L
ASTM D709 Grade L, D709 Type L · GB 5021
L is a fine-weave cotton-fabric phenolic laminate to ASTM D709 Grade L, also listed as grade 5021 and PF CL 201 (IEC 60893), and is the mechanical member of the cotton-phenolic family.
Reference datasheet — L is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the L condition
L grades and fills
L is supplied in 5 conditions, soft to hard. L is the default FabDigit quotes; the values on this page are for it.
Compare all 5 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
L + MoS2/graphite | Use for unlubricated or marginally lubricated bushings, thrust washers and slide blocks where friction and stick-slip must be minimised. | 85 | 1.6 | 105 HRM | |
L, oil-impregnated | Oil-impregnated fine-weave phenolic for water-lubricated or oil-fed bearings such as rolling-mill and pump bushings. | 85 | 1.7 | 100 HRM | |
L, flame-retardant modified | FR-modified cotton phenolic for enclosure and switchgear parts needing a UL 94 V-0 rating. | 88 | 1.7 | 106 HRM | |
Fine-weave cotton fabric phenolic, electrical grade | Pick when the same machined cotton-phenolic part must also insulate at power frequency in dry conditions. | 90 | 1.7 | 105 HRM | |
LDefault Fine-weave cotton fabric phenolic, mechanical grade | Standard choice for machined gears, bushings, wear pads and jigs where fine surface finish and dimensional stability matter more than electrical properties. | 95 | 1.8 | 108 HRM |
Supply forms, finishes and certifications
Ways L is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
L-ROD | L | Supply form |
What is L?
L is a fine-weave cotton-fabric phenolic laminate to ASTM D709 Grade L, also listed as grade 5021 and PF CL 201 (IEC 60893), and is the mechanical member of the cotton-phenolic family. The fine weave supports crisp gear teeth and close-tolerance turned parts, and it is supplied as pressed sheet, rolled tube and rod, including MoS2-filled, oil-filled and flame-retardant conditions. Tensile strength is about 95 MPa with service to roughly 120 °C and a machinability score of 80. It is not weldable, machined edges pick up moisture, and its insulation is mechanical-grade only — Grade LE is the electrical version. L has a density of 1.36 g/cm³ (0.0491 lb/in³), lighter than 70% of composite grades. Its glass-transition temperature is 155°C (311 °F). L has a tensile strength of 95 MPa (13.8 ksi), weaker than 69% of composite grades. Elongation at break is 1.8% and the elastic modulus is 7.5 GPa (1.09 Msi).
What is L used for?
- precision gears
- bushings
- rollers
- cam followers
Advantages
- Easy to machine — 80/100, better than 85% of composite grades
Limitations
- Low fracture toughness — 2 MPa·√m (1.82 ksi·√in), worse than 87% of composite grades
- Needs corrosion protection — 55/100, worse than 87% of composite grades
- Limited service temperature — 120°C (248 °F), worse than 78% of composite grades
- Absorbs moisture — dry before molding — 1.4%, worse than 78% of composite grades
L properties
Typical room-temperature values for L-L; bars are the position among composite grades.
Physical4
L has a density of 1.36 g/cm³ (0.0491 lb/in³), lighter than 70% of composite grades. Its glass-transition temperature is 155°C (311 °F).
Mechanical14
L has a tensile strength of 95 MPa (13.8 ksi), weaker than 69% of composite grades. Elongation at break is 1.8% and the elastic modulus is 7.5 GPa (1.09 Msi).
Thermal9
L is rated for continuous service to 120°C (248 °F). It conducts heat at 0.3 W/m·K (0.173 BTU/hr·ft·°F), worse than 63% of composite grades. Thermal expansion is 25 µm/m·K (13.9 µin/in·°F).
Electrical7
L is an electrical insulator with a dielectric strength of 10 kV/mm (254 V/mil) and a resistivity of 1×10⁹ Ω·m.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 87% of composite grades. UV resistance is fair.
Sustainability3
Producing a kilogram of L takes about 90 MJ of energy and emits 4.6 kg of CO₂ — less than 75% of composite grades. Typical recycled content is 0%.
Manufacturability2
L's machinability is very good (80/100, better than 85% of composite grades).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the composite family
Yield strength against density for every composite grade FabDigit runs. L is highlighted; hover a dot for its name, or open the interactive family chart.
Working with L
Is L easy to machine?
Machines readily with sharp carbide or PCD tooling at high speed and low feed; dust is abrasive and irritating, so use extraction and avoid heat build-up that scorches the resin.
Can L be welded?
Thermoset — cannot be welded or heat-formed; join by bolting, riveting, pinning or epoxy bonding after abrading the surface.
Can L be formed, bent or molded?
Supplied as fully cured pressed sheet, rolled tube or rod; shape only by cutting/machining, and pre-drill before tapping to avoid delamination or edge chipping.
L chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| cotton fabric (fine weave, plain/twill)reinforcement, typically 100–160 g/m² fine-weave cloth | 45 – 60 | 55 |
| residual volatiles / moisture | 0 – 2 | 1 |
| phenol-formaldehyde (resol) resinmatrix, cured under heat and pressure | ≥ 38 (balance) |
What surface finishes work on L?
Cannot be plated or anodised; edges are usually sealed with varnish, epoxy or oil to limit moisture pick-up, and surfaces can be sanded and lightly polished to a matte dark-brown finish.
Equivalent designations
Standards and trade names that resolve to L in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- D709 Grade LD709 Type L
- GB (China)
- 5021
- Also called
- NEMA L
How much does L cost?
L is a premium-cost composite ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
L — frequently asked
What is L used for?
L is typically used for precision gears, bushings, rollers and cam followers. In short: fine-weave mechanical cotton phenolic; quiet-running gear material; moS2 and oil-filled options.
What is the tensile strength of L?
L has a typical tensile strength of 95 MPa (13.8 ksi) — weaker than 69% of composite grades. Strength varies by condition: see the 5 listed tempers.
Is L easy to machine?
Yes — machinability is rated very good (80/100, better than 85% of composite grades). Machines readily with sharp carbide or PCD tooling at high speed and low feed; dust is abrasive and irritating, so use extraction and avoid heat build-up that scorches the resin.
Can L be welded?
Thermoset — cannot be welded or heat-formed; join by bolting, riveting, pinning or epoxy bonding after abrading the surface.
What surface finishes work on L?
Cannot be plated or anodised; edges are usually sealed with varnish, epoxy or oil to limit moisture pick-up, and surfaces can be sanded and lightly polished to a matte dark-brown finish.
Can L be formed, bent or molded?
Supplied as fully cured pressed sheet, rolled tube or rod; shape only by cutting/machining, and pre-drill before tapping to avoid delamination or edge chipping.
What is the maximum service temperature of L?
L is rated for continuous use to about 120°C (248 °F), and briefly to 150°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does L cost?
L is a premium-cost composite ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM D709 Standard Specification for Laminated Thermosetting Materials — ASTM International (2017)
- NEMA LI 1 Industrial Laminating Thermosetting Products — NEMA (1998)
- IEC 60893-3-4 Insulating materials — Industrial rigid laminated sheets — Phenolic cellulose (PF CL/CC/CP) — IEC (2013)
- Cotton fabric phenolic laminate (Grade L/LE) datasheets — Various laminate producers (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.