Reference
Lookup tables for the shop. No calculator needed — just the numbers.
Janka Hardness
The Janka test measures the force (in pounds) required to embed a steel ball halfway into a wood sample. Higher = harder. Use it to compare species for flooring, workbench tops, cutting boards, or any surface that takes abuse. Values are for North American specimens; tropical species can vary by origin.
| Species | Janka (lbf) | Level |
|---|---|---|
| Ipe (Brazilian Walnut) | 3,684 | Very Hard |
| Hickory | 1,820 | Very Hard |
| Maple, Hard | 1,450 | Hard |
| Oak, White | 1,360 | Hard |
| Ash, White | 1,320 | Hard |
| Beech, American | 1,300 | Hard |
| Oak, Red | 1,290 | Hard |
| Birch, Yellow | 1,260 | Hard |
| Teak | 1,070 | Hard |
| Walnut, Black | 1,010 | Hard |
| Cherry, Black | 950 | Hard |
| Pine, Southern Yellow | 870 | Medium |
| Elm, American | 830 | Medium |
| Maple, Soft | 700 | Medium |
| Douglas Fir | 660 | Medium |
| Poplar, Yellow | 540 | Medium |
| Butternut | 490 | Soft |
| Basswood | 410 | Soft |
| Pine, Eastern White | 380 | Soft |
| Cedar, Western Red | 350 | Soft |
Nominal vs. Actual Lumber Sizes
Lumber is sold by nominal size, which is the rough-sawn dimension before drying and surfacing. The actual size you get off the shelf is always smaller. These are standard S4S (surfaced four sides) dimensions.
Softwood Dimensional Lumber
| Nominal | Actual thickness | Actual width |
|---|---|---|
| 1×2 | 3/4″ | 1-1/2″ |
| 1×3 | 3/4″ | 2-1/2″ |
| 1×4 | 3/4″ | 3-1/2″ |
| 1×6 | 3/4″ | 5-1/2″ |
| 1×8 | 3/4″ | 7-1/4″ |
| 1×10 | 3/4″ | 9-1/4″ |
| 1×12 | 3/4″ | 11-1/4″ |
| 2×2 | 1-1/2″ | 1-1/2″ |
| 2×4 | 1-1/2″ | 3-1/2″ |
| 2×6 | 1-1/2″ | 5-1/2″ |
| 2×8 | 1-1/2″ | 7-1/4″ |
| 2×10 | 1-1/2″ | 9-1/4″ |
| 2×12 | 1-1/2″ | 11-1/4″ |
| 4×4 | 3-1/2″ | 3-1/2″ |
| 4×6 | 3-1/2″ | 5-1/2″ |
| 6×6 | 5-1/2″ | 5-1/2″ |
Hardwood — Quarter System
Hardwood is sold by the quarter-inch in rough thickness. After surfacing two sides (S2S) you lose roughly 3/16″. These are typical dressed thicknesses — always measure your actual stock.
| Designation | Nominal (rough) | Typical S2S |
|---|---|---|
| 4/4 | 1″ | 13/16″ |
| 5/4 | 1-1/4″ | 1-1/16″ |
| 6/4 | 1-1/2″ | 1-5/16″ |
| 8/4 | 2″ | 1-13/16″ |
| 10/4 | 2-1/2″ | 2-5/16″ |
| 12/4 | 3″ | 2-13/16″ |
Pilot Hole Sizes
For an interactive lookup by screw size and wood type, use the Pilot Hole Calculator. Full chart below for quick reference.
| Screw | Pilot (softwood) | Pilot (hardwood) | Clearance hole |
|---|---|---|---|
| #2 | 1/16″ 1.6 mm | 1/16″ 1.6 mm | 3/32″ 2.4 mm |
| #4 | 1/16″ 1.6 mm | 5/64″ 2.0 mm | 7/64″ 2.8 mm |
| #6 | 5/64″ 2.0 mm | 3/32″ 2.4 mm | 9/64″ 3.6 mm |
| #8 | 3/32″ 2.4 mm | 7/64″ 2.8 mm | 11/64″ 4.4 mm |
| #10 | 7/64″ 2.8 mm | 1/8″ 3.2 mm | 3/16″ 4.8 mm |
| #12 | 1/8″ 3.2 mm | 9/64″ 3.6 mm | 7/32″ 5.6 mm |
| #14 | 9/64″ 3.6 mm | 11/64″ 4.4 mm | 1/4″ 6.4 mm |