Preparing a clear request for quotation (RFQ) is one of the most important steps when sourcing custom fasteners. A well-prepared RFQ helps manufacturers understand the required part, evaluate manufacturing feasibility, identify technical risks, and provide a quotation based on defined requirements.
An incomplete request can lead to repeated clarification emails, inconsistent supplier quotations, unexpected tooling costs, delayed samples, or parts that do not fit the intended assembly.
Whether you are sourcing custom screws, bolts, studs, nuts, pins, or other special fasteners, the goal is straightforward: give every supplier the same technical and commercial information, and make it clear which requirements are mandatory.
This guide explains how to prepare an RFQ for custom fasteners, what information to include, which documents to attach, and what questions to ask before approving a quotation.
1. What Is an RFQ for Custom Fasteners?
An RFQ, or Request for Quotation, is a formal inquiry asking a supplier to quote a defined product or manufacturing requirement.
For custom fasteners, an RFQ typically includes:
- A technical drawing, applicable standard, or clearly identified sample reference
- Material and mechanical property requirements
- Thread specifications and dimensional tolerances
- Surface finish and corrosion-resistance requirements
- Order quantities and estimated future demand
- Inspection, testing, and documentation requirements
- Packaging, shipping destination, and requested delivery timing
- Commercial terms and any special project conditions
An RFQ is not simply a request for the lowest unit price. It establishes the basis on which suppliers evaluate the same part and quote comparable scopes of supply.
For custom or non-standard fasteners, a quotation should also identify important assumptions, exclusions, and unresolved technical questions.
2. Start with a Controlled Drawing or Product Reference
The drawing is often the most important document in a custom fastener RFQ because it defines the geometry and acceptance requirements of the part.
What should a custom fastener drawing include?
Where applicable, include:
- Part name, part number, drawing number, and revision
- Units of measurement and sufficient orthographic or sectional views
- Overall length, diameters, head dimensions, shoulders, chamfers, radii, and other functional features
- Thread diameter, pitch, tolerance class, thread length, and end details
- General dimensional tolerances and specific tolerances for critical features
- Material specification and mechanical property requirements
- Heat treatment, surface finish, marking, and other special requirements
- Inspection notes and references to applicable standards
A dimensioned 2D drawing is useful for defining acceptance requirements. A 3D CAD model can help communicate complex geometry, but it should not automatically override the drawing.
If a drawing and CAD model conflict, state which document governs or resolve the discrepancy before requesting a firm quotation.
For geometric dimensioning and tolerancing, buyers may reference the applicable edition of ASME Y14.5 or another agreed drawing standard. The standard provides a framework for interpreting drawing requirements; it does not determine the correct tolerance values for a particular application.
What if you do not have a complete drawing?
You can begin an inquiry with a sketch, photographs, a physical sample, an existing part number, or preliminary dimensions.
However, clearly identify what is known and what remains to be confirmed. A photograph alone rarely defines thread details, critical dimensions, material grade, mechanical properties, or inspection acceptance criteria.
If a sample is used as the starting reference, identify it with a sample number and explain whether the supplier is expected to measure it, prepare a proposed drawing, or quote against an existing specification.
Do not assume that copying the visible shape of a sample establishes every technical requirement.
3. Specify the Fastener Type, Dimensions, and Threads
A product description such as “custom bolt” or “stainless steel screw” is not sufficient to define a complete part.
Identify the fastener geometry
Describe the required type and relevant features, such as:
- Head style and head dimensions
- Drive type or wrenching feature
- Shank diameter and length
- Shoulder diameter and shoulder length
- Threaded and unthreaded sections
- Point style, tip geometry, or end configuration
- Holes, slots, grooves, knurls, or other special features
For special designs, highlight the features that affect assembly, positioning, load transfer, sealing, or tool access.
Define the complete thread requirement
Where applicable, specify:
- Thread system, such as ISO metric or Unified inch threads
- Nominal diameter
- Pitch or threads per inch
- Thread tolerance class or fit
- Thread length and usable thread zone
- Right-hand or left-hand thread, if not standard
- Special thread form, locking, sealing, or thread-forming function
- Whether thread acceptance applies before or after coating
For example, a callout containing only “M8” does not necessarily define every requirement needed for manufacture and inspection. The pitch, tolerance class, and applicable standard may also need to be stated.
For metric threads, refer to the appropriate current edition of the applicable ISO thread standards. If an existing drawing uses an older edition, do not silently change the contractual requirement. Review and approve any proposed revision before implementation.
Practical tip: If thread fit is critical, provide the mating component or its controlled thread specification when appropriate. This can help the supplier evaluate fit and identify missing information.
