4145H Forged HDD Crossover Sub / Protection Sub, API 7-1 HDD Saver Sub for Horizontal Directional Drilling

Crossover Sub (Protection Sub) is a short heavy-duty tubular component used in Horizontal Directional Drilling (DISCO DURO) drill string. It is also known as Saver Sub in drilling industry.
It is installed between rotary head / drill pipe and downhole tools. Its two ends are machined with different thread connections to adapt mismatched thread sizes/types between drill string components.
Main function
1. Transfer torque, axial pull and mud circulation during pilot bore and pullback.
2. Protect expensive drill pipe, rotary head and downhole tools: Concentrate thread wear onto this replaceable short sub, so that costly main drill string threads avoid frequent damage.
3. Bridge incompatible API or HDD proprietary thread connections in BHA.
Manufactured from forged alloy steel, quenched & tempered. Thread surface treatment: phosphating / copper plating for anti-galling. Designed and inspected per API 7-1 & DS-1 standards.
Principales parámetros técnicos

Common thread combinations for HDD:
– 3-1/2 Reg × NC38
– NC38 × NC50
– NC50 × 4-1/2 Reg
– Custom HDD machine proprietary threads (Vermeer, Ditch Witch etc.)
Product Photo