Cherry (Prunus serotina) — Solid Wood Machining
Technical specification for North American Black Cherry solid wood, covering dimensional tolerances, machining parameters, defect identification, and storage protocols for Canadian fabrication and woodworking operations.
Material Overview & Common Uses
North American Black Cherry (Prunus serotina) is a premium domestic hardwood prized for its rich, warm colour that deepens with age, fine texture, and excellent machining properties. It is moderately heavy (specific gravity 0.50–0.55), with a Janka hardness of 950 lbf, making it softer than maple but harder than walnut. Common uses include fine furniture, cabinetry, millwork, architectural joinery, musical instruments, and turned objects. In Canadian shops, cherry is frequently specified for high-end residential and commercial projects where dimensional stability and a smooth, closed-grain finish are required.
Core Technical Properties & Sizing
All values per NHLA grading rules and Canadian lumber standards. MC target: 7 % ±1 % for interior use.
| Parameter | Nominal (Rough) | Net (Planed) | Tolerance |
|---|---|---|---|
| Thickness 4/4 | 1.00″ | 0.75″ | ±0.010″ |
| Thickness 5/4 | 1.25″ | 1.00″ | ±0.010″ |
| Thickness 6/4 | 1.50″ | 1.25″ | ±0.010″ |
| Thickness 8/4 | 2.00″ | 1.75″ | ±0.010″ |
| Width (FAS) | 3″–12″ random | — | ±1/16″ |
| Width (Select & Better) | 3″–8″ random | — | ±1/16″ |
| Length (FAS) | 6′–16′ | cut-to-size | ±1/8″ |
| Length (Common) | 4′–10′ | cut-to-size | ±1/8″ |
| Flatness (max) | — | 1/8″ over 4′ | CNS 3.1 |
| Moisture Content (KD) | 6–8 % | 7 % ±1 % | NHLA Rule |
| Property | Value | Notes |
|---|---|---|
| Shrinkage — Radial | 3.7 % | Low — stable |
| Shrinkage — Tangential | 7.1 % | Low — stable |
| Shrinkage — Volumetric | 11.5 % | Low movement |
| Grain | Fine, straight to slightly wavy | Figure: curly or birdseye (premium) |
| Colour — Heartwood | Light pinkish-brown to rich reddish-brown | Darkens with UV exposure |
| Colour — Sapwood | Narrow (1–2″), pale yellow-white | Contrast reduced with age |
Machinability, Tooling & Feeds
Cherry machines exceptionally well with carbide and HSS tooling. Avoid burnishing — use sharp polished carbide inserts at moderate feed rates.
| Operation | Spindle Speed | Feed Rate | Depth / Pass | Tooling Notes |
|---|---|---|---|---|
| Routing | 8,000–12,000 RPM | 15–25 ft/min | 1/16″ | Carbide, 2–4 passes |
| Shaping | 4,000–6,000 RPM | 10–20 ft/min | 1/16″ | Polished inserts |
| Planing | 4,000–6,000 RPM | 15–25 ft/min | 1/16″ | Sharp carbide; avoid burning |
| CNC — Climb Milling | 18,000 RPM | 200–300 IPM | 1/4″ | 1/2″ compression bit |
| Sanding | — | — | 120–220 grit | Closed-coat stearated; can clog if resinous |
| Process | Recommended Material / Method | Notes |
|---|---|---|
| Gluing | PVA (Titebond II/III) or polyurethane | Avoid excess squeeze-out (stains) |
| Finishing | Oil-based stains, lacquer, shellac, conversion varnish | Use washcoat or gel stain to prevent blotching |
| Pre-finish Sanding | 180 grit | Do not exceed 220 grit for stain adhesion |
Common Defects & Quality Control
Incoming QC per NHLA FAS and Canadian shop standards. Inspect under 5000 K lighting; measure MC with pin meter at 3 points per board.
| Defect Type | Status | Acceptance Criteria / Rejection Threshold |
|---|---|---|
| Pith flecks (medullary rays) | Natural — not a defect | Acceptable in all grades |
| Small sound knots | Acceptable (FAS) | 1–2 per board, max 1/2″ |
| Minor mineral streaks | Acceptable (FAS) | Slight variation only |
| Open knots | Rejectable | Any open knot on face |
| Bark pockets | Rejectable | Any bark on face |
| Wane (bark edge) | Rejectable | Exceeding 1/8″ on face |
| Checks (end or surface) | Rejectable | Longer than 1/4″ |
| Twist or cup | Rejectable | Exceeding 1/4″ over 4′ |
| Insect damage (pinholes, wormholes) | Rejectable | Any evidence |
| Blue stain (fungal) | Rejectable | Any visible stain |
| Excessive sapwood | Rejectable (FAS) | Over 20 % of board |
| Moisture content | Rejectable | >9 % at any measurement point |
CNC blank flatness check: 0.005″/ft max deviation on granite plate. Reject if exceeded.
Storage, Handling & Racking Guidelines
Store cherry in a climate-controlled environment (65–75 °F, 35–45 % RH) to maintain 6–8 % MC. Rack on 4″×4″ stickers spaced 24″ apart, with boards stacked flat and aligned. Do not store directly on concrete — use 2×4 sleepers with vapour barrier. For long-term storage (over 30 days), wrap bundles in breathable plastic (e.g., Tyvek) to prevent dust accumulation while allowing moisture exchange. Handle with clean gloves to avoid oil/sweat stains. FIFO rotation: use oldest stock first. For CNC blanks, pre-condition in shop environment for 72 hours before machining. Do not store near heat sources or in direct sunlight (accelerates colour change and checking).