ROTARY AND HANDLING TOOLS - National Oilwell Varco

MBH1250 HINGED MASTER BUSHING
For the safe handling of heavy weight casing strings, including bit, in combination with the
corresponding landing strings a new series of rotary equipment, having a dedicated rating and
safety factor, has been developed.
• Casing sizes up to 24", string weights up to 1,000 sTon.
• 5.1/2" to 6.5/8" landing strings with dedicated drill pipe, string weights up to 1,250 sTon.
• Dual upset drill pipe, string weight up to 1,250 sTon.
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All standard pipe types and sizes with special #1, #2 and #3 master bushing bowls, string
weights up to 1,000 sTon.
Standard bit breaker plates. Maximum bit diameter 29.1/2".
CASING BUSHINGS
Height and internal diameters/tapers of casing bushing are 100% identical to standard NOV
Varco BJ 24" CB16542 casing bushing. Interfaces with standard 24" CMS-XL casing slips.
DRILLING BOWLS
Interfaces with standard API handslips featuring a 1: 6 taper.
When removed from MBH1250, a 29.1/2" diameter bit can pass through MBH1250, without the
need to remove the MBH1250 from the rotary table, due to throat opening of 30".
These bowls feature the standard MPCH bit breaker holes. Standard bit breaker plates, kelly
bushings, etc, fit into these holes. Interfaces with same torque backup blocks in MBH1250 as
above mentioned casing bowls for torque backup an assembly.
LSB1250 LANDING STRING BUSHING
To handle 1,000 sTon capacity landing strings, the MBH1250 can be dressed with the LSB1000
Landing String Bowl. Combined with the Special Design Landing String Hand Slips, the landing
string can be run up to loads of 1,000 sTon. The Landing String Slips grip the pipe with standard
inserts. Customers should always perform a crushing load calculation to determine the ultimate
safe working load of the system.
To handle 1,250 sTon capacity landing strings, the MBH1250 can be dressed with the LSB1250
Landing String Bowl. Combined with the Special Design Landing String Hand Slips, the landing
string can be run up to loads of 1,250 sTon. The 1,250 sTon capacity can only be achived with
landing strings with “dual upset” connections, i.e. the joint has two 18 degree tool joints. A 1,250
sTon capacity BX style elevator will be connected to the upper tool joint, while the lower tool
joint is suspended in the LSB1250 with special slips that have an 18 degree contour in the slips,
rather then inserts.
TEChNiCAL SpECiFiCATiONS
Description Size
Size Fits into 49.1/2" National rotary table (= 49.1/2" RST) as standard.
Height 20" (equal to a standard 37.1/2" MPCH Master Bushing)
Internal throat opening 30"
Maximum backup torque 500,000 ft.lbs
Rating axial 1,250 sTon
Rating axial w/ spreading load 1:6 taper 1,000 sTon
Lifting slings Can be handled (lifted) with standard lifting slings with certified latching hooks or
standard certified shackles.
WWW.NOV.COM
MBH1250 with drilling bowl and slips
MBH1250 with casing bushing
MBH1250 with drilling bowl
MBH1250 with LSB1250
landing string bushing and
LSS1250 landing string slip
BUSHINGS / SLIPS / CLAMPS
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