Rotary subs have two primary applications. They can be used to crossover from one connection size to another. They can also be used as a disposable component to extend the connection life of a more expensive drill stem member. Rotary subs are available with box x pin, box x box or pin x pin connections. The connections are protected by a phosphate surface coating that minimizes galling on initial makeup.

STRAIGHT OD SUB is used to connect drill stem members that have a similar outside diameter. The drill bit, downhole tools, heavy weight drill pipe and drill pipe can be crossed over using a straight OD sub.

REDUCED SECTION SUB is used to connect drill stem members that have different diameters that warrant the cross-sectional change necessary to accommodate different connections. This sub would be used to crossover large OD drilling tools or a tapered drill collar string.

SAVER SUB is used to extend the life of the Kelly by taking the connection wear each time it is made-up to a drill stem component. The saver sub connection is sacrificed because it can be easily repaired or inexpensively replaced. The saver sub can be equipped with a rubber protector to reduce BOP equipment and casing wear resulting from contact damage with a lower Kelly connection.


When ordering or requesting quotations on Rotary Subs, please specify: 
  1. Type required. 
  2. Nominal size OD 
  3. Bore ID 
  4. Tool joint OD 
  5. Length, size, type and location of connections. Example: NC 50 Box up x NC 50 Pin Down. 
  6. Cast or pressed-steel thread protectors 
  7. For reduced section subs, add: diameter of reduced section. 
  8. Length of reduced section: 8”, 12”, 18” or 24”. 
  9. For bit subs, add: float bore size and type. 
  10. For Kelly saver subs with protectors add: 
    1. Casing OD.
    2. Weight to properly size the casing protector.