4. Define Material and Mechanical Properties
Material selection affects strength, corrosion resistance, manufacturing feasibility, service life, and cost. Avoid relying on broad descriptions such as “steel,” “stainless,” or “high strength.”
Information to include
Depending on the application, specify:
- Material standard and grade
- Required mechanical property class or strength grade
- Heat treatment or hardness requirements
- Relevant tensile, proof-load, or other mechanical test requirements
- Required material certificates or traceability records
- Restrictions on substitutions or alternative materials
For example, a carbon steel fastener with a specified property class and a stainless steel fastener with a specified stainless property class are not interchangeable simply because their nominal dimensions are the same.
The material designation and mechanical property requirement should be consistent with the selected product standard, dimensions, manufacturing route, and service conditions.
Explain the operating environment
Include relevant application information, such as:
- Indoor, outdoor, marine, or industrial exposure
- Contact with moisture, salts, chemicals, or cleaning agents
- Operating temperature range
- Static, cyclic, vibration, or other loading conditions
- Contact with dissimilar metals
- Electrical, sealing, or appearance requirements
This information helps the supplier understand the intended application. It does not replace the engineer’s responsibility to approve the material and fastener design.
If the exact material or grade has not yet been finalized, label it as a design decision requiring review rather than allowing each supplier to assume a different specification.
5. Specify Surface Finish and Corrosion Requirements
Surface finish is not merely a cosmetic choice. It can affect corrosion performance, dimensions, thread fit, friction, installation behavior, and compatibility with the mating parts.
Common finish categories include:
- Zinc electroplating
- Hot-dip galvanizing
- Zinc flake coatings
- Black oxide
- Phosphate coatings
- Nickel plating
- Stainless steel passivation
- Other specified coatings or treatments
The appropriate option depends on the base material, required performance, applicable standards, assembly conditions, and environmental exposure.
What should the RFQ state?
Include the following where relevant:
- Exact finish or coating specification
- Applicable standard and edition
- Coating thickness or other measurable requirements, where specified
- Required corrosion test and acceptance criteria, if applicable
- Color, appearance, or restricted-substance requirements
- Thread-fit requirements before or after coating
- Required coating inspection or test documentation
Do not treat a generic term such as “zinc plated” as a complete specification if coating type, thickness, passivation, or other performance requirements matter.
Likewise, a salt-spray test duration should not be interpreted as a guaranteed number of years in service. Laboratory test results and real-world corrosion performance are not directly interchangeable.
If the application involves high-strength steel and a coating process that may introduce hydrogen, define the applicable process controls and verification requirements with the responsible engineer.
For more guidance, see the related article on fastener surface finishes and how to select the right fastener material.
6. Set Dimensional Tolerances and Identify Critical Features
Tolerances determine the permitted variation in a part’s dimensions or geometry. They also influence manufacturing feasibility, inspection requirements, and cost.
A common RFQ problem is specifying unnecessarily tight tolerances on every dimension, while failing to identify the features that actually control assembly performance.
How to specify tolerances effectively
- State the applicable general tolerance standard, if one is used.
- Define specific limits for critical dimensions.
- Use appropriate geometric tolerances when the function requires them.
- Identify important datum references and mating relationships.
- Highlight dimensions that affect fit, location, sealing, strength, or interchangeability.
- State how critical characteristics must be measured or verified when necessary.
Avoid assuming that all suppliers interpret an unspecified tolerance in the same way.
If a dimension is critical to assembly, explain its function where practical. This helps the supplier identify the relevant manufacturing and inspection considerations before finalizing the quotation.
For drawings using GD&T, reference the agreed standard and edition, and make sure the drawing communicates the intended relationship between features.
7. Provide Order Quantities and Demand Information
Quantity is a key commercial input for custom fasteners. It may influence manufacturing route, tooling economics, material purchasing, setup costs, inspection planning, and unit price.
Include more than one quantity when appropriate
Consider providing:
- Prototype or sample quantity
- Initial production quantity
- Expected annual demand
- Potential repeat-order quantity
- Requested price breaks at selected quantities
Ask the supplier to quote the quantities that matter to your purchasing plan. If the supplier recommends different quantity breaks, request the basis for those options.
Do not assume that a higher quantity always produces the lowest total cost. Inventory holding, storage, obsolescence, cash flow, and forecast uncertainty can offset unit-price savings.
Ask about tooling and setup costs
For custom parts, clarify whether the quotation includes any required tooling, fixtures, setup, or engineering work.
Where applicable, ask:
- Is tooling charged separately or included in the unit price?
- Is a separate tooling charge non-recurring?
