Anti-torsion Subsequent Nut for 8 mm T-Slot Aluminium Profiles

OEM / ODM Available Free Sample Available Vibration test report on request, RoHS, REACH, material certificate for stainless steel

Anti-torsion subsequent T-slot nut with twin wings for 30 and 40 series aluminium profiles. M6 and M8 thread sizes. Vibration resistant, slides in from profile end.

Wholesale Price Quoted per piece, price breaks at 100 / 500 / 1000 per per piece

Material	Carbon steel
Alloy Grade	Carbon steel C1035, spring steel 65Mn for wings
Temper	custom
Section Size	n/a (piece part)
Slot	Fits 8 mm and 10 mm groove widths (30/40 series)
Length	n/a (piece part, sold per nut)
Tolerance	Thread 6H, body width +/-0.1 mm, wing span +/-0.05 mm
Surface	Zinc plated / stainless steel A2 or A4
MOQ	No MOQ for stock sizes; 500 pieces for custom sizes
Lead Time	Stocked sizes ship in 2 to 3 days; custom sizes about 2 weeks
Loading Port	Shanghai, Ningbo, Qingdao
Supply Ability	Stocked carbon steel sizes in volume; stainless and custom sizes produced to order
Payment Terms	T/T 30 per cent deposit, balance against copy of B/L; L/C at sight for larger orders
Trade Terms	FOB, CIF, CFR, EXW
Certifications	Vibration test report on request, RoHS, REACH, material certificate for stainless steel

Request a Quote Reply within 24 hours

01What is an anti-torsion subsequent nut?

How does an anti-torsion nut stop itself from rotating?

The nut body has twin wings that extend along the slot axis and press against the inner walls of the groove. When the bolt is tightened, the wings bite into the groove lip surface, creating a mechanical lock that prevents the nut from rotating around the bolt axis. A standard subsequent nut has a round or hex body that relies on friction alone, which can be overcome by vibration.

When do you need an anti-torsion nut instead of a standard one?

When the joint is subject to vibration, cyclic loading or thermal cycling. Machine tool spindles, pneumatic actuators, conveyor mounts and any frame bolted to a vibrating base are the primary applications. For static frames — workbenches, display stands, enclosures with no moving parts — a standard subsequent nut is sufficient.

Can I use anti-torsion nuts everywhere for safety?

You can, but it is not cost-effective. Anti-torsion nuts cost about 2.5 times a standard subsequent nut. Using them on a static workbench frame adds cost without benefit. The correct approach is to identify the vibrating joints and use anti-torsion nuts there, and standard nuts elsewhere. Section 06 gives the selection logic.

02How the anti-rotation wings work

The anti-rotation mechanism is purely mechanical — no thread lock, no spring washer, no nylon insert. The nut body has two wings that run parallel to the slot axis. When the nut is seated in the groove and the bolt is tightened, the clamping force pushes the wings against the inner surface of the groove lip.

The wings have a serrated edge that bites into the aluminium groove surface. The serrations are about 0.2 mm deep, which is enough to create a mechanical interlock without damaging the groove structure. Once engaged, the nut cannot rotate until the bolt is loosened and the clamping force is released.

This is different from a nylon insert nut (which uses friction from a deformed nylon ring) or a spring washer (which maintains tension but does not prevent rotation). The wing interlock is positive and does not degrade with temperature or chemical exposure.

Feature	Anti-torsion wings	Spring washer	Thread locker
Mechanism	mechanical interlock (serration)	tension (spring force)	chemical bond
Reusability	yes (serrations re-bite)	limited (washer fatigues)	no (re-apply each time)
Temperature	no limit (mechanical)	limited by spring temper	limited by adhesive cure
Vibration	excellent	moderate	good (if cured properly)
Cost per nut	approx. 2.5x standard	approx. 1.2x standard	approx. 1.5x standard
Maintenance	inspect for wing wear	replace if loose	re-apply if disassembled

The spring washer is the cheapest anti-loosening measure but the least effective under high-frequency vibration. Thread locker is effective but single-use and temperature-limited. The anti-torsion wing nut is the only option that is reusable, temperature-unlimited and mechanically positive.

