Two fabricators quote the same drawing and come back 30% apart. Neither is wrong, and neither is necessarily trying it on. They’ve made different assumptions about things the drawing didn’t fully specify.<\/p>\n
Understanding what moves the number is useful in both directions: it tells you which quote is realistic, and it tells you which parts of your own specification are costing money without buying you anything.<\/p>\n
This isn’t a price list. Steel fabrication<\/a> is quoted per job because the variables genuinely differ per job \u2014 a structural steel<\/a> assembly and a custom sheet metal<\/a> part priced by the same shop will be driven by completely different things. But the variables themselves are consistent, and there are eight that matter.<\/p>\n The steel is the foundation of the number, and grade choice moves it more than most buyers expect. Mild and carbon steel sit at the base. Stainless \u2014 SS 304, SS 316 \u2014 is a significant step up, and SS 316 costs meaningfully more than 304 for the molybdenum content that buys you chloride resistance. Alloy steels like EN8D and EN19 carry their own premium.<\/p>\n The form matters alongside the grade. Standard plate thicknesses and common section sizes are readily available; unusual thicknesses may mean either a mill order with a lead time, or cutting down from a larger size with the offcut charged to your job.<\/p>\n Where buyers overspend:<\/strong> specifying SS 316 where 304 is adequate, or a higher grade across an entire assembly when only certain components see the aggressive environment.<\/p>\n Plate thickness determines the cutting process, and the processes have different costs per metre.<\/p>\n CNC plasma cutting is fast and economical across a broad range. Oxyfuel handles heavier sections. As thickness increases, cutting time increases and edge quality changes \u2014 thicker cuts may need edge preparation before welding, which is a second operation.<\/p>\n At E S HAJI & CO, CNC plasma and oxyfuel cutting<\/a> runs to 40mm in-house, which matters for quoting because a job that fits within a fabricator’s own capability doesn’t carry the cost and schedule risk of outsourced cutting.<\/p>\n Where buyers overspend:<\/strong> thickness specified from a standard detail rather than from the actual load case. Every extra millimetre is material cost plus cutting time plus weld volume plus handling weight.<\/p>\n This is the factor most consistently underestimated. Cost tracks total weld length and cross-sectional area, not the number of joints.<\/p>\n A full penetration butt weld on 25mm plate consumes far more consumable, time and inspection than a fillet weld on 8mm \u2014 and may require pre-heat, multiple passes and non-destructive testing. The welding process matters too: MIG, TIG and arc each have different deposition rates and suit different materials and positions. TIG on stainless is slower and more skilled than MIG on mild steel.<\/p>\n Where buyers overspend:<\/strong> full penetration welds specified as a blanket standard where a properly sized fillet would carry the load. Ask your designer which welds genuinely need it.<\/p>\n Tolerance is invisible on a quote and enormous in the shop. A part to \u00b12mm and the same part to \u00b10.2mm are different manufacturing operations \u2014 the tight one may need machining after fabrication, jigs and fixtures, and inspection at multiple stages.<\/p>\n Where buyers overspend:<\/strong> blanket tight tolerances across a whole assembly when only mating faces and bolt holes actually need them. Tolerance the features that matter and open up the rest.<\/p>\n Surface treatment is a distinct cost line. Plain and black oxide are the cheapest. Painting adds preparation, application and cure time. Hot-dip galvanising means the part travels to a galvanising bath, comes back, and gets inspected \u2014 cost plus schedule. Zinc plating, epoxy and PTFE coatings each carry their own process.<\/p>\n Galvanising also has design consequences: vent and drain holes, dimensional growth from the coating, and distortion risk on thin sections. All cheaper to design for at drawing stage than to discover afterwards.<\/p>\n Setup cost is spread across the batch. First-off items carry programming, fixturing, trial and inspection. The second identical item carries almost none of that.<\/p>\n This is why a quantity of fifty is rarely fifty times the price of one \u2014 and why splitting an order across two deliveries of the same part usually costs less than splitting it across two different parts.<\/p>\n Worth noting: because E S HAJI & CO manufactures to order with no minimum order quantity, small quantities are genuinely quotable. They carry a higher per-unit setup share, which is arithmetic rather than a penalty.<\/p>\n A complete drawing gets a tighter quote, because the fabricator isn’t pricing uncertainty.<\/p>\n An incomplete one gets a defensive quote, or a low quote followed by variations. Missing information means assumptions, and assumptions get priced conservatively.<\/p>\n The details most often missing:<\/p>\n Mid-job revisions are the expensive version of the same problem. A change after cutting has started means scrap, rework and schedule disruption \u2014 all of which land back on the price.<\/p>\n Material traceability isn’t free, but it’s cheap relative to what it prevents. A Mill Test Certificate ties a specific batch to its chemistry and mechanical properties. At E S HAJI & CO an MTC is issued with every batch as standard, which means traceability is a given rather than a line item to negotiate.<\/p>\n Additional requirements \u2014 third-party inspection, NDT beyond the standard, welder qualification records, dimensional reports \u2014 are real costs and should be stated up front. Discovering an inspection requirement after fabrication is the worst possible time to price it.<\/p>\n Heavy fabricated assemblies need lifting capacity at both ends and appropriate transport. A 50-tonne handling capability means large single-piece assemblies can be built and moved as one rather than split and site-joined \u2014 usually cheaper overall, but it changes the transport plan. This is a real consideration on heavy steel fabrication<\/a> work.<\/p>\n For export work, proximity to the port affects inland freight and handling. Fabrication in Ambattur, Chennai sits close to Chennai Port, which is a genuine factor on consignments heading to the UAE, Saudi Arabia, Qatar or Oman.<\/p>\n Send the drawing with grade, weld detail, tolerance, finish, quantity and documentation requirements stated. If any of those are genuinely open, say so and ask for options priced separately \u2014 that’s far better than leaving the fabricator to guess.<\/p>\n1. Material grade and form<\/h2>\n
2. Cutting method and thickness<\/h2>\n
3. Weld volume, not weld count<\/h2>\n
4. Tolerance<\/h2>\n
5. Finish<\/h2>\n
6. Quantity and repeatability<\/h2>\n
7. Drawing quality \u2014 the hidden multiplier<\/h2>\n
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8. Documentation and testing<\/h2>\n
Two things that shift the number outside the shop<\/h2>\n
Handling and transport<\/h3>\n
Location relative to port<\/h3>\n
Getting a quote you can rely on<\/h2>\n