Slewing bearing studs and nuts, slew drive and winch bolts, boom foot and A-frame pins and their keeper bolts, made in Houston to your drawings and specifications.
A lattice-boom offshore pedestal crane drawn round its slewing connection: a three-row roller slewing bearing with a 3,150 mm (124 in.) raceway, 3,432 mm across, held by 72 M42 studs through each ring. It comes apart the way a crew changes the bearing out: the slew drives are unbolted and drawn up clear of the ring gear, the outer ring nuts spin off and the upper structure lifts away, then the inner ring nuts come off and the bearing lifts off the pedestal flange. After that the keeper plates and pins come out and the boom, A-frame, winches and cab are stripped off the machinery deck. The bolting and pins we make are in colour. Press Solid view for a steel model, or Cutaway to see the rollers, the studs through both rings and the pedestal wall.
72 M42 through studs on a 2,958 mm bolt circle clamp the bearing's geared inner ring to the pedestal's top flange, with a nut and a hardened washer at both ends. Typically ISO 898-1 class 10.9 or an ASTM A320 low-temperature grade, with rolled threads. API Spec 2C asks for equal spacing round the full circle, a calculated fatigue life, impact-tested material and a controlled preload.
A second circle of 72 M42 studs on a 3,342 mm bolt circle runs up through both halves of the split outer ring and the base flange of the revolving upper structure. Every lift's overturning moment passes through them, so they are tightened evenly and their preload is re-checked in service.
Twelve bolts round each of the four slew drive flanges on the machinery deck; the drives' pinions turn the crane on the bearing's internal gear.
Six bolts through each foot of the main hoist winch into the machinery deck.
Six bolts through each foot of the boom hoist winch, which raises and lowers the boom over the A-frame sheaves.
Hold the operator's cab on its bracket at the front corner of the house.
Two large machined pins through the boom heel and the line-bored lugs on the house; the boom pivots on them.
Pin the A-frame's front legs and back stays to lugs on the house.
Four bolts through each keeper plate stop the boom foot and A-frame pins turning or walking out.
Slewing bearing studs, winch bolts, boom foot pins and the rest of an offshore crane's bolting, to your drawing. Send us your drawings and material spec.
Request a quote832-446-3442A generic pedestal crane, not any maker's design, and not to scale above the slewing connection: the pedestal and boom are drawn much shorter than they are. The bearing's rings, bolt circles, hole counts and gear follow a standard catalogue size of three-row roller slewing bearing, M42 is the stud size for its 45 mm holes, and the nuts and washers follow ISO 4032 and ISO 7089. The stud length and grades, the flange thicknesses, the section inside the bearing, the slew drives, winches, cab, pins and their bolt sizes and counts are typical or illustrative. Your drawings govern. We manufacture to your drawings and specifications.
Drawn round a standard-series three-row roller slewing bearing (3,150 mm raceway, 72 holes of 45 mm in each ring), with ISO 4032 nuts and ISO 7089 washers on M42 studs, and the swing-circle fastener rules of API Spec 2C.
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