- Who owns the tooling after payment?
- How is tooling storage, maintenance, or replacement handled?
- Are there quantity-based price breaks?
- Are sample and production costs quoted separately?
The answers depend on the specific project and commercial agreement. They should be confirmed in writing rather than assumed.
8. Define Inspection, Testing, and Documentation Requirements
A quotation should make clear what evidence is required to demonstrate that the supplied fasteners meet the agreed specification.
Not every project requires the same level of inspection or documentation. The appropriate scope depends on product risk, customer requirements, applicable standards, and the intended use.
Common requirements to consider
| Requirement | What to clarify |
|---|---|
| Dimensional inspection | Which dimensions are checked, and how results are reported |
| Thread inspection | Applicable gauges, thread acceptance criteria, and inspection stage |
| Material verification | Required material identification method and evidence |
| Mechanical testing | Required tests, acceptance criteria, and applicable test standard |
| Coating inspection | Required coating characteristics and verification methods |
| Sampling plan | Sample size, acceptance rules, and applicable sampling standard |
| Inspection report | Required format, measured characteristics, and lot identification |
| Material documentation | Certificate type, traceability scope, and delivery timing |
| First-article approval | Whether samples or a formal first-article report are required |
Be precise about the documents you need. For example, requesting a material certificate, a dimensional report, and a mechanical test report may represent three different deliverables.
If you require a particular certificate or inspection report, state that requirement in the RFQ and ask the supplier to confirm whether it can be provided for the quoted scope.
Do not use a generic request for “full inspection” without defining what that means.
9. Explain Sample Approval and Engineering Changes
For a new custom fastener, sample approval can help verify that the proposed part matches the intended design before production release.
Your RFQ should state whether samples are required and what the approval process includes.
Consider specifying:
- Number of samples required
- Sample delivery or review target
- Dimensions and characteristics to be evaluated
- Required test reports or supporting documents
- Who is responsible for approval
- Whether tooling or production may proceed before approval
- How approved samples and revisions will be identified
A sample that appears to fit is not automatically proof that material properties, coating performance, or all critical dimensions comply with the specification.
Control drawing revisions and deviations
Use a controlled drawing revision and a clear process for reviewing proposed changes.
Ask suppliers to identify deviations from the RFQ before they are accepted. Any substitution of material, finish, dimensions, or other controlled requirements should receive the buyer’s approval before implementation.
This is particularly important for repeat orders, where an old sample or email attachment may otherwise be mistaken for the current production requirement.
10. Clarify Packaging, Shipping, and Delivery
Commercial details are part of a usable RFQ because the quoted price and lead time depend on the agreed scope.
Include:
- Required quantity and unit of measure for each item
- Packaging method and protection requirements
- Label content, part number, and revision
- Lot identification or traceability information, where required
- Shipping destination
- Requested delivery date or target schedule
- Whether partial shipments are acceptable
- Requested Incoterms® rule and named place, where applicable
- Any export, customer, or receiving-site requirements
Distinguish manufacturing lead time from transit time. If a target date is important, ask the supplier to identify the assumptions behind the quoted schedule, including sample approval, tooling, material availability, and other relevant dependencies.
A requested delivery date is a target, not confirmation that the supplier can meet it. Obtain written confirmation before committing the schedule to your customer or production plan.
11. Make Supplier Quotations Easy to Compare
When several suppliers receive the same RFQ, compare the complete quoted scope rather than unit price alone.
Use a comparison sheet that covers:
| Comparison item | Questions to ask |
|---|---|
| Technical compliance | Does the quotation meet the drawing and all stated requirements? |
| Exceptions | Are any deviations, exclusions, or assumptions listed? |
| Unit price | Is the price based on the same quantity and specification? |
| Tooling and setup | Are these costs included, separate, or conditional? |
| Samples | Are sample costs and approval requirements stated? |
| Inspection documents | Are all requested reports and certificates included? |
| Lead time | What event starts the clock, and what is the expected completion point? |
| Packaging and freight | Are packaging, shipping, and delivery terms comparable? |
| Payment and validity | Are payment terms, quote validity, and other commercial conditions clear? |
A low quotation may exclude testing, packaging, tooling, or other requirements included in another supplier’s offer.
Ask each supplier to identify open questions and assumptions explicitly. This makes technical and commercial evaluation more reliable.
12. Custom Fastener RFQ Checklist: What to Send
Use this checklist before submitting an inquiry.
