SHANGERS / BUYER GUIDE
Quote the finished part, not just the outline.
A flat outline tells a supplier where material begins and ends. It does not necessarily tell them how a bracket must fit after forming. Before asking for a price, describe the assembled condition and identify the few dimensions that decide whether the part works. The goal is not a crowded drawing. It is a drawing that leaves fewer important assumptions to the reader.
1. Start with the mating component
For a U-shaped bracket, ask what belongs between the legs. Is the internal opening a clearance space, a locating feature or part of a fastening arrangement? State where that opening is measured. For an angle bracket, identify which face rests against the assembly. An assembly sketch can explain this more clearly than another general note saying 'high precision'.
2. Distinguish inside and outside dimensions
An overall width and an internal gap are not interchangeable. Material thickness and bend geometry sit between them. Likewise, leg length can be measured to an outside corner, an inside surface or another reference. Use the drawing's chosen references consistently. If a supplied sample is your starting point, say which dimensions were measured and which still need to be agreed.
3. Describe holes in the formed condition
Show how the hole relates to the surface that locates the bracket. If two holes must accept one fastener, communicate that assembly relationship. Features near a bend require attention: Protolabs' bend-radius guidance explains that deformation near a bend can affect nearby holes. Its published limits describe its own service, so do not copy a numeric rule into every supplier's drawing without a feasibility review.
4. Include the material condition, not just the family
'Steel' may be enough for an early conversation, but it is not a final purchase specification. Give the grade, thickness and relevant condition when known. If you want the manufacturer to recommend a route, provide the environment, assembly needs and acceptable alternatives. Do not let an unconfirmed material assumption become an unnoticed difference between two quotations.
5. Make finishing and edge requirements visible
Identify faces that will be seen, surfaces that mate and edges that will be handled. State the requested coating or treatment and any areas that must remain untreated. Ask whether the fit-critical dimensions are evaluated before or after the specified finish. A photograph of a shiny bracket does not define a plating system, coating thickness or cosmetic acceptance standard.
6. Agree what makes a sample acceptable
Separate dimensional inspection from assembly approval. A sample may meet the listed dimensions yet reveal an omitted assembly requirement. If a mating component or fixture will be used, agree how that check is performed. Define any load or functional test with the responsible engineer; do not substitute a generic load claim for an actual requirement.
7. Send quantity and packing information together
State the initial sample quantity, expected order quantity and whether the design is likely to change. Also describe how parts will be handled on arrival. Open legs and thin tabs can require separation or orientation control. Ask the quotation to distinguish tooling, parts, finishing and any special inspection or packing rather than comparing only an unexplained unit price.
A useful final question
Before sending the RFQ, ask: could another person identify the surfaces that control fit without talking to me? If not, add a marked assembly view. That small addition is often more useful than repeating broad requests for premium quality, fast delivery or tight tolerances. A manufacturing review can then address the actual part instead of first reconstructing its purpose.
Technical reference: Protolabs: Sheet Metal Bend Radius Guidelines. Referenced product specifications are examples, not SHANGERS product ratings.
