Boss Head, Rectangular, Euro

Quick Answer: The Boss Head, Rectangular, Euro is a right-angle connector for laboratory support stands: one slot grips the upright rod of a retort stand and the other grips the rod of a clamp or ring, each tightened by its own thumbscrew. The listing image shows a blue coated rectangular body with two wing-head screws.

How a Rectangular Boss Head Joins Rod to Rod

A boss head, also called a bosshead, clamp holder or double clamp holder, is the small block that makes a retort stand useful. The upright rod on its own cannot hold anything. The boss head clamps onto it at any height, and a second slot at 90 degrees takes the rod of a burette clamp, condenser clamp or retort ring. Loosening one screw lets the assembly slide up or down; loosening the other lets the clamp reach further out or turn on its own rod.

The Euro pattern pictured for this item has a rectangular body with open slots rather than closed holes, so it can be added to a stand that already carries other fittings without dismantling them. The two slots lie on different faces, so the rods cross without touching. The title does not state the metal or the largest rod diameter each slot accepts; boss heads of this type are commonly die-cast and coated, and rod sizes should be matched with your stands. If you would rather avoid a separate connector, the burette clamp with attached boss head has one built in.

When fitting it, turn the rectangular boss head so that the slot holding the clamp rod opens upward. The weight of the clamp then presses the rod into the slot instead of towards the opening, and a screw that works loose does not let the glassware drop.

Specifications

Applications

• Fixing a burette clamp at reading height on a retort stand for acid-base titrations
• Holding a flask clamp and a condenser clamp at two levels on one upright for distillation or reflux
• Mounting a retort ring to carry a separating funnel or a wire gauze over a burner
• Joining two stands with a horizontal cross-bar, for example to hang a pendulum or a spring in physics practicals

Care & Handling

• Tighten each thumbscrew by hand only; pliers can strip the thread or dent a thin-walled rod.
• Wipe acid splashes off the boss head promptly, since a scratched coating lets the metal beneath corrode.
• Keep the load close to the stand and over its base; a heavy flask on a long clamp can tip even a well-tightened stand.

Why Choose LabEquip

Schools and college labs usually need boss heads in larger numbers than stands, because each stand carries two or three fittings. LabEquip lists this Euro pattern with matching clamps in the General Lab Products range; send the quantity and the rod diameter of your stands through the contact page.

Frequently Asked Questions

What is the difference between a boss head and a clamp?

A clamp holds the apparatus itself, such as a burette or flask. A boss head holds nothing by itself; it joins the rod of that clamp to the upright of the retort stand. Most set-ups need one boss head for every clamp or ring that has no connector built in.

Which way up should the boss head be fitted?

Fit it so the slot carrying the clamp rod opens upward. The clamp’s weight then presses the rod into the slot. If the slot opens downward and the screw loosens, the clamp and its glassware can slide straight out.

Can the clamp rod be set at an angle other than 90 degrees?

Not with this rectangular pattern, whose slots are fixed at right angles. To tilt a condenser or tube, turn the clamp on its own rod before tightening, or use a clamp with a swivel joint.

Will it fit my existing retort stands?

It will if your stand rods fall within the range the slots accept. Measure the diameter of both the stand uprights and the clamp rods and give both figures when you enquire, particularly for older or imported stands.

Why does my boss head keep slipping down the stand?

Usually the screw is bearing on a smooth or greasy rod, or the load sits too far from the upright. Clean the rod, tighten the screw firmly by hand and bring the clamp closer in. A second boss head fitted just below the first acts as a stop collar.

Is a boss head needed for a clamp that has its own rod?

Yes, for clamps with a plain rod. The rod has no way to grip the upright by itself, so it goes into one slot of the boss head while the other slot grips the stand.

Last Updated: September 2026