hair lines: Fine lines or incipient checks in the dried surface of finishing materials. Often caused by sudden temperature changes.

hairline: Thin, perceptible lines, usually showing in the joint.

hand rubbed finish: The name given to an effect that is created by the manual process of applying a combination of abrasives and lubricants, after the final topcoat has dried- to smooth, flatten or dull the topcoat.

handrail: A long narrow strip or cylinder of wood used for grasping by hand, as an assistance to maintaining balance and help when climbing up a stair or slope. A banister is one type of handrail.

hard setting: When agitation will not uniform liquid or homogenize.

hardness: The degree a material will withstand pressure without deforming. The property of a coating which causes it to resist denting or penetration by a hard object.

hardwood: Deciduous trees that have broad leaves in contrast to conifers or softwoods. The term has no reference to the actual hardness of the wood.

hardwood dimension lumber: Refers to hardwood lumber processed to a user-specified thickness, width, and length.

haze: The dullness of a surface that prevents a clear reflection of light. Usually caused by partial precipitation of one or more ingredients during the drying period. Only removed by polishing or cleaning.

headrig: The principal saw in a sawmill on which logs are first cut into cants- could be a circular saw or band saw.

heart: The very center of a tree where the pith is. The heartwood of the tree extends from the heart to the sapwood.

heart face: The face grain surface of a plank that is all heartwood.

heartwood: The non living wood extending from the pith to the sapwood,. It is usually darker than the sapwood.

heaving: The slight swelling or raising of the surface caused by partial softening of the undercoat by the solvents in the succeeding coat.

heavy body: A general term denoting a relatively high viscosity in the liquid state or the deposition of a film of great thickness before drying.

heavy coat: A generous or excessive coat of finishing material.

helical: Having the shape of a helix; spiral.

herringbone flooring: A floor pattern produced by laying strips of flooring all the same length in a zigzag pattern that is created by placing the end of one piece into the side of another. The individual pieces must be the exact same length, and are usually cut using a doub

hiding, complete: The ability of a coating to obscure the surface to which it is applied. Hiding power is provided by the paint’s pigment.

high build: A term referring to a finishing agent for which each coat produces a thick layer.

high speed steel: HSS- a grade of steel about 6 times harder than carbon steel and able to retain a cutting edge 5 to 10 times linger than carbon steel.

hit and miss: When a planning operation on a plank results in only some of the planks surface being planed, some of it having skip- it is called hit and miss skip.

hogging: Removing a large amount of wood.

holdout: The ability to prevent the coating from soaking into the substrate.

holiday: A finishing term referring to any bare or thin spot- ( a missed spot).

honeycombing: Internal splitting or collapse, often not visible at the wood surface, that develops as a drying defect . Checks often not visible at the surface that occurring the interior of the piece of wood, usually along the rays.

horsepower: A measurement of power, nominally equal to the pulling strength of one horse, or the power to lift 550 lbs one foot off the ground in one second.

humidity: The common shorthand term for Relative Humidity, which is to say the amount of vaporized moisture in an atmosphere relative to temperature- the amount of water vapor in the air.

hydrophilic: A substance which absorbs or has an affinity for water.

hydrophobic: A substance which neither absorbs or has any affinity for water.

hygrometer: An instrument for measuring the degree of humidity or relative humidity in the atmosphere.

hygroscopic: A substance that can absorb and retain moisture, or lose or throw off moisture. Wood and wood products are hygroscopic. The expand with absorption of moisture and dimensions become smaller when moisture is lost or thrown off.