Square Key Clamp Three Way Mid Corner for 25 x 25mm Box Section, Galvanised

The square three way mid corner takes two box section rails round a corner upright at 90°, with the upright running straight through, for frames built from 25 x 25mm square box. The upright passes through the square barrel, each rail ends in its own closed square socket, and three grub screws lock all three members. It is the fitting for lower rails and shelf rails at the corners of benches, stands, racks and enclosures, with the square top corner capping the upright above. It suits 25 x 25mm square box section and is malleable cast iron with a galvanised finish for indoor and outdoor use. The price shown is for one fitting, with a minimum order of 5.

Why use a square mid corner

Square frames, no welding. Box section gives a neat, flat-faced frame for benches, stands and shelving. These fittings join it with a hex key, so there is no cutting of mitres, no welding and no grinding.

Rails at any height on the upright. The upright passes through, so the corner can sit wherever a lower rail or shelf is needed, and more than one can be stacked up the same leg.

Square sockets stop twisting. Box section cannot turn in a square socket, so shelves and rails stay level and square to each other once the screws are tight.

Galvanised for indoors and out. The zinc coating protects the iron in workshops, garden centres, markets and yards.

Where it is used

Workbench and table frames, shelving and racking, shop and garden centre display stands, market stall frames, plant benches, cages and enclosures, and any frame built from 25 x 25mm box section where rails meet a corner leg part way up.

Specifications

Which square 25mm fitting goes where

How many do you need?

One at each corner leg for every level of lower rails. A four-legged bench with one lower shelf needs four, plus four top corners. A rack with two lower shelves needs eight.

Choosing the right size

Square key clamps are sized by the outside of the box section. This fitting suits 25 x 25mm box only: measure across one face. It will not grip round tube or 30mm box. For heavier frames, the same corner is made for 40 x 40mm box section, and there is a black 25mm version for indoor frames on show.

Fitting and care

Slide the corner onto the leg at rail height. Cut the rails square to length, deburr the ends and push them fully into the sockets. Square up the corner, level the rails and tighten all three grub screws with a hex key. Check the screws after the first week and once a year. Touch up scratched galvanising with zinc-rich 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.