One to three slots
Profiles with closed faces where nothing will be mounted. Cleaner appearance, easier to wipe, slightly stiffer, and useful on frame edges and door frames.
Modular framing extrusions
Aluminium T-Slot Profiles
Aluminium T-slot profiles are extrusions with undercut slots along each face, so T-nuts and bolts can be slid in anywhere along the length to join profiles and attach panels, guards and components without welding. Metline supplies metric 20 to 90 mm series and inch 10 and 15 series profiles in light, standard and heavy sections, cut and machined to length with matching fittings, to customers worldwide.
- Metric series
- 20, 30, 40, 45, 50, 60, 80, 90 mm
- Inch series
- 10 (1 in) and 15 (1.5 in)
- Alloys
- 6063-T5 / T6, 6061-T6
- Cut tolerance
- typically ±0.2 – 0.5 mm
What are aluminium T-slot profiles?
A T-slot profile is a square or rectangular extrusion, usually hollow, with a slot running the full length of one or more faces. The slot is narrower at the opening than inside, so a T-nut, hammer nut or bolt head slid into it is trapped and can be tightened at any point.
That single feature turns a length of aluminium into a building system. Frames are assembled with brackets, corner connectors and internal fasteners using hand tools, then adjusted, extended or taken apart and reused. There is no welding, no painting and no distortion, and the designer can move a mounting point by loosening one bolt. For machine builders, laboratories and production engineers this makes T-slot framing faster and often cheaper over the life of the equipment than welded steel.
Profiles are named by the size of the basic square in millimetres or inches and by the slot system. A "40 series" profile is based on a 40 × 40 mm square; a 4080 profile is two 40 mm modules side by side. Inch systems use 10 series (1 in) and 15 series (1.5 in) modules. Within each series, light, standard and heavy sections offer different wall thickness and stiffness for the same outside size.
T-slot profile series and slot sizes
The slot width must match the fasteners and accessories, so choose the series first and then the section. Slot geometry varies between systems (for example 8 mm "B-type" and 8 mm "I-type" slots in 40 series), so confirm compatibility before mixing profiles and fittings from different sources.
| Series | Base module | Typical slot opening | Approx. weight of square section | Typical use |
|---|---|---|---|---|
| 20 series | 20 × 20 mm | 6 mm | about 0.4 – 0.6 kg/m | 3D printers, small enclosures, models |
| 30 series | 30 × 30 mm | 8 mm | about 0.8 – 1.0 kg/m | Light frames, guards, displays |
| 40 series | 40 × 40 mm | 8 or 10 mm | about 1.4 – 1.9 kg/m | Workbenches, machine guards, conveyors |
| 45 series | 45 × 45 mm | 10 mm | about 1.6 – 2.1 kg/m | Machine frames, automation cells |
| 50 / 60 series | 50 or 60 mm | 10 – 12 mm | about 2.0 – 3.5 kg/m | Heavier frames, gantries |
| 80 / 90 series | 80 or 90 mm | 10 – 14 mm | about 4 – 8 kg/m | Machine bases, heavy gantries, robot stands |
| 10 series (inch) | 1.0 × 1.0 in | about 0.26 in | about 0.5 lb/ft | Light inch-based frames |
| 15 series (inch) | 1.5 × 1.5 in | about 0.32 in | about 1.0 lb/ft | Standard inch-based machine frames |
Weights and second moments of area vary by manufacturer and section weight class; a 40 × 40 mm standard section is typically around 8 – 10 cm⁴ about each axis. Use the data sheet of the exact profile for design.
Each series is also made in multiples (2040, 3060, 4080, 40160, 4590 and so on), with one slot per module face, and in special shapes: radius and quarter-round profiles for rounded corners, angled 30°, 45° and 60° profiles, profiles with one or more closed faces, and panel-mounting profiles. Our pages on 2020 and 2040, 3030 and 3060, 4040 and 4080 and 45 series cover each family in detail.
