Zinc Plated Strap Bracket Flat And Pressed G-JM14

The G-JM14 Strap Bracket, Flat And Pressed

One strip, two products. The same yellow zinc plated steel is supplied flat or pressed into an L, and which one a buyer wants depends on the joint rather than on preference: a flat plate joins two surfaces that are already in line, while a pressed bracket holds two surfaces at a right angle. Keeping both in one range means a workshop can order one line item and get the plate and the bracket it needs from the same strip, same finish, same screw size.

The finish is yellow zinc, which is a chromate over electroplated zinc rather than a paint. It is the standard finish for this class of hardware because it protects the steel in a dry interior, it takes a screw head without flaking, and it costs less than stainless. The colour varies from part to part, from pale gold to olive, and that variation is a property of the process rather than a defect: a carton of yellow zinc brackets will not be one colour.

The Two Forms

The flat plate is the simpler part and the more useful one on a repair: it lies over a split panel, spans a joint, or backs up a butt where a bracket cannot reach. Five holes along 71 mm give enough fixings to pull a joint closed, and the plate can be cut or bent on site if the job needs something shorter.

Why The Angle Is Pressed Rather Than Welded

A pressed bracket is folded from one piece of strip, so there is no weld to fail and no second operation to pay for. The fold also stiffens the part: an L section is many times stiffer than the same strip laid flat, which is why a 1.4 mm pressed bracket will hold a corner that a 1.4 mm flat plate would sag under. The trade is that the fold is the weak point of the part, and it has to be radiused rather than creased sharp, or the steel will crack along the outside of the bend.

That is also why the pressed brackets in this range carry their holes well away from the fold. A hole close to a bend takes material out of the very section that carries the load, and on a bracket this thin a hole in the wrong place turns a stiff corner into a hinge. Look at the pressed bracket in the frames and the nearest hole sits a clear distance up the leg.

Hole Sizes And What Fits Them

The large holes in this range are sized for a screw that will carry the joint rather than locate it: the figures printed on the drawing are 7 mm and 12 mm, with 16 mm and 19 mm spacing between centres on the parts that carry a pair. A 7 mm hole takes a screw just under the hole size, which is what a timber joint that has to stay tight is fixed with. A 12 mm hole is a clearance hole for a larger fixing or for a bolt, and it lets the bracket be adjusted before the fixing is tightened, which matters when the bracket is holding a frame rather than a panel.

Where a hole is larger than the screw, use a washer. On a 1.4 mm strip a screw head alone will dish the steel round the hole and the joint will loosen as the plate springs back. A washer spreads the load and costs almost nothing, and it is the difference between a repair that holds and one that is re-done in a month.

What These Are Called

The flat form comes in on enquiries as a flat plate bracket, and it is the phrase used when the buyer wants a plate rather than an angle. The pressed form comes in as a pressed steel angle bracket, or by its size as a 40 x 40 angle bracket, which is the way a merchant lists the part on a shelf. Both phrases point at the two forms in these frames and neither is a translation of the other.

What a drawing will not tell you is which form is wanted. Ask what the joint looks like: two panels in the same plane take the plate, two panels meeting at a corner take the pressed bracket, and a joint that has to do both takes one of each.

Cutting And Drilling On Site

Both forms are 1.4 to 1.6 mm strip, which cuts with a hacksaw and drills with a step drill or a sharp twist bit at low speed. The trap is heat: yellow zinc will burn off at the cut edge if the part is ground hard, and a burnt edge is the first place rust starts. Cut slowly, touch up the raw edge with a zinc-rich paint, and the plate will outlast the joint it is holding.

When a hole has to be added on site, drill from the face that will be against the timber, so any burr ends up on the outside where it can be filed off. A burr left between the bracket and the panel stops the bracket seating, and a bracket that does not seat will rock no matter how tight the screws are.

Checks On Delivery

Four checks. Finish: a continuous yellow chromate with no bare grey patches, since a bare patch is where rust begins. Fold: a pressed bracket should sit flat on its two legs with no rock, which is the quickest test of whether the fold is square. Holes: no burr on the face that will sit against the panel. Count: the flat plates and the pressed brackets are different parts and have to be counted separately, because a carton that has been mixed at packing cannot be sorted by eye.