03Vibration test results

We tested three nut types on a 40 series profile with an M8 bolt torqued to 12 Nm. The test rig applied sinusoidal vibration from 10 to 500 Hz at 10 g acceleration, sweeping through the range for 2 hours per axis (X, Y and Z). The bolt torque was measured before and after each test, and the clamping force was monitored continuously with a load cell.

The results show the anti-torsion nut maintained 95 per cent of initial clamping force after all three axes. The standard subsequent nut lost 40 per cent, and the spring washer version lost 25 per cent. The thread locker (medium strength, fully cured) maintained 90 per cent but could not be re-torqued without removing and re-applying the adhesive.

Nut type	Torque before (Nm)	Torque after (Nm)	Retention
Standard subsequent	12.0	7.2	60 per cent
Spring washer	12.0	9.0	75 per cent
Anti-torsion wings	12.0	11.4	95 per cent
Thread locker (medium)	12.0	10.8	90 per cent

Test conditions: 40 series profile, M8 bolt, 12 Nm initial torque, sinusoidal vibration 10 to 500 Hz at 10 g, 2 hours per axis. Results are indicative and will vary with bolt grade, surface finish and groove condition.

04Series and thread compatibility

Anti-torsion subsequent nuts are available for 30 and 40 series grooves. The 20 series groove (6 mm) is too narrow for effective wing engagement, so anti-torsion nuts are not made for 20 series. For 20 series frames subject to vibration, thread locker is the recommended solution.

Series	Groove	Thread	Wing span	Bolt torque (max)
30 series	8 mm	M6	7.2 mm	10 Nm
40 series	10 mm	M8	9.2 mm	25 Nm
30 series	8 mm	M5 (reducer)	7.2 mm	6 Nm
40 series	10 mm	M6 (reducer)	9.2 mm	10 Nm

The maximum bolt torque is limited by the groove wall strength, not by the nut or bolt. Exceeding the listed torque will deform the groove lip and reduce the effective wing engagement on future installations.

05Anti-torsion vs spring washer vs thread locker

Three options exist for preventing nut loosening under vibration, and each has a distinct profile of strengths and weaknesses. The choice depends on four factors: vibration severity, temperature range, maintenance accessibility and cost.

Choose anti-torsion nuts

Joints subject to high-frequency vibration (pneumatic, spindle, conveyor mounts)
Temperature extremes where adhesives and spring washers degrade
Joints that will be disassembled and reassembled regularly
Frames where maintenance access is limited — no need to re-apply thread locker
Applications where the cost of loosening is high — safety critical joints

Choose another method

Low-vibration static frames — standard nuts are sufficient
One-time assembly — thread locker is cheaper if never disassembled
20 series grooves — too narrow for wings; use thread locker
Budget-constrained projects where spring washers give adequate protection
When the bolt will be retorqued frequently — thread locker cannot be re-applied easily

06Cost comparison across the three options

The cost difference between the three options is not just the unit price of the nut. Thread locker has a hidden cost in labour (cleaning, applying, curing time) and in single-use waste. Spring washers are cheap but need replacement if they take a set. Anti-torsion nuts are the most expensive per piece but have no hidden labour or consumable cost.

Item	Standard nut	Spring washer	Anti-torsion nut	Thread locker
Unit cost (M8)	0.15 USD	0.18 USD	0.38 USD	0.23 USD + 0.10 USD adhesive
Labour per joint	5 sec	7 sec	5 sec	20 sec (apply + cure)
Reusable	yes	limited	yes	no
Hidden cost	none	washer replacement	none	curing time, cleaning
Total per joint (10 cycles)	1.50 USD	2.10 USD	3.80 USD	3.30 USD

Costs are indicative for M8 nuts at 500 piece quantity. The total per joint over 10 assembly cycles assumes the same joint is disassembled and reassembled 10 times. For one-time assembly, thread locker is cheaper than anti-torsion nuts.

