Tooling
Sharp, polished carbide inserts with high positive rake reduce built-up edge. HSS form tools work well on cam-type screw machines.
Hexagon bar for turned parts
6061 Aluminium Hex Bar (T6, T6511)
6061 hex bar is the starting stock for nuts, fittings, standoffs and couplings that need flats for a spanner without milling them in. Metline supplies 6061 hexagon bar in cold-finished T6 and extruded T6511, from about 6 to 100 mm (1/4 to 4 in) across flats, cut to length and certified to ASTM B211, B221 or EN standards, to buyers worldwide.
- Alloy
- 6061
- Tempers
- T6 (cold-finished), T6511 (extruded)
- Across flats
- about 6 – 100 mm
- Standards
- ASTM B211 · B221 · EN 755-2
Why use 6061 hex bar?
Starting a part from hexagon stock means the six flats already exist: the lathe only has to face, drill, tap and part off. For hydraulic and pneumatic fittings, nuts, spacers, standoffs, valve bodies and electrical terminals, that saves a milling operation on every piece and is the reason hex bar is a staple of screw-machine and CNC lathe shops.
6061 is the general-purpose alloy for this work. In T6 it gives a typical yield of about 276 MPa, enough for threaded fittings under moderate load; it machines with short chips; it anodises well for colour-coding and corrosion protection; and, unlike free-machining 2011, it can be welded and used in damp or outdoor service.
There are two production routes. Cold-finished hex (T6) is drawn through a die after extrusion: closer across-flats tolerance, sharper corners and a bright surface, ideal when the flats are a finished surface on the part. Extruded hex (T6511) is stretched for stress relief: slightly more generous tolerance and corner radii, but available in larger sizes and more stable when the part is hollowed out.
6061 composition (wt %)
Limits per the Aluminum Association registration, as used in ASTM B211, B221 and EN 573-3. The lot analysis is reported on the mill certificate.
| Element | Minimum | Maximum |
|---|---|---|
| Magnesium (Mg) | 0.80 | 1.20 |
| Silicon (Si) | 0.40 | 0.80 |
| Copper (Cu) | 0.15 | 0.40 |
| Chromium (Cr) | 0.04 | 0.35 |
| Iron (Fe) | — | 0.70 |
| Manganese (Mn) | — | 0.15 |
| Zinc (Zn) | — | 0.25 |
| Titanium (Ti) | — | 0.15 |
| Others, each / total | — | 0.05 / 0.15 |
| Aluminium (Al) | Remainder |
Mechanical properties of 6061 hex bar
| Product and temper | Tensile min. | Yield min. | Elongation min. | Typical hardness |
|---|---|---|---|---|
| Cold-finished T6 / T651, ASTM B211 | 290 MPa / 42 ksi | 240 MPa / 35 ksi | 10 % | 95 HB |
| Extruded T6 / T6511, ASTM B221 | 260 MPa / 38 ksi | 240 MPa / 35 ksi | 8 – 10 % | 95 HB |
| Extruded T6, EN 755-2 (≤ 200 mm) | 260 MPa | 240 MPa | 8 % | — |
| Typical T6 values | 310 MPa | 276 MPa | 12 % | 95 HB |
For hex bar, the size used to select the tensile band is the across-flats dimension. Elongation minimums vary with size; the certificate states the applicable values.
Physical properties of 6061-T6
- Density
- 2.70 g/cm³ (0.0975 lb/in³)
- Modulus of elasticity
- 68.9 GPa (10,000 ksi)
- Shear strength (typical)
- 207 MPa (30 ksi)
- Thermal conductivity
- 167 W/m·K
- Electrical conductivity
- 43 % IACS
- Coefficient of thermal expansion
- 23.6 µm/m·°C (20 – 100 °C)
- Melting range
- 582 – 652 °C
6061-T6 or 6061-T6511 hex bar?
| Point | Cold-finished T6 | Extruded T6511 |
|---|---|---|
| Production | Extruded, then cold drawn, heat-treated | Extruded, heat-treated, stretched and straightened |
| Across-flats tolerance | Tighter | Wider |
| Corners | Sharp or very small radius | Small radius, more visible |
| Surface | Bright, drawn | Extruded mill finish |
| Residual stress | Some; can move on deep boring | Low; stable when machined |
| Typical size range | about 6 – 50 mm (1/4 – 2 in) | about 10 – 100 mm (3/8 – 4 in) |
Rule of thumb: if the flats will be seen or gripped by a spanner as delivered, choose cold-finished T6. If the part is bored out heavily or is larger than about 50 mm, extruded T6511 is more practical and usually cheaper.
