How Do You Write an RFQ for Custom Rod Ends, Bearings, Bushings and Linkage Parts?

Why does a complete request matter?

Because a quote is only as good as the request. An estimator who lacks the material grade, thread class or paperwork has three options. They can quote on assumptions, which come back later as clarification emails, changed prices and parts that fail inspection. They can pad the price to cover what they do not know. Or they can stop and send you a list of questions, and your purchase slips while you answer.

The cost of a vague request is rarely the first quote. It is the second one, after the supplier reads the print.

What does every RFQ need, whatever the part?

Eight things.

1. The part. A drawing with its revision printed on it, or a part number plus the key sizes. An out-of-date revision is the most common silent error: if the print says Rev B and your plant runs Rev D, you buy the wrong part at a competitive price. Send a 2D drawing and, where you have one, a 3D model that carries the same revision.
2. The standard, with its revision. "Metric rod end" fits many parts. Name the standard you build to, and its year or revision letter, if there is one.
3. The material, and its grade. A material called only "stainless" leaves the grade open. Name the grade (for example 304-type or 316-type, A2 or A4), or the alloy and condition for steel, and allow substitutes only when you approve them.
4. The finish, and the stage it applies to. Name the process (zinc plating, black oxide, anodising, a coating) and, where it matters, the thickness. State whether a dimension applies before or after finishing. A plating of a few micrometres changes a thread fit or a bore. Settle this in the request, not on the shop floor.
5. Tolerances that matter. Say which features carry tight tolerances and which are general. Do not leave it to interpretation; tight tolerances raise cost, so ask for them only where function needs them.
6. The load and the duty. How the part is loaded (pushing, pulling, sideways, a mix), how large the load is and whether it is a working figure or a limit, how fast and how far it moves, the temperature, and the environment (wet, dust, chemicals). A supplier can confirm a choice against a real load and cannot do it against a catalogue figure. For a vehicle or off-road link, also say where it sits (steering, a suspension locating link, a shifter or throttle linkage), the angle it must tilt through at full travel, the worst event you expect (a landing, a strike), and any vehicle-maker or series requirement it must meet; the supplier cannot assume these. See off-road rod ends for typical vehicle uses.
7. Quantity. The order quantity now, and the annual use. Volume drives price, and without annual usage a supplier has no basis for a volume price or a stocking plan. Say whether this is a prototype or a repeat buy.
8. Documents, packaging and delivery. The certificates and reports you need, how the parts are packed and marked, the delivery date and the delivery terms (the Incoterm, such as Ex Works or Delivered Duty Paid).

A ninth line is cheap and useful: what happens if the part fails. A part that holds up a guard and a part that holds up a load are not the same risk, and the supplier can build in margin only if told.

What does each type of part add?

The eight items above fit every part. Each type has its own few fields that, if missing, are the usual reasons for a clarification email.

The choice comes down to three routes: a standard part, a modified standard (an adjusted thread, material, finish or liner on a proven design) and a full custom design. Say which you expect. If a standard part nearly works, a modification is usually the shorter path, and saying so helps the supplier answer the right question.

What do the documents prove, and what do they cost?

Paperwork is priced into the quote. Lab testing and document control cost money, and testing or paperwork that was never priced into the quote will not arrive with the parts. So ask for what you will actually use, and say so in the request. The documents are not interchangeable.

• Material test report (mill certificate). Issued by the mill, it shows the heat or lot number, the material specification, the chemistry, the mechanical test results and the country of melt. The heat or lot number identifies one batch of metal.
• The type of certificate matters. Material certificates come in types, defined in the EN 10204 standard, and they differ in whether the results belong to your own batch and who confirmed them. Name the certificate type you need in the RFQ and take its exact meaning from the standard itself or from your supplier in writing, not from a summary.
• Certificate of conformance. A statement by the supplier that the part meets the specification. A distributor's certificate may include no test values at all, so it proves a promise, not a measurement.
• Dimensional report. Measured values of named features on a stated number of parts. It proves those features on those parts, and only the ones you asked to be measured.
• First article inspection. A full check of the first parts against the drawing, to confirm the process before the run.
• Traceability. The link from the finished part back to a heat or lot. Check that the number on the paper matches the number on the metal, and ask what the supplier does with material left over after a job, because that is where traceability usually breaks.

A useful rule: a document proves only what was measured, on the parts that were measured. If you need proof of a load rating, of a coating's salt-spray life or of hardness, name the test and the sample size in the RFQ.

What if you only have a worn part and no drawing?

Send what you have. Usable starting points are a worn or broken sample, a partial or legacy drawing, the mating components, and the application requirements. The reverse-engineering process is the same everywhere: measure the part, make a drawing or model, choose the material, machine it, inspect it.

You can help by recording four things.

1. What the part does. Where it fits, what it connects to, which way it is loaded, and what made it fail. The wear pattern shows the load direction.
2. Measurements from the unworn features. A worn bore is no longer its original size. Measure the mating pin or stud, which tells you the nominal size, and measure threads, the body width and the overall length where they are still intact. Photograph the part from each side with a scale in the picture.
3. The mating parts. Send the pin, the bracket or a drawing of the housing if you can. The fit with them is part of the specification.
4. The material, if known. It cannot be told by eye. A hardness check or a lab analysis gives a grade; if you do not have one, say so, and ask the supplier to recommend one for the duty. A reverse-engineering shop may also suggest a material upgrade, so say whether you want a like-for-like copy or a better material.

Ask for an approval drawing before production. A drawing you have signed is the basis for acceptance and for the next reorder.

A one-page checklist

How do you send the request?

Send it with a drawing, a sample or photos of the old part. SYZ builds rod ends and related parts to customer drawings, so the drawing and the checklist above are what a quotation is built from.

FAQ