What should be included in a custom screw RFQ?
A useful custom screw RFQ should identify the controlled drawing or standard, head and drive geometry, complete thread, material, mechanical requirements, finish, critical tolerances, quantity, inspection scope and packing. If the part is based on a sample, the buyer should explain which features must be copied and which requirements still need to be defined.
The goal is not to make the inquiry look technical. The goal is to give each supplier the same information so their quotations can be compared. “Please quote this stainless steel screw” may produce a fast price, but it rarely produces a controlled manufacturing proposal.
This checklist is for OEM buyers, equipment builders, distributors and maintenance teams sourcing custom cold-headed screws, thread-rolled screws, special fasteners and non-standard hardware from China.
Start with one controlling document
The RFQ should say which document defines the part. This may be:
- A buyer drawing with part number and revision.
- An ISO, DIN, ASME or other recognized standard plus stated variations.
- A physical sample supported by measurements and application notes.
- A supplier drawing created from the buyer's sample and approved before tooling.
If confidentiality matters, use the buyer's normal document-control and confidentiality process before sharing proprietary drawings. MAVORIX can coordinate supplier communication, but the buyer should decide which technical files may be released.
Custom screw drawing checklist
| Drawing item | Information to define |
|---|---|
| Part control | Part number, drawing number, revision, units and scale note |
| Overall geometry | Overall length, under-head length, shank, shoulder and point |
| Head | Head style, diameter, height, bearing surface and under-head radius |
| Drive | Recess or drive type, size, depth and applicable gauge requirement |
| Thread | System, nominal diameter, pitch, class or fit, length, lead and start count if non-standard |
| Point or end | Flat, dog, cone, drill, tapping or drawing-specific geometry |
| Material | Exact grade, approved equivalent route and document requirement |
| Mechanical properties | Property class, hardness or other required performance basis |
| Finish | Plating, passivation, coating, color, thickness or corrosion requirement where applicable |
| Tolerances | General tolerance plus clearly identified critical dimensions and geometry |
| Inspection | Gauge, measurement method, sampling or report requirements |
| Packing | Quantity per bag or box, labels, lot separation and export packing |
Define the head and drive as functional features
Head style affects clearance, bearing area and how the screw seats in the assembly. A countersunk screw needs the correct head angle and mating-hole relationship. A flange head changes bearing area. A low head may solve a clearance problem but can affect drive depth and mechanical behavior.
The drive is also more than a visual description. State whether it is Phillips, Pozidriv, hex socket, six-lobe, slot or another form, and define the size or governing standard. For automatic assembly, driver engagement and feeding orientation may need sample testing.
If the original part has a damaged recess, do not use it as the only reference. Send an unused sample or the mating driver specification where possible.
Write the complete thread requirement
“M6 thread” is not always enough. A thread specification may need:
- Metric or inch system.
- Nominal diameter and pitch.
- Coarse, fine or drawing-specific pitch.
- External thread tolerance class or required fit.
- Threaded length and unthreaded shank length.
- Full thread or partial thread.
- Point style and any thread-forming function.
- Left-hand thread, multiple start or other special direction.
- Gauge or inspection requirement.
Thread rolling forms the external thread by displacing material with profiled dies. Our guide to cold heading and thread rolling shows how the headed blank and thread are produced. The manufacturing route still depends on geometry, material, quantity and supplier review.
Material and mechanical requirements are separate decisions
“Steel,” “stainless” and “brass” are material families, not complete specifications. State the required grade or the governing product standard. If alternatives are acceptable, ask the supplier to identify the proposed grade in the quotation instead of approving a silent substitution.
Mechanical property requirements may include a property class, hardness range, tensile or proof requirement, torsional performance or an application-specific test. These requirements do not automatically follow from the material name. For example, carbon and alloy steel fastener property classes are addressed by standards such as ISO 898-1 within its stated scope, but not every custom head geometry or product type is covered in the same way.