07Failure modes to design out

What goes wrong	Why it happens	Design it out by
Wings wear smooth after repeated use	serrations lose edge after 20 to 30 cycles on hard-anodised grooves	use on mill finish grooves; replace nuts on high-cycle joints
Nut will not slide into groove	wings are wider than the slot mouth, designed to seat from the end	anti-torsion nuts are subsequent type — slide from the end face only
Groove lip deforms under high torque	bolt torque exceeds groove wall strength	stay within the maximum torque for each series (10 Nm M6, 25 Nm M8)
Wings do not engage in worn groove	groove lip has been deformed by previous over-torque	inspect groove condition; use a new section if lip is rolled or cracked
Bolt still loosens despite anti-torsion nut	wing serrations are on the groove, not the bolt thread — bolt can still back out	use a thread locker in addition to the anti-torsion nut for safety-critical joints

08What to specify when ordering

Procurement checklist for anti-torsion nuts

Confirm the profile series: 30 (8 mm groove) or 40 (10 mm). Anti-torsion nuts are not available for 20 series.
Confirm the thread size: M6 or M8 for direct fit, M5 or M6 for reducer configurations.
Confirm the bolt torque range for your application. The maximum torque is limited by the groove, not the nut.
Confirm the groove condition: new grooves give the best wing engagement. Hard-anodised grooves wear the serrations faster.
Specify the quantity per size. Price breaks apply at 100, 500 and 1000 pieces.
For safety-critical joints, consider specifying thread locker in addition to anti-torsion nuts.

09Terms used on this page

Anti-torsion wing: A projection on the nut body that runs parallel to the slot axis and presses against the groove inner wall to prevent rotation under load.
Subsequent nut: A T-slot nut that slides into the groove from the end face of an already-assembled profile.
Serration: Small teeth on the wing edge that bite into the aluminium groove surface to create a mechanical interlock.
Spring washer: A split or wave washer placed under the bolt head or nut that maintains tension to resist loosening under vibration.
Thread locker: An anaerobic adhesive applied to the bolt thread that cures to a solid, preventing rotation. Available in low, medium and high strength.
Vibration retention: The percentage of initial bolt torque remaining after a vibration test cycle. Higher is better.

10Questions buyers ask

Are anti-torsion nuts reusable?

Yes. The wing serrations re-engage each time the bolt is tightened. After about 20 to 30 cycles on a hard-anodised groove, the serrations may wear smooth. On mill finish grooves, the nut will outlast the profile.

Can I use anti-torsion nuts on 20 series profiles?

No. The 6 mm groove is too narrow for effective wing engagement. For 20 series frames subject to vibration, use a medium-strength thread locker on the bolt thread.

Do anti-torsion nuts replace thread locker entirely?

In most vibration applications, yes. For safety-critical joints where failure could cause injury or significant damage, use both an anti-torsion nut and a medium-strength thread locker as a belt-and-suspenders approach.

What is the maximum bolt torque?

For 30 series with M6, the maximum is 10 Nm. For 40 series with M8, the maximum is 25 Nm. These limits are set by the groove wall strength, not by the nut or bolt. Exceeding them will deform the groove lip.

How do anti-torsion nuts compare in cost?

They are about 2.5 times the cost of a standard subsequent nut. Over 10 assembly cycles, the total cost is competitive with thread locker because the anti-torsion nut has no labour or consumable cost for re-application.

Can you supply the matching bolts?

Yes. We supply M6 and M8 T-slot bolts in lengths from 10 mm to 30 mm, in carbon steel and stainless steel. Specify the thread, length and material when ordering.

What we need to quote anti-torsion nuts

The profile series (30 or 40) and the groove width for each joint.
The thread size: M6 or M8 standard, M5 or M6 reducer on request.
The material: carbon steel zinc plated, or stainless steel.
The quantity per size, with total across all sizes.
Whether you need matching bolts and at what lengths.
Any certification requirement: vibration test report, material certificate, or RoHS / REACH.

Send those six items and the quotation comes back with the unit price at each quantity break, the vibration test data sheet, and the lead time for stocked and non-stocked sizes. Browse the full connecting elements range for related fasteners.