Why Three Quotes for the Same Heavy Frame Come Back 40 Percent Apart

Three shops quote the same drawing and the prices come back 5,400 dollars, 6,900 dollars and 9,200 dollars. The buyer’s first instinct is to assume the low quote is either the best deal or a shop about to cut corners. Usually neither is true. The quotes differ because each shop silently filled a gap on the drawing with its own assumption, and the assumptions were not the same.

This guide walks through where those gaps usually sit, so a buyer can close them before quoting rather than after, when the answer is a change order. The RFQ spec template is built to prevent exactly this problem; this article explains why it matters.

The drawing says less than it looks like it says

A drawing communicates geometry precisely and process almost never. Material grade, weld standard, NDT extent, machining tolerance, surface finish and packaging are either called out explicitly or they are not, and where they are not, every shop fills the gap with whatever it does by default. Two shops with different defaults produce two different prices for the same geometry, and neither shop has done anything wrong.

Where the gaps usually are

Material certificate level. A grade without a certificate level defaults, in different shops, to a mill test report, an EN 10204 2.2 or a 3.1 certificate. The 3.1 certificate, witnessed by an independent party, costs more and takes longer to obtain. A quote assuming 2.2 and a quote assuming 3.1 for the same “S355” callout are pricing different things.

NDT extent. “Weld per AWS D1.1” says nothing about how much of the weld gets inspected. One shop prices visual inspection only, because the standard’s default extent for the joint category may not require more. Another prices 100 percent UT because that is its standard practice for anything called heavy fabrication. The NDT guide explains what each method costs and what it is actually checking for.

Stress relief. A drawing that specifies a flatness tolerance without saying whether it is machined before or after thermal stress relief leaves the shop to guess. A shop that assumes no relief is required prices less and delivers a part that may not hold the tolerance once it is machined; a shop that assumes relief is required prices for a furnace cycle the drawing never actually asked for. Either way the quotes are not comparable. Our stress relief guide covers when it is genuinely needed.

Machining setup. A part with several machined faces can be finished in one setup on a large enough machine, or in several setups on a smaller one, and the second approach costs more in labor and produces worse relative accuracy between features. A drawing with a coplanarity or perpendicularity call-out between two faces is implicitly asking for one setup, whether it says so or not, and a shop without the machine for that will either quote a multi-setup approach (cheaper, riskier) or decline the job.

Packaging and freight. “Export packing” means a wooden crate to one shop and a VCI-wrapped, desiccant-loaded crate on a steel skid to another. For a part that will sit in a container for six weeks, the difference matters, and it is invisible in most quotes until the packing line item is broken out.

Incoterm and what it actually includes. An EXW quote and a FOB quote for the same part are not the same number with freight added; FOB usually includes local transport, export customs clearance and loading, and different shops price those differently depending on who they use. The Incoterms guide breaks down what changes hands at each point.

How to close the gap before quoting

The fix is not to interrogate every shop after the quotes arrive. It is to specify the six items above on the RFQ itself, so every shop prices the same scope:

1. Material grade and certificate level (2.2 or 3.1).
2. NDT method and extent, by weld category if it varies across the part.
3. Whether stress relief is required and, if so, before or after machining.
4. Which faces are machined in a common setup, with the tolerance that requires it.
5. Packaging: crate type, VCI, desiccant, if the shipment is long or maritime.
6. Incoterm, named clearly, not just “FOB” without a named port.

A drawing with those six items answered gets quotes that differ because of price, lead time and shop quality, which is the comparison a buyer actually wants to make. A drawing without them gets quotes that differ because of six separate silent guesses, and the lowest number usually means the shop guessed the least, not that it works the cheapest.

Getting a comparable set of quotes

We build the RFQ spec with you before it goes to shops, specifically to close these gaps, and we send it to up to three shops so the quotes that come back are actually the same scope. Send your drawing through the RFQ form and we reply within 24 business hours.