Black Square Key Clamp Internal Connector for 25mm Box Section, Indoor Use

The black square key clamp internal connector joins two square tubes of the same size end to end, fitting inside both for a flush joint. The connector pushes into the ends of the two tubes and is locked with hex socket grub screws, so the joint sits flush with the outside of the tube. It suits 25 x 25mm square box section and is mild steel with a black electrophoretic finish, for indoor use only, so square tube frames can be built without welding. The price shown is for one fitting, with a minimum order of 5.

Why use a square key clamp internal connector

A flush, hidden joint. There is no collar on the outside, so the joint is neat on rails and frames.

No welding. Square box section frames go together with a hex key and can be taken apart, altered or extended later.

A clean, modern look. Square section suits architectural handrails, shop fitting, display frames and furniture where a round tube would look out of place.

A dark, tidy finish. The black electrophoretic coat suits shop fitting, display frames and furniture, and is for indoor use only.

Where it is used

Shop fitting and display stands, office and reception partitions, café and bar frames, garment rails, shelving, tables and furniture, and any indoor frame built from 25 x 25mm box section.

Specifications

Letters refer to the dimension drawing above. Dimensions are for guide only and may vary slightly.

Know its limits

It must not be used as a load bearing joint. It fits 25 x 25mm square box section only; it will not grip round tube or other square sizes. No load rating is published; for a frame that must carry a set load, ask a structural engineer to check the design.

Which 25 x 25mm square fitting?

How many do you need?

One at each joint of this type. Sketch the frame, mark each joint and count the fittings for each type before you order.

Choosing the right size

Square key clamps are sized by the outside of the box section. Measure across the flats of your tube: this fitting suits 25 x 25mm.

Fitting and care

Cut the box section square and deburr the ends. Slide or push the tubes into the fitting, set the frame square and tighten the grub screws firmly with a hex key. Check the screws after the first week and once a year after that. touch up scratches with black paint.

Frequently asked questions

Ordering and delivery

Order 5 or more online, with Express UK Delivery to your site and same-day dispatch on orders before 2pm, Monday to Friday. For a full frame kit, call 01744 520 110 or email sales@industrialsuppliesco.co.uk and we will confirm availability and delivery before you order.