What information is included in a Bill of Materials?

A BOM typically includes each part or material needed for the job, specs (like dimensions, grade of steel), the quantity required, and sometimes references to drawings or process notes. In steel fabrication, it might also note pre-fabrication processes (for example: cut to length or drill holes) for certain items. Essentially, a BOM includes everything you need to purchase or pull from stock to complete the project.

Why is a BOM important for a small steel fabrication shop?

BOM is important for small steel fabrication shops because it ensures no component is forgotten. Even in a small shop where workers communicate daily, a BOM is the single source of truth for materials. It helps avoid costly delays (waiting on a missing piece of steel) and prevents over-buying. For a small business with tight cash flow, buying exactly what’s needed (and knowing when to reorder) is a big advantage. A good BOM also feeds other processes like quoting (so you cover all material costs) and scheduling (knowing all parts are on hand).

How do we create a Bill of Materials if we’ve only used paper drawings before?

Start by listing all distinct parts from the drawing. Many fabricators do a material takeoff by going through the blueprint and writing down each piece of steel, plate and bolt including sizes and counts. You can do this in a spreadsheet or a simple BOM template. If the project is complex, break it down by sub-assembly. As you transition to digital, you might use steel fabrication software, like EZIIL, to generate and store BOMs for reuse on similar jobs.

Can a small shop manage BOMs in Excel effectively?

Yes, many do. Excel or Google Sheets are common for BOMs. The key is to be consistent and have columns for part numbers or description, quantity, measurement unit, and notes. Double-check entries to avoid typos. For repeated jobs or standard products, you can maintain a master BOM and copy it for new projects. As you grow or handle more complex builds, you might outgrow manual spreadsheets and move to a dedicated BOM management tool, such as EZIIL, that ties BOMs to your other workflows automatically.

What happens if a BOM is inaccurate or missing items?

An incomplete BOM can lead to big issues. Missing items can cause last-minute scrambles. This causes delays and possibly overtime or expedited shipping costs. Additionally, an error could cause over-ordering, tying up money in excess stock. Worst case, you fabricate an assembly and then discover a component is wrong or missing, requiring rework. That’s why it’s worth taking time upfront to get the BOM right and reviewing it before kicking off production

Bill of Materials (BOM) in Custom Steel Fabrication

Bill of Materials (BOM)

What is a Bill of Materials (BOM)?

A Bill of Materials (BOM) is a detailed list of all components, raw materials, and parts (such as pieces of steel, bolts, wires and welds) required to manufacture a product or complete a fabrication project.

A BOM typically specifies item quantites, descriptions, other relevant characteristics (for example material grade or size) and also includes instructions or references for how each item is used.

A clear BOM allows for everyone to know exactly what materials to procure and prep, preventing costly mistakes.

Bill of materials (BOM) example in steel fabrication

Let’s say you’re building a custom staircase. The BOM would list each beam, plate, tread, bolt, and gallon of paint needed.

For example, your Staircase BOM might include:

2 pieces of C-channel (10ft each) for stringers
10 tread plates (12×30 inches)
20 bolts and nuts
1 qt primer

Your BOM guides purchasing to order the right steel shapes and helps the shop floor pull the correct stock from inventory.

If any part is missing from the BOM, the project could stall while someone runs out to get that item. This is why maintaining an accurate BOM is critical.