Keck Spherical Joint Clamp (Pinch Clamp) S/S - No.18

This Keck spherical joint clamp (pinch clamp) is made from stainless steel and locks glass ball-and-socket connections so they stay leak-free.

Spherical joint pinch clamps (also called ball joint clamps) securely lock standard glass ball-and-socket joints and O-ring fittings. Made from stainless steel, they spread pressure evenly across the joint, which prevents leaks, pressure drops and joints coming apart during chemical synthesis, distillation and reflux setups.

Please note this range is not 304 (18/8) stainless steel.

Sizes and Specifications

The range comes in four sizes, matched to the standard ball diameters of laboratory glassware:

• 18# clamp: For small to medium apparatus with a #18 ball joint (for example 18/7 or 18/9 joints). Standard spring tension grip.
• 28# clamp: The standard size for mainstream chemistry setups with a #28 ball joint (for example 28/12 or 28/15 joints). Includes a locking screw.
• 35# clamp: A heavy-duty size for high-volume distillations with a #35 ball joint (for example 35/20 or 35/25 joints). Includes a locking screw.
• 50# clamp: The largest size, for large glass plants and pilot reactors with a #50 ball joint. Includes a reinforced heavy-duty locking screw.

Key Product Features

• Stainless steel: Good resistance to lab acid vapours, solvents and accidental chemical splashes (not 304 (18/8) stainless steel).
• Screw-type locking nut: Sizes 28#, 35# and 50# have a setting screw, so you can fine-tune the clamping force and it won't slip in high-vibration setups.
• Glass-safe pressure: Contoured twin fork arms grip the outer lip of the joint evenly. This gives a gas-tight and liquid-tight seal without creating stress points that can crack expensive glassware.
• High thermal tolerance: Handles the temperature changes of continuous boiling, vacuum distillation and cold-trap condensation.
• Product of China

Recommended Applications

• Securing flexible connections between distillation flasks, fractionating columns and receivers, where rigid ground-glass joints can snap.
• Linking gas delivery lines and vacuum manifolds in organic chemistry and university physics labs.
• Keeping glass seals secure in rotary evaporators and environmental sampling setups.