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57mm Aluminum Double Block — Swivel, Becket

57mm Aluminum Double Block — Swivel, Becket

Part No. 3218

Sheave Ø (mm) 57 mm

Sheave Ø (in) 2 1/4 in

Maximum line Ø (mm) 12 mm

Maximum line Ø (in) 7/16 in

Maximum working load (kg) 1633 kg

Maximum working load (lb) 3600 lb

Black Magic Air blocks are a top favorite of Big Boat performance racers and cruisers. These lightweight, free-running, powerful performers are used for sail controls that see lots of action: mainsheet, runner, halyard, and spinnaker systems. A center cage keeps Torlon® roller bearings separated and parallel to reduce friction. Shackle blocks lock in two directions or swivel to keep line from twisting. Torlon is a registered trademark of Solvay Advanced Polymers L.L.C.
Sheave Ø (mm)57 mm
Sheave Ø (in)2 1/4 in
Length (mm)152 mm
Length (in)6 in
Weight (g)352 g
Weight (oz)12.43 oz
Shackle pin Ø (mm)8 mm
Shackle pin Ø (in)5/16 in
Maximum line Ø (mm)12 mm
Maximum line Ø (in)7/16 in
Maximum working load (kg)1633 kg
Maximum working load (lb)3600 lb
Breaking load (kg)3267 kg
Breaking load (lb)7200 lb
Composer Export210594713156141213118BOM IDDescriptionQty12116 SHKL. 8MM D HR12AL-3205 BKT. SPACER13AL-3707 ALPHA CHEEK DBL.14AL-3709 CENTER CHEEK DBL.15AL-3710 BETA CHEEK DBL.16H-34389A SHEAVE ASSM.27HBB85 ROLLER CAGE ASSM.28HFS1273 FST. 5 X .8 X 16MM SHSS19HFS796 FST. 4 X .7 X 12MM SHCS510HFS797 FST. 4 X .7 X 35MM SHCS111MP-3020 FST. ISOLATOR212MP-3033 HD. POST CLR.113MP-3042 HD. POST CLR. W/CUTOUT114MS-195 SHEAR TUBE215SP-067 HEAD POST1tooltip
ID BOM Qty Price
2116 1 more info $72.55
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8mm "D" Shackle — High Resistance

Forged stainless steel shackles are polished to a high luster and are stamped with the screw pin diameter. High-Resistance (HR) shackles are forged in 17-4PH stainless steel to handle high loads. They have an "HR" imprint for easy identification.

AL-3205 1 more info $45.00
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Becket Spacer - 57mm Black Magic Block, Becket

Use the becket to deadend line.

HFS796 5 more info $0.30
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Fastener - M4 x .7 x 12mm Socket Head Cap Screw, Black

Fasten with M4 hex wrench.

MP-3020 6 more info $1.00
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Fastener Isolator - 4mm SK HD

Dissimilar metals are isolated to prevent corrosion.

HBB85 2 more info $28.00
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Roller Cage Assembly - 57mm Black Magic Block

Center cage keeps Torlon® roller bearings separated and parallel to reduce friction.

H-34389A 2 more info $26.21
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Sheave Assembly - 57mm Black Magic Block

Sheaves are Hard Lube-anodized for maximum UV protection and a smooth surface. Captive Delrin® ball bearings carry side loads.

SP-067 1 more info $35.00
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Headpost - 57/75mm Black Magic Block

Black Magic blocks have 17-4 PH stainless headposts.

MP-3033 1 more info $1.50
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Headpost Collar Half - 57/75mm Black Magic Block

Headpost collar isolates dissimilar metals to prevent corrosion. Collar accepts set screw that fixes shackle in one direction or allows it to swivel.

MP-3042 1 more info $0.90
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Headpost Collar Half - 57mm Black Magic Double Block, Cutout

Headpost collar isolates dissimilar metals to prevent corrosion. Collar accepts set screw that fixes shackle in one direction or allows it to swivel.

AL-3707 1 more info

Sideplate with Helicoils - 57mm Black Magic Double Block

Sideplates are Hard Lube-anodized for maximum UV protection and a smooth surface.

HFS1273 1 more info $1.75
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Fastener - M4 x .7 x 8mm Stainless Steel Socket Head Shoulder Screw Cup, Black

Set screw allows shackle to be fixed or to swivel.

HFS797 1 more info $1.20
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Fastener - M4 x .7 x 35mm Socket Head Cap Screw, Black

Fasten with M4 hex wrench.

MS-195 2 more info $14.25
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Shear Tube - 57mm Black Magic Double Block

The shear tube is a stainless steel reinforcement between sideplates.

AL-3710 1 more info $72.00
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Sideplate - 57mm Black Magic Double Block, Becket

Sideplates are Hard Lube-anodized for maximum UV protection and a smooth surface.

AL-3709 1 more info $80.00
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Center Sideplate - 57mm Black Magic Double Block, Becket

Sideplates are Hard Lube-anodized for maximum UV protection and a smooth surface.