Grill and gate estimate for fabricators

Measure each section separately, because angle, flat and square each carry their own weight per metre. Add up every piece of 25x25x5 mm angle on the drawing in running feet, every piece of 12 mm square, every piece of flat, and keep the three totals apart.

Turn each total into metres at 0.3048 metres to the foot, then multiply by that section's own weight per metre off the table above. 14 running feet of 25x25x5 mm angle is 4.2672 metres, and 4.2672 x 1.766 kg a metre comes to 7.54 kg. The same sum run on the square and the flat gives their own weight, and the three added together is the steel in the job.

This is a drawing sum, not a scale reading. It tells a fabricator what to expect before anything is cut, and the number this shop finally bills against is what the finished piece weighs on the scale here.

A 4 ft by 3 ft window grill in 25x25x5 mm angle for the border, six uprights of 12 mm square at 3 ft each, and one 25x6 mm flat crossbar running the 4 ft width.

Frame: the border runs 2 x (4 + 3) = 14 running ft, 4.2672 m, x 1.766 kg a metre = 7.54 kg. Uprights: 6 pieces x 3 ft = 18 running ft, 5.4864 m, x 1.130 kg a metre = 6.20 kg. Crossbar: 4 running ft, 1.2192 m, x 1.177 kg a metre = 1.43 kg.

7.54 + 6.20 + 1.43 = 15.17 kg. That is the steel in this grill, off the drawing, before a torch or a saw has touched anything.

This frame's three sections each fit inside one 20 ft length: 14 ft, 18 ft and 4 ft all sit under 20. Bought as three full pieces, the weight is 10.77 + 6.89 + 7.17 = 24.83 kg, against the 15.17 kg the frame itself weighs. The difference is the offcut, a 6 ft drop off the angle, a 2 ft drop off the square, a 16 ft drop off the flat, steel that goes toward the next job rather than this one.

A fabricator cutting to the finished weight instead of buying the full piece still spends a little more than the running-feet sum, because a mitred corner eats a sliver at 45 degrees that a butt joint does not, and the first bite of a fresh cut is never exactly the drawing's own line. No published figure puts a percentage on that margin; it is a workshop's own judgement, built up over the sizes it cuts every week, which is why the number on the scale here is what the bill is finally raised against.

HMB's own sale unit for these sections is the piece, the kilo or the tonne, so both routes, a full 20 ft length or the weight cut close to size, are open on the same call. Which one suits a job usually turns on whether more of the same section is going into the next frame too.

Bring the running feet by section, angle, patti and square kept apart, and say whether the frame is going out in black or galvanised; HMB prints the identical weight per metre either way, so the finish changes the coating and not the sum above.

Say whether you want the full 20 ft length or the weight cut to the finished sizes, and how many frames the same cut list is going into, since that decides what the offcut is worth keeping. We reach all 34 blocks of Saharsa, Supaul and Madhepura in our own vehicles, tempo to tractor to truck, at the market rate for that route, and the section goes on the scale here before it goes on the vehicle. Solar carries the same three shapes off the Alaknanda TMT group's mill; read what Solar and HMB each carry, or bring the drawing straight to the counter.