6061 hex bar sizes, across-corner dimensions and weights
For a sharp-cornered hexagon, the across-corners dimension is 1.1547 × the across-flats size; this decides the minimum collet, chuck or bar-feeder bore. Weight per metre is 0.002338 × s² kg (s = across flats in mm, density 2.70 g/cm³). Real bars with rounded corners weigh slightly less.
| Across flats (mm) | Across corners (mm) | Area (mm²) | kg per metre |
|---|---|---|---|
| 6 | 6.9 | 31.2 | 0.084 |
| 8 | 9.2 | 55.4 | 0.150 |
| 10 | 11.5 | 86.6 | 0.234 |
| 12 | 13.9 | 124.7 | 0.337 |
| 13 | 15.0 | 146.4 | 0.395 |
| 14 | 16.2 | 169.7 | 0.458 |
| 17 | 19.6 | 250.3 | 0.676 |
| 19 | 21.9 | 312.6 | 0.844 |
| 22 | 25.4 | 419.2 | 1.13 |
| 24 | 27.7 | 498.8 | 1.35 |
| 27 | 31.2 | 631.3 | 1.70 |
| 30 | 34.6 | 779.4 | 2.10 |
| 32 | 37.0 | 886.8 | 2.39 |
| 36 | 41.6 | 1122.4 | 3.03 |
| 41 | 47.3 | 1455.8 | 3.93 |
| 46 | 53.1 | 1832.5 | 4.95 |
| 50 | 57.7 | 2165.1 | 5.85 |
| 55 | 63.5 | 2619.7 | 7.07 |
| 60 | 69.3 | 3117.7 | 8.42 |
| 70 | 80.8 | 4243.5 | 11.46 |
| 80 | 92.4 | 5542.6 | 14.96 |
| 100 | 115.5 | 8660.3 | 23.38 |
Inch sizes, as stocked for North American and imperial designs:
| Across flats (in) | Across flats (mm) | Across corners (in) | lb per foot |
|---|---|---|---|
| 1/4 | 6.35 | 0.289 | 0.063 |
| 5/16 | 7.94 | 0.361 | 0.099 |
| 3/8 | 9.52 | 0.433 | 0.143 |
| 7/16 | 11.11 | 0.505 | 0.194 |
| 1/2 | 12.70 | 0.577 | 0.253 |
| 9/16 | 14.29 | 0.650 | 0.321 |
| 5/8 | 15.88 | 0.722 | 0.396 |
| 3/4 | 19.05 | 0.866 | 0.570 |
| 7/8 | 22.22 | 1.010 | 0.776 |
| 1 | 25.40 | 1.155 | 1.014 |
| 1-1/8 | 28.57 | 1.299 | 1.283 |
| 1-1/4 | 31.75 | 1.443 | 1.584 |
| 1-1/2 | 38.10 | 1.732 | 2.281 |
| 1-3/4 | 44.45 | 2.021 | 3.104 |
| 2 | 50.80 | 2.309 | 4.055 |
| 2-1/2 | 63.50 | 2.887 | 6.336 |
| 3 | 76.20 | 3.464 | 9.123 |
Supply options
- Lengths
- 3 – 3.66 m (10 – 12 ft) standard; cut pieces and bar-feeder lengths to order
- Metric sizes
- Common spanner sizes (13, 17, 19, 22, 24, 27, 30, 32, 36, 41 mm and up)
- Surface
- Cold-drawn bright or extruded mill finish
Standards and tolerances for 6061 hex bar
Applicable standards
- Cold-finished hex
- ASTM B211 / ASME SB-211; AMS 4117 for aerospace; EN 754-2 (drawn) with EN 754-6 tolerances for hexagonal bar
- Extruded hex
- ASTM B221 / ASME SB-221; AMS 4173 (T6511); EN 755-2 with EN 755-6 tolerances for hexagonal bar
- Tolerance tables
- ANSI H35.2 for ASTM orders
- Designations
- UNS A96061 · EN AW-6061 · Werkstoff 3.3211 · JIS A6061
- Certificate
- EN 10204 3.1 mill test certificate
Machining 6061 hex bar on lathes and screw machines
Chip control
6061-T6 produces short chips but not as short as 2011; use chip-breaking geometries and high-pressure coolant on deep drilling.
