Specifications

Dimensions below are the standard production range for clamps. Sizes are given as a selection hint only; please check the actual product.

Request custom specs

Clamp sizes

Type	Jaw opening (mm)	Stem length (mm)	Material	Suitable for
Universal clamp	10 ~ 60	150	Zinc alloy + silicone	Flasks, condensers, separating funnels
Universal clamp (large)	20 ~ 90	200	Zinc alloy + silicone	Large flasks, reaction vessels
Three-prong clamp	5 ~ 50	150	Stainless + silicone	Burettes, thermometers, electrodes
Flask clamp	20 ~ 60	200	Stainless + silicone	Round-bottom and distillation flasks
Double-head clamp	10 ~ 60	180	Zinc alloy + silicone	Two items held at once

Values are typical; reasonable tolerances apply between production batches. Please rely on actual measurement.

📌 Customization:
• Jaw opening and stem length selected to order
• Single head, double head and special angle designs available
• Heat-resistant sleeves available for use near heating sources

Product Description

1. Overview

Universal and flask clamps are the holding components of a retort stand, fixing glassware that would otherwise have to be held by hand. A universal clamp combines a body, an adjusting screw and a sleeved jaw; turning the screw changes the jaw opening, and the head can be swivelled so a vessel stands vertical or at an angle.

The inside of the jaw is lined with a silicone or rubber sleeve. This increases friction so the vessel cannot slide, and keeps metal away from the glass to avoid scratches and stress concentrations. The three-prong clamp grips at three points for even, steady support of round vessels, while the flask clamp is shaped to hold the neck of round-bottom and distillation flasks.

Common jaw openings run from 5mm to 90mm, covering burettes, thermometers and electrodes through to 1000mL flasks. When selecting, check both the jaw range against the diameter being gripped, and the stem bore against the rod diameter of the retort stand.

🔬 Types & Features:
Adjustable jaws — stepless screw adjustment to suit many diameters.
Silicone sleeve — grips firmly and protects the glass.
Three-point grip — even support keeps round vessels from slipping.
Swivel head — rotate the head to set the vessel angle.

2. Key Parameters

Body: zinc alloy or stainless steel with plated finish
Jaw opening: 5 to 90 mm depending on model
Sleeve: silicone or rubber
Types: universal, three-prong, flask and burette clamps
Design: single or double head with adjustable angle
Fitting: retort stands and boss heads

3. Material & Workmanship

Bodies are die-cast from zinc alloy or machined from stainless steel and finished by plating or coating to resist rust. Sleeves are moulded from silicone or oil-resistant rubber, staying elastic without cracking and holding their shape under long clamping loads.

Handling tip: make sure the sleeve covers the whole contact area and never let metal press directly on glass. Tighten only until the vessel stops moving.

Applications

Typical Uses

Holding condensers

keeping the joint aligned with the flask

Holding separating funnels

steady while layers settle and drain

Holding burettes

the three-prong clamp keeps them vertical

Holding flasks

preventing movement during heating and reflux

Industries

Chemical synthesis supporting routine glassware
Analytical testing securing titration and extraction set-ups
Teaching laboratories building basic apparatus
Pharmaceutical R&D steady support for pilot set-ups
Quality control assembling sample preparation apparatus

Selection Guide

Select by the item to be held

Item held	Suggested type	Notes
Burette, thermometer, electrode	Three-prong clamp	Three-point grip steadies slim items
Round-bottom, distillation flask	Flask clamp	Grips the neck with a non-slip sleeve
Condenser, separating funnel	Universal clamp	Adjustable width and angle
Large reaction vessel	Universal clamp (large)	Jaw opening up to 90mm

💡 Tips: Match the jaws — the gripped diameter should sit inside the jaw range with margin.
Sleeves first — a sleeve must always sit between metal and glass.
Moderate tightness — tight enough not to slide, not tight enough to crack a neck.
Check the bore — confirm the stem bore matches the retort stand rod.

Operation & Maintenance

Operation Guide

Clamps look simple, but clamp position and tightness decide how safe the set-up is. The steps below cover routine use.

Before Use

Check the clamp body for cracks and the screw for smooth travel
Confirm the sleeve is intact, not loose or hardened
Check the jaw range against the diameter to be gripped
Check the stem bore against the retort stand rod diameter
Have a boss head ready to join clamp and stand

Procedure

Fix the clamp to the retort stand rod with a boss head
Turn the adjusting screw to open the jaws slightly wider than the vessel
Place the vessel in the jaws so the sleeve covers the contact area
Tighten the screw gradually until the vessel no longer moves
Adjust the head angle so the vessel sits vertical or at the required tilt
Push the vessel gently to confirm no movement, then continue assembly

Cleaning & Care

Wipe reagent residues and water off clamps after use
Wash sleeves with water or a mild detergent
Replace sleeves as soon as they harden or crack
Add a little lubricant to the screw to keep it free
Store without crushing so the jaws keep their shape

💡 Lab veteran tips: Mount first, clamp second — fixing the clamp to the stand first makes alignment easier.
Avoid graduations — do not clamp over scale marks or joints.
Not too tight — over-tightening concentrates stress, which is risky on thin necks.
Sleeve inside — confirm the sleeve faces the glass on the inside of the jaw.

Care & Notes

Show care & notes

⚠️ Safety Notes

Correct tightness

too tight can crack glass, too loose lets it slide

Sleeve condition

replace any damaged sleeve before further use

Heat protection

use heat-resistant sleeves or reposition near heat sources

Load check

heavy vessels need large-jaw clamps and extra support

Do not

Clamp position: avoid graduations, joints and weak points on glassware

Universal Clamp & Flask Clamp

Specifications

Clamp sizes

Product Description

1. Overview

2. Key Parameters

3. Material & Workmanship

Applications

Holding condensers

Holding separating funnels

Holding burettes

Holding flasks

Selection Guide

Select by the item to be held

Operation Guide

Before Use

Procedure

Cleaning & Care

Care & Notes

Correct tightness

Sleeve condition

Heat protection

Load check

Need Universal Clamp & Flask Clamp?

Universal Clamp & Flask Clamp

Specifications

Clamp sizes

Product Description

1. Overview

2. Key Parameters

3. Material & Workmanship

Applications

Holding condensers

Holding separating funnels

Holding burettes

Holding flasks

Selection Guide

Select by the item to be held

Operation Guide

Before Use

Procedure

Cleaning & Care

Care & Notes

Correct tightness

Sleeve condition

Heat protection

Load check

Related Products

Retort Stand

Lab Jack

Need Universal Clamp & Flask Clamp?