Slot layouts: from one slot to twelve
Four slots (standard)
One slot on every face; the most versatile profile and the default for frames built in three directions.
Double (e.g. 4080)
Two modules side by side with six slots; roughly four times the stiffness of a single profile in its strong direction.
Triple and quad (e.g. 40120, 8080)
Eight or more slots for machine bases, gantries and heavy uprights.
Radius and angled
Rounded or angled outer faces for safe corners and faceted frames.
Light, standard and heavy
Same outside size and slot, different wall and core thickness: choose by load and span, not by appearance.
Alloys, tempers and properties
Most T-slot profiles are extruded in 6063-T5 or T6. The alloy flows well through the complex dies needed for slots and internal cores, holds tight slot dimensions and gives a uniform anodised finish. Heavier structural profiles are sometimes made in 6061-T6 or 6005A-T6 for higher strength.
| Alloy and temper | Min. tensile | Min. yield | Typical hardness | Notes |
|---|---|---|---|---|
| 6063-T5 | 152 MPa (ASTM B221) | 110 MPa | about 60 HB | Standard for most systems |
| 6063-T6 / T66 | 207 – 245 MPa | 172 – 200 MPa | about 73 – 80 HB | Stiffer slot lips, better thread strength |
| 6005A-T6 | about 270 MPa | about 225 MPa | about 85 HB | Heavy structural sections |
| 6061-T6 | 260 MPa | 240 MPa | about 95 HB | High-strength frames and machined parts |
Values are specified minimums for thin walls (ASTM B221 / EN 755-2); 6063-T66 is an EN temper. Stiffness is the same for all of them: modulus about 69 – 70 GPa. Choosing a stronger alloy does not reduce deflection; choosing a larger or heavier section does.
Selecting a profile for load and deflection
- Define loads and spansEstimate the weight carried, any point loads (motors, operators leaning, tooling) and the unsupported span of each member.
- Set a deflection limitMachine frames commonly target about L/1000 to L/500 or a fixed value such as 0.5 mm; guards and enclosures can accept more.
- CalculateDeflection of a simply supported beam with a central load is F·L³ / (48·E·I). Use the profile's second moment of area (I) and E ≈ 70 GPa.
- Pick the seriesIf deflection is too high, move to a deeper profile (4080 instead of 4040) rather than a stronger alloy; depth increases I sharply.
- Check the jointsJoint stiffness often limits a T-slot frame. Use gussets, anchor fasteners or diagonal braces where rigidity matters, and size T-nuts to the load.
Common mistakes include mixing slot types from different systems, using a single small profile as a long unsupported beam, relying on one corner bracket where a gusset is needed, and forgetting that bolted T-slot joints can slip under shock or vibration unless anchor fasteners, pins or thread-locking are used.
Fasteners and accessories
| Group | Examples |
|---|---|
| Fasteners | T-nuts, hammer (drop-in) nuts, roll-in spring nuts, T-bolts, end-tapped fixings, anchor fasteners |
| Connectors | Corner brackets, gussets, joining plates, angle connectors, hinged and pivot joints |
| Feet and mobility | Levelling feet, floor brackets, castors, slider pads |
| Motion | Linear guides, slide bearings, rollers, drawer slides |
| Panels and covers | Panel retainers and gaskets for 4 – 10 mm panels, slot cover strips, end caps |
| Function | Handles, hinges, door latches, cable ducts, sensor and cylinder brackets |
Ordering profiles and fittings together keeps every slot and fastener compatible. Panels in polycarbonate, acrylic, ACP or mesh can be supplied cut to fit the frame.
Cutting, machining and finishing
Precision cutting
Square cuts to about ±0.2 – 0.5 mm with clean, burr-free ends; angled cuts for diagonal braces.
End tapping
Centre bores tapped (for example M6, M8, M10, M12) for end connectors and levelling feet.
