TVS Prevailing Torque Nuts – M6 to M24, grades 8 and 10

TVS Sundram Fasteners Prevailing Torque Nuts are all-metal prevailing torque hex nuts made by Sundram Fasteners Limited to DIN 6925 / ISO 7042 / DIN 980 (type V), in sizes from M6 to M24, property classes 8 and 10, supplied in zinc phosphate and 3 plated or coated finishes (listed below). They are the DIN 980 type V design: two or three dents in the top of the nut deform the thread slightly, so the nut resists turning on the bolt and holds its clamp load under vibration and heat where a nylon insert would not survive.

This item is supplied at a price on request; tell us the sizes, pitch, property class and finish you need and we will quote.

Jai Enterprises is an authorised distributor of TVS Sundram Fasteners high tensile fasteners and supplies them from Bhilai and Raipur all over Chhattisgarh - Bhilai, Raipur, Durg, Korba, Bilaspur, Raigarh, Jagdalpur, Kanker, Ambikapur and every other district - and across India.

Is this the right one for you?

Check these three things before you order:

• Your thread is metric coarse pitch (M sizes).
• The size you need is within M6 to M24.
• The joint sees vibration or heat, or is opened and refitted a few times, so you want an all-metal lock nut rather than a nylon insert.

At a glance

• Brand: TVS Sundram Fasteners (Sundram Fasteners Limited, TVS group)
• Product: Prevailing Torque Nuts
• Standard: DIN 6925 / ISO 7042 / DIN 980 (type V)
• Sizes: M6 to M24
• Form: hexagon with 2 or 3 dents in the top
• Property class: 8 and 10
• Material: Steel
• Surface finish: zinc phosphate, trivalent iridescent, trivalent white and zinc flake coating (Geomet / Magni / Delta)
• Forging: cold forging
• Price: price on request - tell us the sizes, pitch, property class and finish
• Supplied by: Jai Enterprises, Bhilai and Raipur - to every district of Chhattisgarh and across India, +91 9340081159

Specifications and dimensions

• Standard: DIN 6925 / ISO 7042 / DIN 980 (type V)
• Material: high tensile steel; nut classes to ISO 898-2
• Property class: 8 and 10
• Surface finish options: zinc phosphate, trivalent iridescent, trivalent white and zinc flake coating (Geomet / Magni / Delta)
• Manufacture: cold forging
• Marking: TVS brand mark on the face and the property class mark
• M6: pitch 1.0; across flats 10.00 mm, across corners 11.05 mm, thickness 6.00 mm
• M8: pitch 1.25; across flats 13.00 mm, across corners 14.38 mm, thickness 8.00 mm
• M10: pitch 1.5; across flats 16.00 mm, across corners 17.77 mm, thickness 10.00 mm
• M12: pitch 1.75; across flats 18.00 mm, across corners 20.03 mm, thickness 12.00 mm
• M14: pitch 2.0; across flats 21.00 mm, across corners 23.35 mm, thickness 14.00 mm
• M16: pitch 2.0; across flats 24.00 mm, across corners 26.75 mm, thickness 16.00 mm
• M20: pitch 2.5; across flats 30.00 mm, across corners 32.95 mm, thickness 20.00 mm
• M24: pitch 3.0; across flats 36.00 mm, across corners 39.55 mm, thickness 23.90 mm
• Note: M24: the printed catalogue table transposes the across-flats and across-corners figures; shown here the right way round
• Source: SFL's technical product catalogue (September 2026 edition) and SFL's digital product catalogue; dimensions in mm

Why choose TVS Sundram Fasteners

• Made by Sundram Fasteners Limited, a TVS group company making high tensile fasteners since 1966: first Indian company with ISO 9000, IATF 16949:2016 certified, Deming Prize 2018 for 17 plants.
• Every lot is backed by a BIS, NABL and ISO/IEC 17025 certified laboratory - tensile, fatigue, torque-tension, salt spray and coating thickness testing - as described in SFL's technical product catalogue (September 2026 edition).
• Made to a named standard - DIN 6925 / ISO 7042 / DIN 980 (type V) - with the dimensions published in SFL's technical catalogue, so parts interchange with any other maker's to the same standard.
• The grade mark on each part shows its property class (8 and 10), so site inspection is simple.
• A choice of finishes - zinc phosphate, trivalent iridescent, trivalent white and zinc flake coating (Geomet / Magni / Delta) - from plain indoor use to zinc flake coating for outdoor and corrosive service.
• Keeps the joint tight under vibration without extra lock washers or thread-locking compound.

How to choose and fit

1. Match the thread of the bolt exactly - size and pitch (or threads per inch) - from the table above.
2. Match the class: class 8 nuts with 8.8 bolts, class 10 with 10.9 (nut class not lower than the bolt class).
3. Fit a washer under the nut where the joint face is soft, slotted or painted.
4. Tighten to the specified torque with the bolt held; the prevailing torque of the dented thread is felt before the nut seats - allow for it in the tightening torque.

Where it is used

• engine, exhaust and chassis joints that run hot
• rotating and vibrating machinery
• railway and heavy vehicle assemblies
• joints that are dismantled and refitted

Related products

• TVS Sundram Fasteners SunLoc Nylon Insert Nuts, DIN 982 / ISO 7040 - the nylon insert lock nut
• TVS Sundram Fasteners Hex Nuts, ISO 4032 metric - the plain hex nut

Frequently asked questions

What is the price of Prevailing Torque Nuts?

It is supplied at a price on request. Send the sizes, grade, finish and quantity to Jai Enterprises on +91 9340081159 and we will quote from the current SFL list.

How is this different from a nylon insert nut?

The locking action comes from dents in the top of the nut that deform the thread, not from a nylon ring, so it keeps working at temperatures that would soften nylon and through several refits (ISO 2320 tests the prevailing torque over five assembly cycles).

Are TVS Prevailing Torque Nuts available in Chhattisgarh?

Yes. Jai Enterprises, an authorised distributor of TVS Sundram Fasteners, supplies from Bhilai and Raipur all over Chhattisgarh and across India. Call +91 9340081159 or use the enquiry form.

Can I get a different finish or a non-listed size?

Yes. The standard finishes are zinc phosphate, trivalent iridescent, trivalent white and zinc flake coating (Geomet / Magni / Delta); other finishes and sizes or lengths outside the range are quoted on enquiry from SFL.

How to order

Call Jai Enterprises on +91 9340081159 or send an enquiry with the sizes, pitch, property class, finish and quantity of Prevailing Torque Nuts you need; they are supplied at a price on request. We supply from Bhilai and Raipur all over Chhattisgarh - Bhilai, Raipur, Durg, Korba, Bilaspur, Raigarh, Jagdalpur, Kanker, Ambikapur and every other district - and across India.