Hard Maple KD12
Finish state · default condition
KD12 = kiln-dried / air-dried to 12 % MC
Default engineering condition: lumber equilibrated near 12 % MC, matching all published design and clear-wood strength tables.
Values for the KD12 condition
Other Hard Maple tempers and conditions
Hard Maple is listed in 3 conditions; see the grade overview at Hard Maple.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Freshly sawn, MC above fibre saturation | Pick for steam-bending, wet turning or when the part will be dried after shaping; strength is roughly half of dry. | — | 70 | 2 | — | 0.3 W/m·K |
KD12DefaultThis page Kiln-dried / air-dried to 12 % MC | Default engineering condition: lumber equilibrated near 12 % MC, matching all published design and clear-wood strength tables. | — | 108 | 1.5 | — | 0.16 W/m·K |
Kiln-dried to 6–8 % MC | Pick for glued-up worktops, butcher blocks, flooring and machine jigs in heated indoor service where movement must be minimal. | — | 115 | 1.3 | — | 0.15 W/m·K |
What is Hard Maple KD12?
Hard Maple KD12 is Hard Maple supplied in the KD12 condition — default engineering condition: lumber equilibrated near 12 % MC, matching all published design and clear-wood strength tables. Hard Maple KD12 has a tensile strength of 108 MPa (15.7 ksi), stronger than 94% of natural material grades. Elongation at break is 1.5% and the elastic modulus is 12.6 GPa (1.83 Msi). Hard Maple KD12 has a density of 0.7 g/cm³ (0.0253 lb/in³), heavier than 53% of natural material grades.
Advantages
- Polishes to a fine finish — 85/100, better than 87% of natural material grades
Limitations
- Needs corrosion protection — 30/100, worse than 77% of natural material grades
Hard Maple KD12 properties
Typical room-temperature values for Hard Maple KD12; 11 are specific to this condition. Other listed values are Hard Maple reference data and may not represent this condition. Bars are the position among natural material grades.
Physical2
Hard Maple KD12 has a density of 0.7 g/cm³ (0.0253 lb/in³), heavier than 53% of natural material grades.
Mechanical9
Hard Maple KD12 has a tensile strength of 108 MPa (15.7 ksi), stronger than 94% of natural material grades. Elongation at break is 1.5% and the elastic modulus is 12.6 GPa (1.83 Msi).
Thermal5
Hard Maple KD12 is rated for continuous service to 90°C (194 °F). It conducts heat at 0.16 W/m·K (0.0924 BTU/hr·ft·°F), better than 64% of natural material grades. Thermal expansion is 4.5 µm/m·K (2.5 µin/in·°F).
Electrical1
Hard Maple KD12 has an electrical resistivity of 1×10⁹ Ω·m.
Chemical & Environmental1
Corrosion resistance is poor (30/100), worse than 77% of natural material grades.
Sustainability4
Producing a kilogram of Hard Maple KD12 takes about 12 MJ of energy and emits 0.55 kg of CO₂ — more than 69% of natural material grades. Typical recycled content is 0%.
Manufacturability2
Hard Maple KD12's machinability is very good (70/100, worse than 67% of natural material grades).
Common Calculations4
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Hard Maple KD12
Is Hard Maple easy to machine?
Cuts cleanly with carbide at moderate feed rates but burns easily on stationary cuts and dulls HSS quickly — use sharp tooling, climb-limited feeds and good chip evacuation.
Can Hard Maple be welded?
Not weldable; joined by PVAc/PU/epoxy adhesives or mechanical fasteners — pre-drill for screws to avoid splitting.
Can Hard Maple be formed, bent or molded?
Bends fairly well when steamed or after ammonia/hot-water plasticising at green to 20 % MC; account for ~9–10 % tangential and ~5 % radial shrinkage when drying.
What surface finishes work on Hard Maple?
Fine closed grain sands to a very smooth surface and takes clear lacquer, oil-wax or hardwax well; it blotches with pigmented stains, so use a washcoat or dye, and keep out of persistently damp service.
Hard Maple 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 |
|---|---|---|
| celluloseoven-dry basis | 42 – 48 | 45 |
| hemicellulosemainly glucuronoxylan | 25 – 33 | 30 |
| ligninsyringyl-rich hardwood lignin | 20 – 25 | 22 |
| extractivessugars, phenolics — low decay resistance | 1 – 4 | 2.5 |
| ash | 0.2 – 0.5 | 0.3 |
| moistureservice MC; reference tables at 12 % | ≥ 6 (balance) | — |
Hard Maple KD12 — frequently asked
What is Hard Maple KD12 used for?
Hard Maple KD12 is typically used for flooring, cutting boards, furniture, musical instruments and bowling lanes. In short: most wear-resistant domestic hardwood; closed grain, very smooth finish; low decay resistance when damp.
What is the tensile strength of Hard Maple KD12?
Hard Maple KD12 has a typical tensile strength of 108 MPa (15.7 ksi) — stronger than 94% of natural material grades. Strength varies by condition: see the 3 listed tempers.
Is Hard Maple KD12 easy to machine?
Yes — machinability is rated very good (70/100, worse than 67% of natural material grades). Cuts cleanly with carbide at moderate feed rates but burns easily on stationary cuts and dulls HSS quickly — use sharp tooling, climb-limited feeds and good chip evacuation.
Can Hard Maple KD12 be welded?
Not weldable; joined by PVAc/PU/epoxy adhesives or mechanical fasteners — pre-drill for screws to avoid splitting.
What surface finishes work on Hard Maple KD12?
Fine closed grain sands to a very smooth surface and takes clear lacquer, oil-wax or hardwax well; it blotches with pigmented stains, so use a washcoat or dye, and keep out of persistently damp service.
Can Hard Maple KD12 be formed, bent or molded?
Bends fairly well when steamed or after ammonia/hot-water plasticising at green to 20 % MC; account for ~9–10 % tangential and ~5 % radial shrinkage when drying.
What is the maximum service temperature of Hard Maple KD12?
Hard Maple KD12 is rated for continuous use to about 90°C (194 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- Wood Handbook — Wood as an Engineering Material, FPL-GTR-282, Ch. 5 Mechanical Properties — USDA Forest Service, Forest Products Laboratory (2021)
- ASTM D143 — Standard Test Methods for Small Clear Specimens of Timber — ASTM International (2022)
- ASTM D2555 — Establishing Clear Wood Strength Values — ASTM International (2017)
- NHLA Rules for the Measurement and Inspection of Hardwood and Cypress — National Hardwood Lumber Association (2023)
- CES EduPack / ICE embodied-energy data for kiln-dried hardwood — Granta Design / University of Bath (2019)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.