Access holes
Counterbored holes for concealed connectors and wrench access, drilled to the system's standard positions.
CNC machining
Slots, pockets, holes for motors and sensors, and notching for flush joints.
Anodising
Clear (silver) as standard, typically 10 – 15 µm; black and other colours on request; harder films for wear areas.
Kitting
Profiles cut, labelled by part number and packed with fittings as a ready-to-assemble kit.
Profiles are normally ordered to EN 12020-2 precision tolerances, which control the outside size, slot dimensions, straightness and twist. Every delivery carries an EN 10204 3.1 certificate.
Where T-slot profiles are used
- Automation: machine frames, robot cells, gantries and pick-and-place structures
- Safety guarding: fences, enclosures and doors around machines
- Workstations: assembly benches, lean-manufacturing carts and flow racks
- Conveyors: side frames, supports and stands
- Laboratories and clean rooms: equipment frames and enclosures with smooth, cleanable surfaces
- 3D printers and CNC machines: 20 and 30 series frames for hobby and professional machines
- Displays and exhibitions: stands, shopfitting and signage frames
- Solar and vehicles: test rigs, roof racks and modular mounting frames
How to order T-slot profiles
- SpecifySeries and profile (e.g. 4040 standard, 8 mm slot), alloy, finish, each cut length and quantity, machining (end taps, access holes), and the fittings list or a frame drawing.
- QuoteWe confirm the die (existing or new), alloy, temper, finish, packing and delivery terms (EXW, FOB, CIF or DAP) for your destination.
- SampleFor new or appearance-critical sections, a short length or finish sample can be supplied for approval before the production run.
- ProcessProfiles are cut, tapped, drilled and machined to the cutting list, labelled, and packed with matching fittings.
- DocumentEach delivery carries a mill test certificate to EN 10204 3.1 with cast analysis and mechanical results; coating thickness reports and third-party inspection on request.
- ShipLengths are film-protected, bundled with spacers and packed in cartons, crates or on pallets for sea, air or road freight to your port or door.
References and standards
- ASTM B221 – Standard Specification for Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
- EN 755-2 – Aluminium and aluminium alloys: extruded rod/bar, tube and profiles, mechanical properties
- EN 12020-2 – Extruded precision profiles in alloys EN AW-6060 and EN AW-6063: tolerances on dimensions and form
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits (Teal Sheets)
- ISO 7599 – Anodizing of aluminium and its alloys: method for specifying decorative and protective anodic oxidation coatings
Aluminium (aluminum) T-slot profiles: frequently asked questions
What do the numbers 2020, 4040 and 4080 mean?
They give the outside size in millimetres: 2020 is 20 × 20 mm, 4040 is 40 × 40 mm, and 4080 is 40 × 80 mm (two 40 mm modules side by side). Inch systems use 10 series (1 in) and 15 series (1.5 in).
Can I mix profiles and fittings from different suppliers?
Only if the slot geometry matches. Profiles of the same series can have different slot shapes and openings, so check slot drawings or order profiles and fittings together.
Which T-slot size do I need?
20 and 30 series suit light frames and enclosures; 40 and 45 series suit benches, guards and most machine frames; 60 to 90 series suit machine bases and heavy gantries. Check deflection for long spans.
Is 6061 better than 6063 for T-slot profiles?
6061-T6 is stronger, but both have the same stiffness, so deflection is unchanged. For most frames 6063-T5 or T6 is sufficient; a larger profile is the better way to reduce deflection.
How accurately can profiles be cut?
Typical saw-cut tolerance is about ±0.2 – 0.5 mm, with square, deburred ends. End tapping and access holes can be added to the cutting list.
Do you supply T-slot frames as kits?
Yes. Profiles can be cut, machined and labelled to your drawing and packed with matching connectors, feet and panels, ready to assemble.
Building a frame with T-slot profiles?
Send the series, cutting list, machining and fittings, and we will confirm compatibility and quote a delivered price.
