PTFE Fastener RFQ Checklist: Material Identity, Threads and Service Loads

A request for “PTFE screws and nuts” can describe several different constructions. The intended part may be made entirely from PTFE, machined from a filled PTFE compound, coated with a fluoropolymer over metal, or built around a metal insert. Clarifying that construction first helps prevent quotations that look comparable but describe different products.

A useful request for quotation should connect material identity, thread requirements and operating loads. The checklist below provides a practical starting point without assuming that a material name establishes the performance of the completed fastener.

Define the construction in plain language

State whether the fastener body and threads must be polymer throughout, whether fillers are permitted, and whether any metal core or insert is allowed. If a coating is intended, specify the substrate separately from the coating system. Ask the supplier to identify both in the quotation and supporting documentation.

A coated metal bolt needs its own substrate, coating and finished-part specification.

For a solid polymer part, request the resin or compound designation, filler type and content where applicable, and the permitted use of reprocessed material. Require traceability to the material used for the supplied batch. Color and a commercial product name are insufficient identifiers on their own.

Treat filled and unfilled materials separately

PTFE compounds can be formulated to change mechanical behavior. The effects on compression resistance, wear and creep depend on the formulation.

Ask for data for the proposed grade and its test conditions. If chemical cleanliness, electrical insulation or contact with a specific medium is important, make those requirements explicit. Review the entire formulation and construction against them. Do not transfer a property value from an unfilled resin sheet to a filled fastener or a coated assembly without supporting evidence.

Specify the complete thread requirement

Include the thread system, nominal size, pitch or threads per inch, tolerance class, thread direction and required engagement. State whether the thread extends over the full shank or only part of it. For a nut, identify the required usable threaded length and the mating component.

Relevant references include ASME’s B1 screw-thread standards: B1.1 covers Unified inch threads and B1.13M covers metric M-profile threads. The applicable reference and edition should be agreed in the specification. A thread designation does not establish the load rating of a polymer fastener.

Identify critical dimensions such as head geometry, overall length, bearing face and tool engagement. Agree on the inspection method and conditioning or measurement temperature for the polymer part. For coated threads, state whether dimensional acceptance applies before or after coating and how finished fit will be verified.

Describe the loads and the assembly method

Sustained loading deserves particular attention because PTFE can deform with time. Ask the designer to define the required clamp load, load direction, duration, temperature and acceptable movement. Include vibration, repeated assembly and any external bending or shear that the joint must withstand.

Then provide the assembly details:

• Mating-part material and internal-thread specification.
• Available engagement length and the bearing area under the head or nut.
• Washer arrangement and any lubrication or surface treatment.
• Installation tool, proposed tightening method and access limitations.
• Whether the fastener will be reused and how serviceability will be checked.

Request an installation procedure supported by the proposed part and joint. Avoid borrowing a torque value from a steel-fastener chart or another polymer grade. If clamp-load retention is important, define a representative assembled-joint test that measures it after the relevant dwell and thermal exposure.

Make quotation acceptance measurable

A concise RFQ package should contain a controlled drawing, material and construction requirements, service conditions, inspection requirements and sample-approval criteria. Ask suppliers to identify deviations explicitly rather than leaving them inside a general description.

Before production approval, confirm material identity, dimensional results, mating fit and the agreed functional tests. A short-term strength result alone may leave long-duration deformation unanswered. Keep acceptance criteria aligned with the actual duty and have the responsible engineer approve safety-critical applications.

The IKSONIC PTFE fastener page is a relevant starting point for product discussions. When you submit an RFQ, state the intended construction clearly and request confirmation of the specific material, tolerances and evidence proposed.