Subsequent Nut for 8 mm T-Slot Aluminium Profiles M5 M6 M8

OEM / ODM Available Free Sample Available RoHS, REACH, material certificate for stainless steel

Subsequent T-slot nut for 30 and 40 series aluminium profiles. M5, M6 and M8 threads. Slides in from profile end face after assembly. Round or square body. Rescue fastener for retrofit.

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

Material	Carbon steel
Alloy Grade	Carbon steel C1035, stainless A2 / A4
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
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 and stainless 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	RoHS, REACH, material certificate for stainless steel

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01What is a subsequent T-slot nut?

How does a subsequent nut differ from a pre-set nut?

A subsequent nut slides into the groove from the end face of an already-assembled profile. You do not need to disassemble the frame or plan the nut position in advance. A pre-set nut is placed from the slot mouth before the profiles are connected. Both types carry the same pull-out load once the bolt is tightened — the difference is entirely in the assembly sequence.

When is a subsequent nut the right choice?

When the frame is already built and you need to add a fitting, bracket or panel that was not planned in the original assembly. This happens in retrofit work, prototype iteration, and when an assembler forgets to place a pre-set nut at a joint. The subsequent nut is the rescue fastener — it lets you add a mounting point without taking the frame apart.

Is a subsequent nut as strong as a pre-set nut?

Yes. Once the bolt is tightened, both types seat the same way behind the groove lip. The pull-out force is determined by the nut body engagement and the groove wall strength, not by how the nut entered the slot. The load reduction myth comes from the fact that subsequent nuts are sometimes used in worn grooves (because the frame has been handled), which reduces the pull-out — but that is a groove condition issue, not a nut type issue.

02The rescue scenario: adding a fitting to a built frame

The typical use case for a subsequent nut is a frame that is already assembled and needs a new mounting point. The scenario plays out as follows: the frame is built, the brackets and panels are installed, and then someone discovers that a cable clip, a sensor or a support bracket needs to be added at a position where no nut was placed.

Without a subsequent nut, the options are to disassemble the joint (which may require removing panels and brackets to access the profile end), or to drill and tap a hole in the profile wall (which weakens the section). The subsequent nut lets you slide a nut in from the nearest open end of the profile, push it to the required position, and bolt on the fitting.

Step 1: Identify the nearest open end of the profile. If the end is capped, remove the cap.
Step 2: Slide the subsequent nut into the groove mouth at the end face. The nut body should enter smoothly — if it catches, check for burrs from the profile cut.
Step 3: Push the nut along the groove to the target position. Use a probe or a bolt from the outside to locate it.
Step 4: Insert the bolt through the fitting and thread it into the nut. Tighten to the recommended torque.

If the profile end is not accessible (e.g. it is inside a closed frame), you may need to use a pre-set nut with a spring tab instead, which can be pressed in from the slot mouth. But this requires a gap in the groove lip — the slot mouth is normally narrower than the nut body, so a pre-set nut cannot be retrofitted without a special tool.

03Subsequent vs pre-set: assembly time comparison

The time difference between subsequent and pre-set nuts depends on the number of fittings per profile and the distance the nut must slide. For a single nut on a short profile, the difference is negligible. For many nuts on a long profile, pre-set is significantly faster because all nuts are placed in one pass before assembly.

Scenario	Pre-set time	Subsequent time	Difference
1 nut, 300 mm profile	5 sec	8 sec	+3 sec
4 nuts, 1000 mm profile	12 sec	35 sec	+23 sec
8 nuts, 1200 mm profile	20 sec	70 sec	+50 sec
1 nut retrofit (frame built)	n/a	15 sec	rescue only
Forgotten nut (disassemble to add)	120 sec	15 sec	+105 sec saved

The retrofit scenario is where the subsequent nut shines: adding a forgotten pre-set nut would require disassembling the joint (about 2 minutes), whereas sliding in a subsequent nut takes about 15 seconds. The 105 second saving per forgotten nut is why every assembly kit should include a few subsequent nuts as spares.

04Pull-out force: subsequent vs pre-set

There is a persistent belief that subsequent nuts are weaker than pre-set nuts. This is not true in terms of the nut design — both types have the same body width, the same engagement with the groove lip, and the same pull-out rating once bolted. The difference in measured pull-out comes from the groove condition, not the nut type.

Pre-set nuts are typically installed on new, clean grooves before the profile is handled. Subsequent nuts are often installed on grooves that have been through assembly, handling and possibly wear. The groove may have burrs from cutting, anodising build-up, or slight deformation from other bolts being tightened nearby. These conditions reduce the pull-out for subsequent nuts — but if the groove is in good condition, the pull-out is identical.

Condition	Pre-set pull-out	Subsequent pull-out	Ratio
New, mill finish groove	1.5 kN (M6)	1.5 kN (M6)	1.00
New, anodised groove	1.3 kN (M6)	1.3 kN (M6)	1.00
Handled, minor burrs	1.5 kN (M6)	1.2 kN (M6)	0.80
Worn, several cycles	1.3 kN (M6)	1.0 kN (M6)	0.77
Damaged groove lip	1.0 kN (M6)	0.8 kN (M6)	0.80

The ratio column shows that subsequent nuts are only weaker when the groove is in worse condition — which is correlated with subsequent nut use but not caused by it. If you install a subsequent nut in a clean, new groove, the pull-out is identical to a pre-set nut.