Threading
Cuts and rolls good threads. For repeated assembly, consider thread inserts in softer service.
Bar feeding
Choose the collet or guide-tube size from the across-corners dimension, not the across-flats size.
Finishing
Anodise for colour coding and wear resistance; use hard anodising on fittings exposed to abrasion.
Welding
Weldable with ER4043 or ER5356 filler where fittings are welded to tube or plate; the weld zone softens toward T4 strength.
Where 6061 hex bar is used
- Fluid power: hydraulic and pneumatic fittings, adaptors, plugs and manifold connectors
- Fasteners: nuts, bolts, threaded standoffs, spacers and pillars
- Electrical: terminal blocks, connectors and earthing fittings
- Automotive and motorsport: AN-style fittings, adjuster nuts and suspension parts (usually anodised)
- Furniture and architecture: connectors and decorative fixings
- Instruments: sensor housings, tripod and camera fittings
6061 hex compared with 2011, 6082 and 7075 hex
| Alloy | Strength | Machinability | Corrosion resistance | Best for |
|---|---|---|---|---|
| 6061-T6 | Medium | Good | Good | General fittings, anodised parts, outdoor use |
| 2011-T3 | Medium | Excellent (free-cutting) | Fair | High-volume screw-machine parts kept dry |
| 6082-T6 | Medium | Good | Good | European projects specifying EN AW-6082 |
| 7075-T6 / T651 | High | Very good | Fair | Highly loaded nuts and fittings |
How to order 6061 hex bar
- SpecifyAlloy and temper (for example 6061-T6 cold-finished hex, 24 mm A/F), shape and size, length or cut pieces, quantity, and the governing standard (ASTM B211, ASTM B221 or EN 754-2 / 755-2).
- QuoteWe confirm availability, tolerance class, certification and delivery terms (EXW, FOB, CIF or DAP) for your destination.
- ProcessBars are cut to length or to blanks on request, end-marked with alloy, temper and lot number, and inspected for size, straightness and surface.
- DocumentEach shipment carries a mill test certificate to EN 10204 3.1 with chemistry and tensile results, plus the packing list; third-party inspection on request.
- ShipBundles are wrapped and packed in seaworthy wooden cases or on pallets and sent by sea or air to your port or door.
References and standards
- ASTM B211/B211M – Aluminum and Aluminum-Alloy Rolled or Cold Finished Bar, Rod, and Wire
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
- SAE AMS 4173 – 6061-T6511 / T6510 extrusions
- EN 755-6 – Extruded hexagonal bars: tolerances on dimensions and form
- ANSI H35.2 – Dimensional Tolerances for Aluminum Mill Products (The Aluminum Association)
6061 aluminium (aluminum) hex bar: frequently asked questions
How do I calculate the across-corners size of a hex bar?
Multiply the across-flats size by 1.1547. A 24 mm hex measures about 27.7 mm across sharp corners; a 1 in hex about 1.155 in. Real bars have slightly rounded corners, so the measured value is a little smaller.
What is the difference between 6061-T6 and T6511 hex bar?
T6 hex is usually cold-finished, with tighter tolerance and sharper corners. T6511 hex is extruded and stretched for stress relief, so it stays straighter when machined and is available in larger sizes. Strength is essentially the same.
How much does 6061 hex bar weigh?
Weight per metre is 0.002338 × s² kg with s in mm. A 24 mm hex weighs about 1.35 kg/m, and a 1 in hex about 1.01 lb per foot.
Is 6061 hex bar good for threaded fittings?
Yes. It threads cleanly and has good strength in T6. For high-volume dry-service parts, 2011 machines faster; for weather or wet service, 6061 is the better choice because of its corrosion resistance.
Can you cut hex bar to bar-feeder lengths?
Yes. Bars can be cut to the length your bar feeder needs, with ends deburred, and packed to protect the flats in transit.
Need 6061 hex bar?
Send across-flats size, temper, length and quantity. We will reply with availability, certification and a delivered price.
