Ronstan RF74100AW Series 75 Core Block - Single Aluminium Rope/Wire Sheave

Core Blocks are a true all round solution. A tuned 2-stage bearing system provides excellent performance across the full working load range with an integrated thrust bearing feature and the resilience to handle high dynamic or static loads. Acetal sheave, alloy cheeks and stainless fixings complete the durable package. For reliability and a long service life, these blocks are the right choice for sheets, halyards and control line applications for cruising and racing. 

Universal Bearing -

Dynamic and high static load performance

The Ronstan Universal Bearing incorporates our proven 2-stage bearing system

Stage 1 - Under moderate loads, Acetal ball bearings ensure minimum friction.

Stage 2 - Under heavy loads, where deformation of ball bearings alone would result in increased friction, a sliding Acetal bearing on a polished stainless steel race takes over, maintaining low friction performance.

Additionally the ball bearings are configured to act as a thrust bearing between the sheave and cheeks, preventing the sheave from rubbing on the cheeks and causing friction when the line lead in and out of the block isn't perfect. Particularly important for cheek blocks.

Alloy cheek plates

Block cheeks are manufactured from the highest quality alloy for maximum strength. Material optimisation and the cut-away design minimises weight and allows easy fresh water rinsing of salt and debris from the bearings.  Cheek design has been further styled with flaring at the block throat and reduced gap between the cheek and sheave, minimising rope wear.

 

Universal head

The head assembly incorporates a brass bearing washer to provide smooth 360 degrees rotation of the post and shackle. A set screw arrangement allows the head to be locked at 0 degrees or 90 degrees.

Shackles are high quality forged grade 316 stainless steel. Acetal and aluminium sheave optionsselected models are available with an aluminium sheave which has a deep groove profile specifically made for use with wire.

Applications

• Ideal for use on mainsheet, spinnaker sheet, vang, halyard and backstay applications on boats up to 14m (46ft).
• General applications on larger yachts.
• Alloy sheave models are available for use with wire.

Materials

• Sheave: U.V. stabilised acetal or anodised aluminium (AW models).
• Cheek plates: Aluminium alloy
• Ball Bearings: High compression strength carbon black acetal.
• Shackle, post and hub: Grade 316 stainless steel.

Spare Parts

Product No.	Description
RF324	Springs,
RF618A	5/16' pin dia., Standard Dee Shackles, Coined pin head,

Features:

• Class leading performance and sleek, contemporary styling
• Excellent dynamic and high static load performance
• Less than half the friction of the nearest competitor
• Durable alloy Rope/Wire sheave
• Universal head with full 3-axis articulation
• Shackle head lockable at 0 or 90 degrees
• Central hub hole can be used as a becket take-off or tie-up point

Specifications:

Sheave diameter	75 mm
Max. Rope diameter	14 mm
Max. Cable diameter	8 mm
Pin diameter	8 mm
M.W.L.	1500 kg
B. L.	3000 kg
Weight	432 g