Technical information
- Part name, part number, and drawing revision
- Dimensioned drawing and relevant CAD file, if available
- Applicable product standard and edition, where relevant
- Dimensions, units, and critical tolerances
- Thread system, size, pitch, tolerance class, and thread length
- Material specification and mechanical property requirements
- Surface finish, coating, and corrosion requirements
- Application information and mating-part details, where relevant
Quality and approval
- Inspection and testing requirements
- Required material certificates and test reports
- Sampling or acceptance criteria
- Sample quantity and approval process
- Traceability, marking, and lot identification requirements
- Rules for deviations, substitutions, and drawing changes
Commercial and delivery information
- Sample, initial-order, and forecast quantities
- Requested price breaks
- Tooling, setup, and other non-recurring cost requirements
- Packaging and labeling requirements
- Delivery destination and requested schedule
- Shipping terms and any special commercial conditions
- Target quotation date and contact for technical questions
If some information is not yet available, mark it as “to be confirmed.” A visible information gap is easier to resolve than an unstated assumption.
13. Common RFQ Mistakes to Avoid
Sending only a photo or product name
A photo may show the general shape, but it does not reliably define dimensions, thread requirements, material, or mechanical properties.
Better approach: Attach a controlled drawing or clearly identify the information that still needs to be established.
Using vague material descriptions
Terms such as “steel,” “stainless,” and “high tensile” can have several interpretations.
Better approach: Specify the required material standard, grade, property class, and relevant performance requirements.
Leaving the coating specification incomplete
A finish name alone may not define the required coating system or acceptance criteria.
Better approach: State the applicable finish specification, required performance, and thread-fit conditions.
Requesting an unrealistic tolerance without explaining the function
Tight tolerances can affect process feasibility, inspection, and price.
Better approach: Identify functional characteristics and specify the tolerances needed to achieve them.
Asking only for a unit price
A unit price without quantity, tooling, inspection, packaging, or delivery assumptions may not represent the actual purchasing cost.
Better approach: Ask suppliers to quote a clearly defined scope and identify exclusions.
Changing requirements after quotation without revision control
Different suppliers may end up quoting different versions of the same part.
Better approach: Issue controlled revisions and ask suppliers to confirm the version used for their quotation.
14. Frequently Asked Questions About Custom Fastener RFQs
What information is essential for a custom fastener quotation?
At minimum, provide an identifiable product reference, available drawing or dimensions, material and finish requirements, quantity, and delivery destination. A firm quotation may require additional details such as thread tolerances, mechanical properties, inspection scope, and packaging requirements.
Can I request a quote without an engineering drawing?
Yes, you can start with a sample, sketch, photograph, or existing part reference. However, missing dimensions and acceptance requirements may prevent a firm, comparable quotation. Confirm which details must be measured or approved before production.
Should I provide a 2D drawing or a 3D CAD model?
A dimensioned 2D drawing is useful for communicating controlled dimensions and acceptance requirements. A 3D model can supplement it for complex geometry. State which document governs if they conflict.
Do I need to specify the manufacturing process?
Not always. If the process is not a design or contractual requirement, you can define the finished part and ask the supplier to review manufacturing feasibility. If a particular process is mandatory, state it explicitly and explain any relevant requirements.
How can I reduce the cost of custom fasteners?
Start by reviewing unnecessary tight tolerances, simplifying non-functional geometry, providing realistic quantities, and clarifying material and finish requirements. Ask suppliers to identify potential design-for-manufacturing improvements, but require approval before any change to the specified part.
How do I compare quotations from different suppliers?
Check technical compliance first, then compare unit price, tooling, sample costs, inspection documents, packaging, delivery assumptions, and commercial terms. Ask each supplier to list exclusions and deviations so you can compare the same scope.
What should I do if the supplier proposes an alternative material or finish?
Request the technical rationale, relevant supporting evidence, and any impact on performance, dimensions, cost, or compliance. Have the responsible engineering or quality team review the proposal, and approve any deviation in writing before production.
How do I confirm the lead time?
Ask the supplier to define the starting event and the expected completion point. Clarify whether the schedule includes tooling, samples, approval, production, inspection, and transit. Obtain confirmation of the schedule for the specific order.
15. Request a Quote for Your Custom Fastener Project
A complete RFQ helps establish a shared understanding of the part before pricing, sampling, and production planning begin.
If you are sourcing custom screws, bolts, studs, or other special fasteners, prepare the available drawing, material and finish requirements, target quantities, inspection needs, and delivery information.
If some technical details are still under development, identify the open questions so they can be reviewed before the specification is finalized.
Contact HKTL-Fastener to discuss your custom fastener requirements and submit your RFQ for review.
Please include your drawing or sample reference, required quantity, application details, and any special quality or delivery requirements. The quotation scope, feasibility, and schedule should be confirmed against the specific project requirements.
