Hard Maple KD7
Grade
KD7 = 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.
Values for the KD7 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 |
KD12Default 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 |
KD7This page 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 KD7?
Hard Maple KD7 is Hard Maple in the KD7 grade — pick for glued-up worktops, butcher blocks, flooring and machine jigs in heated indoor service where movement must be minimal. Hard Maple KD7 has a tensile strength of 115 MPa (16.7 ksi), stronger than 100% of natural material grades. Elongation at break is 1.3% and the elastic modulus is 13.2 GPa (1.91 Msi). Hard Maple KD7 has a density of 0.68 g/cm³ (0.0246 lb/in³), lighter than 51% of natural material grades. KD12 is the default condition FabDigit quotes; KD7 is available on request or by drawing note.
Advantages
- Polishes to a fine finish — 88/100, better than 94% of natural material grades
Hard Maple KD7 properties
Typical room-temperature values for Hard Maple KD7; 12 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 KD7 has a density of 0.68 g/cm³ (0.0246 lb/in³), lighter than 51% of natural material grades.
Mechanical9
Hard Maple KD7 has a tensile strength of 115 MPa (16.7 ksi), stronger than 100% of natural material grades. Elongation at break is 1.3% and the elastic modulus is 13.2 GPa (1.91 Msi).
Thermal5
Hard Maple KD7 is rated for continuous service to 90°C (194 °F). It conducts heat at 0.15 W/m·K (0.0867 BTU/hr·ft·°F), better than 52% of natural material grades. Thermal expansion is 4.5 µm/m·K (2.5 µin/in·°F).
Electrical1
Hard Maple KD7 has an electrical resistivity of 1×10¹¹ Ω·m.
Chemical & Environmental1
Corrosion resistance is fair (35/100), worse than 66% of natural material grades.
Sustainability4
Producing a kilogram of Hard Maple KD7 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 KD7's machinability is very good (72/100, worse than 60% of natural material grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Hard Maple KD7
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 KD7 — frequently asked
What is Hard Maple KD7 used for?
Hard Maple KD7 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 KD7?
Hard Maple KD7 has a typical tensile strength of 115 MPa (16.7 ksi) — stronger than 100% of natural material grades. Strength varies by condition: see the 3 listed tempers.
Is Hard Maple KD7 easy to machine?
Yes — machinability is rated very good (72/100, worse than 60% 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 KD7 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 KD7?
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 KD7 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 KD7?
Hard Maple KD7 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.