05Thread and series compatibility

Subsequent nuts are available for 30 and 40 series grooves. The 20 series groove (6 mm) is too narrow for a round body to slide smoothly from the end — the body catches on the slot mouth. For 20 series, pre-set nuts with spring tabs are the standard option.

Series	Groove	Thread	Body type	Sliding force
30 series	8 mm	M6	round	0.5 to 1.5 N
40 series	10 mm	M8	round	0.5 to 1.5 N
30 series	8 mm	M5 (reducer)	round	0.5 to 1.5 N
40 series	10 mm	M6 (reducer)	round	0.5 to 1.5 N
30 series	8 mm	M6	square	1.5 to 3.0 N
40 series	10 mm	M8	square	1.5 to 3.0 N

Square body subsequent nuts have higher sliding force because the flat sides drag on the groove walls. The benefit is that they do not rotate under torque — see the separate square nut page for details.

06When to choose subsequent over pre-set

Choose subsequent nuts

Retrofit or modification of an existing frame
Prototype where fitting positions are uncertain
Frames where the profile ends are accessible for sliding
Forgotten nut rescue — avoid disassembling the joint
Frames with few fittings per profile (1 to 3)

Choose pre-set nuts

Production runs of identical frames
Frames with many fittings per profile (8+ per metre)
Frames where profile ends will be capped or sealed
Automated assembly where nut placement is jig-guided
When you want maximum assembly speed at final bolt-up

07The maximum load question: does the nut type matter?

The short answer is no — once the bolt is tightened, the nut type does not affect the load capacity. The pull-out force is carried by the nut body bearing against the back of the groove lip, and both pre-set and subsequent nuts have the same body geometry. The only thing that matters is the groove condition.

However, there is a practical consideration: subsequent nuts are often used in retrofit applications where the groove may have been damaged by previous use. If the groove lip is rolled, cracked or worn, the pull-out will be reduced regardless of nut type. For structural joints in existing frames, inspect the groove before relying on a subsequent nut.

Load type	Pre-set nut	Subsequent nut	Notes
Pull-out (axial)	1.5 kN (M6)	1.5 kN (M6)	same body geometry
Shear (lateral)	carried by bolt, not nut	same	nut type irrelevant
Vibration retention	60 per cent	60 per cent	neither has anti-rotation
Cyclic load	good if groove is new	good if groove is new	groove condition matters
Overload failure	groove lip deforms	groove lip deforms	same failure mode

08Failure modes to design out

What goes wrong	Why it happens	Design it out by
Nut cannot slide into groove	burr from profile cut at the end face blocks entry	deburr the end face before inserting; use a file or deburring tool
Nut sticks partway along groove	anodising build-up or corrosion in the groove	clean the groove with a brush; check width with a gauge
Nut rotates and thread position shifts	round body has no anti-rotation feature	use a square body subsequent nut for precision applications
Pull-out lower than expected	groove lip deformed by previous over-torque	inspect groove; use a new profile section if lip is damaged
Nut lost inside groove during positioning	no anti-drop tab; nut can slide past the target	use a bolt from outside to feel the nut position; or mark the groove

09What to specify when ordering

Procurement checklist for subsequent T-slot nuts

Confirm the profile series: 30 (8 mm groove) or 40 (10 mm). Subsequent nuts are not recommended for 20 series.
Confirm the thread size: M6 or M8 for direct fit, M5 or M6 for reducer configurations.
Confirm the body type: round for lowest friction, square for anti-rotation. Both are subsequent type (slide from end).
Confirm the material: carbon steel zinc plated, or stainless steel A2 / A4.
Confirm the quantity per size. Price breaks apply at 100, 500 and 1000 pieces.
Keep a small stock of subsequent nuts as spares for retrofit work, even if the primary frame uses pre-set nuts.

10Questions buyers ask

Are subsequent nuts as strong as pre-set nuts?

Yes, once the bolt is tightened. Both types have the same body geometry and the same pull-out rating. The difference is only in how the nut enters the groove — pre-set from the mouth before assembly, subsequent from the end after assembly.

Can I use subsequent nuts on 20 series profiles?

Not recommended. The 6 mm groove is too narrow for a round body to slide smoothly from the end. For 20 series, use pre-set nuts with spring tabs.

How far can a subsequent nut slide along the groove?

As far as the groove is open and clean. On a 6 m profile, a nut can slide the full length if the groove is free of obstructions. In practice, sliding force increases with distance due to friction, so a probe or a bolt is used to push the nut to position.

Do subsequent nuts have an anti-drop tab?

No. Subsequent nuts are designed to slide freely along the groove, so they have no tab. Once the bolt is tightened, the clamping force holds the nut in position. For pre-assembly holding, use a pre-set nut with a spring tab instead.

What body type should I choose?

Round for lowest friction and fastest sliding, square for anti-rotation and positioning accuracy. For vibration resistance, use the anti-torsion winged type (see the separate anti-torsion nut page).

What is the lead time?

Stocked carbon steel sizes ship in 2 to 3 days. Stainless steel and custom sizes have a lead time of about 2 weeks.

What we need to quote subsequent T-slot nuts

The profile series (30 or 40) and the groove width.
The thread size: M6 or M8 standard, M5 or M6 reducer.
The body type: round (standard) or square (anti-rotation).
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.

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