# Thread-forming screws

Receiving-thread formation, lobular and lead geometry, material conditions, and bounded TAPTITE 2000 examples.

Reviewed: 2026-10-31

Tags: components, fasteners, screws

The TAPTITE 2000 brochure's **MR4 × 0.7** medium-light steel-member entry gives **1.4–2.4 mm** thickness, **3.64 mm** pilot hole and **#27 / 3.66 mm** drill designation. The drill size is a separate catalog field from the pilot value. Keep the recommendation with that thread form, host and thickness. Check the actual hole and forming torque for the assembly. [TAPTITE 2000 brochure, PDF page 5](https://www.duo-taptite.com/assets/files/TAPTITE-2000-REMINC-CONTI-VERSION-SP-Table-Corrected-10-16-19.pdf#page=5).

A forming screw displaces receiving material into a mating thread. [TAPTITE 2000 end-user specification PR-180, PDF page 2](https://www.duo-taptite.com/assets/files/TAPTITE-2000-Engineering-Guidlines.pdf#page=2), [TAPTITE 2000 brochure, PDF page 4](https://www.duo-taptite.com/assets/files/TAPTITE-2000-REMINC-CONTI-VERSION-SP-Table-Corrected-10-16-19.pdf#page=4).

The examples use an existing receiving hole. Check pilot size, axial engagement and forming torque for the actual host. [TAPTITE 2000 brochure, PDF pages 4–5](https://www.duo-taptite.com/assets/files/TAPTITE-2000-REMINC-CONTI-VERSION-SP-Table-Corrected-10-16-19.pdf#page=4), [PR-180, PDF pages 7–9 and 14](https://www.duo-taptite.com/assets/files/TAPTITE-2000-Engineering-Guidlines.pdf#page=7).

## Lobular body, thread profile, and lead

TAPTITE 2000 combines a TRILOBULAR cross-section with the proprietary Radius Profile thread form. These describe different geometry: lobulation is the departure from a round cross-section, whereas the profile describes the thread tooth. The brochure further distinguishes greater out-of-round geometry in the forming-point region from reduced lobulation on the thread body. A thread-forming screw is therefore not defined by nominal diameter and pitch alone. [TAPTITE 2000 brochure, PDF pages 2–3](https://www.duo-taptite.com/assets/files/TAPTITE-2000-REMINC-CONTI-VERSION-SP-Table-Corrected-10-16-19.pdf#page=2)

The **May 2019 revision of PR-180** specifies a four-thread tapered lead for standard TAPTITE 2000 sizes M5 and smaller. For M6 and larger it describes two stabilizing threads, a three-thread tapered lead, and dual TRILOBULAR geometry. Its introduction separately identifies the short-point SP variant for blind holes in aluminum, zinc, and magnesium and the CA variant as a hole-finding point. These are named configurations, not interchangeable meanings of “lead.” [PR-180, PDF pages 2 and 4](https://www.duo-taptite.com/assets/files/TAPTITE-2000-Engineering-Guidlines.pdf#page=2)

For an exact dimensional example, the PR-180 **MR6, pitch 1.00 mm** body row gives **C = 5.90–6.03 mm** and **D = 5.78–5.93 mm**. C and D are the body's cross-section dimensions identified in that drawing, not receiving-hole diameters. The page expressly states that dimensions are before plating; it separately identifies ordered screw length Ls. These values do not specify a coating allowance, stock length, or current drawing for an individual supplied part. [PR-180, PDF page 4](https://www.duo-taptite.com/assets/files/TAPTITE-2000-Engineering-Guidlines.pdf#page=4)

## Receiving material and heat treatment

PR-180 separates three heat-treatment routes rather than assigning one condition to all TAPTITE 2000 screws. Its standard small-size steel configuration is case hardened; CORFLEX-I uses neutral hardening with a selectively induction-hardened forming point; CORFLEX-N is neutral, or through, hardened for soft metals such as aluminum, zinc, and magnesium. The screw's forming region and its load-carrying body can consequently have different treatment functions. [PR-180, PDF pages 2, 7, 10 and 14](https://www.duo-taptite.com/assets/files/TAPTITE-2000-Engineering-Guidlines.pdf#page=2)

The case-hardened and CORFLEX-I sections each state an intended receiving-steel scope of **up to 250 HV**. That scope limit is not the hardness of their test plate, nor does it establish suitability for every steel at that hardness. The case-hardened forming-test description instead uses low-carbon steel at **115–150 HV30**. The CORFLEX-N test description uses an aluminum plate at **HB 30–75**. The different scales and material descriptions belong to their respective test contexts. [PR-180, PDF pages 7, 9, 10 and 16](https://www.duo-taptite.com/assets/files/TAPTITE-2000-Engineering-Guidlines.pdf#page=7)

The case-hardened section describes carburizing or carbonitriding, quenching, and tempering. Surface condition is a separate variable: the brochure's torque data use zinc-plated, waxed screws, while PR-180 allows lubricant in its case-hardened thread-forming capability test. Neither a heat-treatment name nor a nominal strength designation alone reproduces those friction and forming conditions. [PR-180, PDF pages 7–8](https://www.duo-taptite.com/assets/files/TAPTITE-2000-Engineering-Guidlines.pdf#page=7), [TAPTITE 2000 brochure, PDF page 10](https://www.duo-taptite.com/assets/files/TAPTITE-2000-REMINC-CONTI-VERSION-SP-Table-Corrected-10-16-19.pdf#page=10)

