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57mm Aluminum Low-Load Double Block — Swivel

57mm Aluminum Low-Load Double Block — Swivel

Part No. 3228

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) 1250 kg

Maximum working load (lb) 2755 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. Low-load blocks have red isolators. They use Torlon® rollers and 316 stainless steel shackles. Standard blocks have 17-4 PH stainless headposts. 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)132 mm
Length (in)5 3/16 in
Weight (g)342 g
Weight (oz)12.05 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)1250 kg
Maximum working load (lb)2755 lb
Breaking load (kg)2500 kg
Breaking load (lb)5510 lb
Composer Export9421256141311137108BOM IDDescriptionQty12115NP SHKL. 8MM D12AL-3706 CENTER CHEEK DBL.13AL-3707 ALPHA CHEEK DBL.14AL-3708 BETA CHEEK DBL.15H-34389A SHV. ASSM.26HBB85 ROLLER CAGE ASSM.28HFS796 FST. 4 X .7 X 12MM SHCS49HFS797 FST. 4 X .7 X 35MM SHCS17HFS1273 FST. 5 X .8 X 16MM SHSS110MP-3026 FST. ISOLATOR511MP-3033 HD. POST COLLAR112MP-3042 HD. POST COLLAR W/HOLE113MS-195 57MM SHEAR TUBE214SP-067 HEAD POST1tooltip
ID BOM Qty Price
2115 - more info $21.25
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8mm "D" Shackle

Forged stainless steel shackles are polished to a high luster and are stamped with the screw pin diameter. "D" shackles are the most common type of shackle. They are best suited for aligned attachment points.

HFS796 4 more info $0.32
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Fastener - M4 x .7 x 12mm Socket Head Cap Screw, Black

Fasten with M4 hex wrench.

HBB85 2 more info $29.95
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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 $28.05
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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 $37.45
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Headpost - 57/75mm Black Magic Block

Black Magic blocks have 17-4 PH stainless headposts.

MP-3033 1 more info $1.60
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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 $0.96
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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 $74.90
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Sideplate with Helicoils - 57mm Black Magic Double Block

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

AL-3706 1 more info

Center Sideplate - 57mm Black Magic Double Block

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

AL-3708 1 more info $74.90
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Sideplate - 57mm Black Magic Double Block

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

HFS1273 1 more info $1.85
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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 $1.28
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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 $15.25
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Shear Tube - 57mm Black Magic Double Block

The shear tube is a stainless steel reinforcement between sideplates.

F R E E   G R O U N D  S H I P P I N G

for orders over $100!

Valid on orders shipping within the United States

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