Hardwood Lumber Grades for Epoxy Tables: NHLA System Guide

Understanding NHLA Hardwood Lumber Grades

When selecting hardwood lumber for an epoxy river table, a solid tabletop, or a sturdy base, buying boards by the grade ensures you purchase the right material without unnecessary waste. Hardwood lumber in the United States is graded under the rules of the National Hardwood Lumber Association (NHLA), as detailed in the Wood Handbook (General Technical Report FPL-GTR-282) published by the USDA Forest Products Laboratory.

Unlike softwood framing lumber, which is graded based on the structural strength of an entire board, hardwood grading is based on the proportion of clear, usable wood that can be obtained by cutting the piece into smaller sections known as clear-face cuttings. Standard hardwood lumber is typically sawn to random widths, with standard lengths offered in 1-ft (305-mm) increments ranging from 4 to 16 ft (1.2 to 4.9 m). As a standard rule, hardwood inspection is conducted on the poorer side of the board, except in the Selects grade where inspection takes place from the better face.

Top Grades for Tabletop Surfaces: FAS, F1F, and Selects

Tabletops require expansive, defect-free areas or clear wood banks alongside an epoxy river. For these critical visible surfaces, upper-grade lumber provides the highest yield of large, clear cuttings.

• FAS (Firsts and Seconds): FAS represents the premium hardwood grade. It requires a minimum board width of 6 in. (152 mm) and lengths from 8 to 16 ft. In FAS, boards must yield between 83-1/3% and 91-2/3% clear-face cuttings depending on surface measure, with minimum cutting sizes of 4 in. by 5 ft or 3 in. by 7 ft. This grade is best suited for wide tabletop slabs, long seamless edges, and wide wood banks where large expanses without knots or blemishes are necessary.
• F1F (FAS One Face): F1F requires boards to meet FAS standards on the better face, while the reverse side must grade not below No. 1 Common. Like FAS, F1F requires a minimum width of 6 in. (152 mm) and lengths of 8 to 16 ft. Because epoxy tabletops have an upward-facing display side and an underside that is hidden or less visible, F1F offers an efficient choice without sacrificing top-surface appearance.
• Selects: Selects boards have a minimum width of 4 in. (102 mm) and lengths from 6 to 16 ft. For surface measures of 2 and 3 ft2, Selects requires 91-2/3% clear-face cuttings in minimum cutting sizes of 4 in. by 5 ft or 3 in. by 7 ft. For surface measures of 4 ft2 and higher, the board must meet F1F requirements, with the reverse face grading not below No. 1 Common. Selects works well for narrower tabletop surfaces, bookmatched river banks, and perimeter borders.

Grades for Bases, Legs, and Stretchers: No. 1 Common

Table bases, aprons, and legs do not demand the huge, single-piece cutting sizes required by a tabletop. For these structural components, No. 1 Common is often the most economical and practical grade.

No. 1 Common allows boards with a minimum width of 3 in. (76 mm) and lengths from 4 to 16 ft (with only 5% of minimum width allowed). Boards yield between 66-2/3% and 100% clear-face cuttings, with a smaller minimum cutting size of 4 in. by 2 ft or 3 in. by 3 ft. Because table legs, rails, and stretchers are shorter and narrower than tabletops, shop builders can easily break down No. 1 Common boards into clean, clear component parts while avoiding unwanted defects.

Grades for Small Parts, Cleats, and Character Work: No. 2 Common and Lower

Lower lumber grades yield smaller clear cuttings or admit natural characteristics:

• No. 2 Common: Minimum width of 3 in. (76 mm) and lengths from 4 to 16 ft. Clear-face cutting yield ranges between 50% and 66-2/3%, with a minimum cutting size of 3 in. by 2 ft. This grade is well suited for small internal braces, corner blocks, mounting cleats, and short sub-assemblies.
• No. 3A and No. 3B Common: No. 3A Common yields 33-1/3% clear cuttings with a 3 in. by 2 ft minimum cutting size (or grades not below No. 2 Common on the good face and reverse side of sound cuttings). No. 3B Common yields 25% sound cuttings where clear face is not required, down to a minimum cutting size of 1-1/2 in. by 36 in2. Cuttings in both grades are unlimited in number.
• Sound Wormy: This grade admits natural characteristics including worm holes, bird pecks, stain, and sound knots not exceeding 3/4 in. in diameter. Pieces must not grade below No. 1 Common apart from these admitted sound characteristics, making it useful for rustic designs where epoxy fills voids and worm channels.

Shop Lumber Selection Checklist

1. Identify the component role: Plan FAS or F1F for primary top surfaces, No. 1 Common for legs and aprons, and No. 2 Common for cleats and mounting blocks.
2. Check minimum board widths: Verify that FAS and F1F lumber measures at least 6 in. wide, Selects measures at least 4 in. wide, and Common grades measure at least 3 in. wide.
3. Calculate cutting sizes: Ensure required tabletop parts can be cut from standard minimum cutting sizes (such as 4 in. by 5 ft or 3 in. by 7 ft for FAS, and 4 in. by 2 ft or 3 in. by 3 ft for No. 1 Common).
4. Inspect both faces: Remember that FAS and Common grades are evaluated on the poorer face, whereas Selects evaluates the better face with a No. 1 Common reverse.

Sources

• USDA Forest Products Laboratory, Wood Handbook (FPL-GTR-282, 2021)

Published October 29, 2026. Sources are linked in the text.

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