Countersunk, low-head and unusual screws deserve careful review because head geometry can affect the applicable test and failure mode. The drawing and purchase specification should state the required basis rather than copying a property class from a different fastener.
Specify the finish for the application
Finish may be needed for corrosion resistance, appearance, electrical behavior, friction control or assembly. Common descriptions include zinc plating, nickel plating, black oxide, passivation and organic coatings, but these terms alone may not define the required result.
Where relevant, state:
- Coating or treatment standard.
- Type and color.
- Thickness range.
- Corrosion-test requirement and acceptance basis.
- Passivation or sealing requirement.
- Thread allowance after coating.
- Appearance limits for visible parts.
- Friction or torque-tension requirement for controlled joints.
- Baking or hydrogen-embrittlement control requirements for susceptible high-strength steel parts.
Tell the supplier the real quantities
Custom screw price depends heavily on tooling and production quantity. Provide more than one number:
| Quantity field | Why suppliers need it |
|---|---|
| Prototype or sample quantity | Helps select machining, soft tooling or production-tool sample route |
| First production order | Establishes the immediate quotation basis |
| Expected annual demand | Helps evaluate cold-heading tooling and repeat-production economics |
| Order frequency | Affects batch planning, material purchasing and inventory discussion |
| Spare or service quantity | Important when the screw supports equipment already in the field |
Separate tooling, samples and production in the quotation
A clear quotation should show:
- Unit price and quantity basis.
- Forming dies, thread-rolling dies and other tooling charges.
- Whether tooling is one-time, reusable and controlled for the buyer's part.
- Sample price and sample lead time.
- Production lead time after approval.
- Included material and finish.
- Inspection reports or certificates included in the price.
- Packing and trade term.
- Tool maintenance or replacement assumptions for repeat orders where relevant.
Approve samples against the drawing revision
The sample stage should answer defined questions. Typical checks include head dimensions, drive fit, overall length, thread gauges, material documents, visible condition, finish, coating thickness where specified and assembly with the mating component.
Record the sample number, drawing revision and approval result. If the buyer accepts a deviation, update the drawing or deviation record before production. Otherwise, the next batch may be made to the original requirement while both sides remember the sample differently.
Application testing remains important. A screw can pass dimensional inspection and still perform poorly in automatic feeding, clamp load, sealing, vibration or a special mating material. The buyer should define and approve tests that depend on the final assembly.
Plan batch inspection before placing the order
Inspection requirements affect production and price, so include them in the RFQ. Depending on risk, the scope may cover:
- Lot identity and quantity.
- Drawing revision.
- Critical dimensions.
- Thread plug or ring gauge results.
- Drive gauge or driver fit.
- Material and mechanical-property documents.
- Finish appearance and coating checks.
- Burrs, cracks, mixed parts and damaged threads.
- Packing count, labels and lot traceability.
A copy-ready custom screw RFQ template
Buyers can use this short structure for the first supplier inquiry:
| RFQ field | Buyer input |
|---|---|
| Part and revision | Part number, drawing number and current revision |
| Product description | Custom screw or fastener application |
| Head and drive | Style, size and governing detail |
| Thread | Diameter, pitch, class, length and point |
| Material | Grade and approved-alternative rule |
| Mechanical requirement | Property class, hardness or test basis |
| Finish | Treatment, thickness, color and corrosion requirement |
| Critical tolerances | List or mark on drawing |
| Quantities | Samples, first batch and annual demand |
| Inspection | Gauges, reports and sampling requirements |
| Packing | Unit count, labels, lot control and export packing |
| Destination | Country and requested trade term |
How MAVORIX supports custom screw sourcing
MAVORIX is a China-side sourcing and coordination partner. We help overseas buyers organize custom fastener RFQs, identify suitable suppliers, compare tooling and production assumptions, follow drawing questions, coordinate samples and collect agreed inspection information. We do not present every workshop or supplier as a MAVORIX-owned factory.
Review our custom cold-headed screw capability page for typical product and process scope. For quotation review, send the drawing, sample photos, material, finish, quantities, application and destination through the contact page.