall length with a 51 foot (15.5m) working space
Hexagonal or Square Kellys
Kellys are made from AISI 4145H modified alloy bars which are quenched and tempered to full length. A hardness range of 285 to 341 BHN and a minimum impact value of 40 ft-lbs are maintained one inch below the surface at room temperature. All ends and center drive sections are machined. The kellys are precision-trepanned to provide true bores. Command Energy kellys are drifted to API specifications and all connections are precision-machined and quality-assurance inspected. Note: All Command Energy kellys are completely integral.
- Hexagonal or Square Kelly
- Nominal Size
- Size and type of Top connection
- Size and type of Bottom connection
- Top upset OD
- Bottom upset OD
- Plain shipping scabbards are available