## Pilot diameter, drill designation, and engagement

The brochure uses percentage thread engagement as a radial thread-profile measure. Its **MR5 × 0.8** example associates a **4.58 mm** pilot hole with **80%** engagement. It explicitly says its hole-versus-percentage relationship is linear and becomes less accurate below **70%** engagement. Those percentages are the source's geometric approximation, not percentages of joint strength or screw length. [TAPTITE 2000 brochure, PDF page 4](https://www.duo-taptite.com/assets/files/TAPTITE-2000-REMINC-CONTI-VERSION-SP-Table-Corrected-10-16-19.pdf#page=4)

Axial engagement is a separate quantity. The next table groups steel-member thickness relative to nominal screw diameter under its own “application duty class” headings. Thus a radial percentage, a member thickness, and the length occupied by full-form versus lead threads describe different aspects of engagement. A single percentage does not establish the full load-bearing length in a blind or through hole. [TAPTITE 2000 brochure, PDF pages 3–5](https://www.duo-taptite.com/assets/files/TAPTITE-2000-REMINC-CONTI-VERSION-SP-Table-Corrected-10-16-19.pdf#page=3), [PR-180 lead drawing, PDF page 4](https://www.duo-taptite.com/assets/files/TAPTITE-2000-Engineering-Guidlines.pdf#page=4)

Pilot diameter and drill designation also differ. In the brochure's **MR4 × 0.7, medium-light steel-member** entry, the thickness range is **1.4–2.4 mm**, the pilot-hole value is **3.64 mm**, and the listed drill is **#27 / 3.66 mm**. The adjacent values illustrate why a nominal tool designation is not itself a measured-hole tolerance. This is a bounded catalogue entry, not a universal pilot-hole recommendation for an M4 screw. [TAPTITE 2000 brochure, PDF page 5](https://www.duo-taptite.com/assets/files/TAPTITE-2000-REMINC-CONTI-VERSION-SP-Table-Corrected-10-16-19.pdf#page=5)

## Forming, tightening, removal, and failure torque

The brochure's torque table treats thread-forming torque, first-removal prevailing torque, recommended assembly torque, and failure torque as separate results. One selected row is reproduced below to make those distinctions concrete. **Every torque value is in N·m**; the dimensions are in millimetres. [TAPTITE 2000 brochure, PDF page 10](https://www.duo-taptite.com/assets/files/TAPTITE-2000-REMINC-CONTI-VERSION-SP-Table-Corrected-10-16-19.pdf#page=10)

| Exact source row | Plate thickness | Hole | Nearest drill | Forming torque | First-removal prevailing torque | Source's recommended assembly torque | Failure torque |
| --- | --- | --- | --- | --- | --- | --- | --- |
| TAPTITE 2000 MR4 × 0.7 | 2.0 | 3.64 | #27 | 0.55–0.75 | 0.25–0.35 | 1.80 | 3.10–4.2, marked * |

The stated laboratory conditions are **hex-flange heads, zinc plating plus wax, low-speed driving, cold-rolled steel test plates, and plain flat steel washers under the heads to absorb tightening**. The row's asterisk indicates probable nut-thread stripping; the table uses a different mark for probable screw breakage. The first-removal value concerns rotation after the head has been unseated. It is not the head breakaway torque, the forming torque, or a guarantee of repeated use. [TAPTITE 2000 brochure, PDF page 10 and notes](https://www.duo-taptite.com/assets/files/TAPTITE-2000-REMINC-CONTI-VERSION-SP-Table-Corrected-10-16-19.pdf#page=10)

PR-180 describes a different kind of evidence in its case-hardened thread-forming capability test: formation of a full-major-diameter internal thread through the plate, no screw-thread deformation, and a formed thread capable of accepting a standard 6g machine screw. Its stated driving-speed ceiling is **300 rpm**, recording maximum forming torque is optional, and lubricant is permitted. That capability test is distinct from the brochure's assembly-torque recommendation and from an installed joint's strength or clamp-load requirement. [PR-180, PDF pages 8–9](https://www.duo-taptite.com/assets/files/TAPTITE-2000-Engineering-Guidlines.pdf#page=8)

## Source versions and limits

The inspected end-user specification is **PR-180, January 2008, revised May 2019**, with a separate **2013 copyright** notice. The brochure also prints **copyright 2013**; its download filename mentions a table correction dated October 16, 2019, but that filename is not an established printed edition date. Both files were accessed on **October 31, 2026 (PDT)** from the REMINC/CONTI product site's linked downloads. [PR-180 cover, PDF page 1](https://www.duo-taptite.com/assets/files/TAPTITE-2000-Engineering-Guidlines.pdf#page=1), [brochure, PDF page 12](https://www.duo-taptite.com/assets/files/TAPTITE-2000-REMINC-CONTI-VERSION-SP-Table-Corrected-10-16-19.pdf#page=12), [REMINC/CONTI TAPTITE 2000 page](https://www.duo-taptite.com/products/taptite-2000)

The brochure labels its tables as guidance, and PR-180's material sections distinguish their product requirements from specific applications. These sources do not establish a universal hole size, tightening torque, reuse allowance, or customer qualification. The full referenced ISO, SAE, and ANSI standards were not independently accessed; their names in a manufacturer document do not establish inspection of those editions or conformity of an unspecified supplied screw. [Brochure, PDF pages 4 and 12](https://www.duo-taptite.com/assets/files/TAPTITE-2000-REMINC-CONTI-VERSION-SP-Table-Corrected-10-16-19.pdf#page=4), [PR-180, PDF pages 7, 10 and 14](https://www.duo-taptite.com/assets/files/TAPTITE-2000-Engineering-Guidlines.pdf#page=7)

## Related reference

[Hardware and component references](../index.md) covers the broader assembly-process context.