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 isnt 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.

Features:

Class leading performance and sleek, contemporary styling
Excellent dynamic and high static load performance
Less than half the friction of the nearest competitor
Suits attachment to 14mm (9/16) wide mast collar post
Removable 8mm (5/16) clevis pin at head
Central hub hole can be used as a becket take-off or tie-up point

Applications:

Ideal for mainsheet, halyard and spinnaker sheet applications on boats to 11m (36ft).
Various control line applications on larger yachts.
Alloy sheave models are available for use with wire.

Materials:

Sheaves: U.V. stabilised Acetal
Cheek plates & cleat arms: Aluminium alloy
Ball Bearings: High compression strength carbon black Acetal
Shackle, post & hub: Grade 316 stainless steel
Padeye & snap shackle: Grade 15-5PH stainless steel
Snap shackle: Grade 15-5PH investment cast stainless steel
Cleat: Fibre reinforced composite
Pin: 2205 stainless steel

Note:* Full block rated load can only be achieved with uniformly distributed load across full length of clevis pin. ie. 14mm (9/16″) diameter mast collar post or 14mm (9/16″) wide mast collar plate/tang

Part Number
Sheave
Max. Rope
Max. Cable
Pin
M.W.L.
B. L.
Weight

RON-RF64108A
60mm
12mm
–
8mm
*1000kg
*2000kg
182g