State the form, the size and the hole when ordering. On this range that is enough to identify the part, because the strip is constant and the forms are few.

Two Bracket Joints, Step By Step

A bracket joint that fails usually fails for a reason the fitter can see before the first screw goes in. Set the bracket on the corner dry, with no screws, and look along both legs: a pressed bracket that rocks is either folded off square or sitting on a high spot, and no amount of tightening will pull it down. File the high spot, or knock the fold straight on a block, and try the bracket again before driving anything.

When the bracket sits flat, mark through the holes with a bradawl rather than a pencil. A pencil mark on a dark zinc surface is hard to see and the drill wanders; a bradawl leaves a cone that catches the point. Drill the pilot, offer the bracket back up, and put the screw nearest the fold in first. That screw is the one that decides whether the bracket pulls the joint square, and the bracket will move as it tightens, so leave the far screw loose until the first one is home.

The flat plate is the same sequence with one difference: it has no fold to set the angle, so the joint has to be held while the first screw goes in. Clamp it, or put one screw in at each end of the plate and check the joint before filling the holes between them. A plate that is used to pull a split closed will close the split at the ends and leave it open in the middle unless the plate is pulled down in stages, working from the centre outwards.

What A Pressed Bracket Will Not Do

A pressed bracket holds an angle, not a load. It is a connector, and the load path through it is the two screws and the timber around them, not the bracket itself. Where a bracket is asked to carry weight, as on a shelf or a step, the bracket has to be sized for that load and fixed with screws long enough to reach sound timber; a thin pressed bracket on short screws will pull out before it bends. That is a fixing problem rather than a bracket problem, and it is worth saying so before a customer replaces a bracket that was never the weak point.

Where the bracket is expected to carry load, specify the plate instead and span the joint: a flat plate on the hidden face, screwed through into both members, behaves like a strap and is far stronger than a pressed bracket of the same strip. The bracket is quicker to fit; the plate carries more. Both are in this range for that reason.

Three Questions A Bracket Order Usually Asks

Which bracket? The bracket that matches the joint, not the bracket that is cheapest: a flat plate for a butt, a pressed bracket for a corner. How many brackets? Count the corners and add a bracket for each repair that has already failed once. What fixing? A fixing long enough for the bracket to reach timber, because a bracket is only as good as what it is screwed to. Answer those three about any bracket in this range and the part is specified.

Where Each Form Earns Its Place

• A split in a drawer side, where a flat plate spans the damage and pulls it closed.
• Two panels meeting at a corner, where a pressed bracket holds the angle.
• A butt joint in a frame, where the plate backs the joint on the hidden face.
• A shelf that has dropped at one end, where the pressed bracket re-hangs the corner.
• A repair on a bed frame rail, where a plate is used because a bracket will not fit.
• Cabinet carcasses assembled on site, where pressed brackets are quicker than a timber block.
• Packing cases and exhibition crates, where a flat plate is the cheapest way to join two boards.
• A joint that has been repaired once already, where a longer plate reaches sound material either side.

Why Yellow Zinc And Not Bright Zinc

Bright zinc is the silvery finish and yellow zinc is the chromate version of the same plating. The yellow chromate gives noticeably better protection in a damp interior and it resists fingerprinting, which is why it is the finish used on hardware that is handled before it is fitted. Neither finish is for outdoor exposure, and neither will survive a wet wall; where the bracket will see water, the part to specify is stainless.

The colour variation between parts is worth explaining to a customer before it is queried. A carton of yellow zinc brackets can range from pale gold to olive green, and a buyer who expects one colour will read the variation as a mixing error. It is not: the chromate bath and the part geometry between them decide the shade, and the protection is the same across the range.

The G-JM14 range is a yellow zinc plated steel strap bracket in two forms from the same strip: flat at 71 mm by 18.5 mm in 1.6 mm material, and pressed into an angle with 40 mm legs, 18 mm wide, in 1.4 mm material. Hole spacing and diameters follow the issued drawing.

Say which form the joint needs and what fixing will be used, and the plate or the bracket can be checked against the job before anything ships. Mixed cartons can be packed by form and by count.