The HobbitHouse Ilustrated Glossary of Woodworking terms

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I beam --- A beam that has strips added along both upper and lower edges so that the whole thing has the cross section of the letter "I". The horizontal elements are called flanges and the vertical element is the web. It is common in wooden construction to have I beams that have composite material as the web with solid wood planks as the flanges. I beams provide strength against flexing in any direction, as opposed to regular beams which provide relatively little strength against flexing perpendicular to their flat surface (the web part of an I beam). I beams are always mounted with the web vertical and the flanges horizontal and tend to have greater strength to weight ratio than planks (which is what was used for floor joists, for example, prior to the advent of composite material I beams). Examples:

ice dam --- Ice that occurs When a snow load melts on a roof and re-freezes at the eave areas, forcing water back up into the roofs and causing leakage. Ice dams are very bad things. In many Northern localities, long horizontal strips of sheet metal, a foot or two wide, are placed along the lower portion of roofs to help prevent them.

ID --- Inner Diameter. Compare/contrast to OD

I joist --- synonymous with I beam

immiscible --- Describes a liquid that does not work and play well with other liquids; incapable of being mixed. Technically, the term also applies to all fluids including gasses, but it's usually used regarding liquids. Antonym is miscible

impact bending --- In the impact bending test, a hammer of given weight is dropped onto a wooden beam from successively increased heights until the beam either deflects 6" or more, or ruptures entirely. The height of that maximum drop gives a comparative value of impact resistance for different species and/or different beam construction techniques.

impact resistance --- The ability of a structural framing member to resist deformation or cracking due to a forceful blow.

impact strength --- see impact resistance

impermeable --- The degree to which a substance blocks fluids from coming into it. The terms is most relevant regarding wood when discussing the degree to which the heartwood or sapwood of a given species does or does not allow the entrance of preservative liquids. There are two effects of a wood being highly impermeable. First, it makes the wood good for tight cooperage and second, it is difficult to impossible to treat such wood with preservative treatments. Contrast to permeable. NOTE: in standard English, the term nonporous has as one of its meanings something very like impermeable, but as regards wood, the term should not be used that way (it IS anyway, a common error).

inboard --- see inboard turning

inboard bowl scraper --- synonymous with bowl scraper. That is, the "normal" bowl scraper is what is otherwise also called an "inboard bowl scraper" to distinguish it from the similar outboard bowl scraper. See also inboard turning.

inboard turning --- When an object is turned on a lathe for face turning the rotation is normally counterclockwise as seen looking into the headstock, so the tool rest is placed on the left side of the object being turned and the left side of the lathe tool cuts into the object as it moves down past the tool rest. This is called inboard turning. When it is necessary to turn the rear of an object that is mounted for face turning, then the object is moving in a clockwise direction as you look at it from the rear, and the cutting edge of the lathe tool has to be on the right side of the tool, for what is called outboard turning. Some lathe tools (e.g. bowl gouges), this doesn't matter because the tools have cutting edges on both sides and so can be used either way. Some tools however (e.g. bowl scrapers, have the cutting edge on the side and there have to be separate versions for inboard and outboard turning. Compare/contrast to outboard turning.

in-cannel --- The characteristic of a gouge that has its ground and sharpened end section on the inside of the blade. In-cannel blades are used to carve or turn concave surfaces. Compare/contrast to out-cannel. Examples (actually these are all the same gouge drawing, just seen from different angles):

incipient decay --- The early stage of decay that has not proceeded far enough to soften or otherwise perceptibly impair the hardness of the wood. It is usually accompanied by a slight discoloration or bleaching.

incline --- synonymous with pitch

inclined plane --- One of the 6 simple machines of classical mechanics, the inclined plane is, as the name suggests, just a flat surface (a plane, in geometric terms) that is inclined (that is angled) relative to a reference plane (typically a horizontal surface). The angle and length of the inclined plane can be used to provide mechanical advantage to trade distance for force. For example, an inclined plane at an angle of 26 degrees has a mechanical advantage of 2:1, so you could roll a 200lb barrel up such a plane with only 100lbs of force (moving the barrel upwards by one foot for every 2 feet that you pushed it forward).

incompatible --- Unsuitable for use together because of undesirable chemical or physical effects. Often used in reference to finishing agents which are not capable of being mixed with one another.

inconspicuous --- As regards woodworking, this refers to defects that are barely detectable with the naked eye at a distance of 6 feet to 8 feet.

increment borer --- An auger-like tool with a hollow bit designed to extract cores from tree stems for the determination of age and growth rate.

indented grain --- A section of grain that is indented from the grain line of which it is a part. There really are two notably different forms of indented grain. The first is what I personally refer to as "normal" indented grain, as discussed in Bruce Hoadley's "Identifying Wood" on page 65 where he specifically states that it is the cause of bear claw figure. This type of indented grain occurs in softwoods such as spruce and pine. Then there is the kind of indented grain that I call, for obvious reasons, "spiky" indented grain. It has spikes running through the grain lines, which are moved off of the straight and narrow by the spikes, but in a more triangular way than the "normal" indentations which are rectangular. This kind of indented grain occurs in hardwoods such as maple. Examples:

independent jaw chuck --- A type of chuck where each jaw is controlled independently rather than all being controlled together as in a scroll chuck. It can be a 3 jaw or 4 jaw chuck (or even more). There are three advantages to this type of chuck over a selfcentering chuck such as the scroll chuck. The first is that the centering can be fine tuned to minimize runout, the second is that it can hold irregular shaped objects, and the third is that it allows for off-center turning. The disadvantage of this type of chuck is that it HAS to be adjusted for centering, which makes it more time consuming to use than a self centering chuck. When looking at a chuck it is immediately apparent whether it is a scroll chuck or an independent jaw chuck because unlike the scroll chuck which has only one adjustment hole, the independent jaw chuck has an adjustment hole with every jaw. Examples:

index head --- synonymous with index plate

index plate --- A plate used to lock a tool's drive-shaft into a series of pre-set regular positions. An index plate on a lathe, for example, provides a way to hold a spindle in several regularly-spaced positions to allow a lengthwise operation to be performed on it from the top or side.

industrial hinge --- A heavy-duty architectural hinge for use in public places where doors are subjected to much heavier use than are doors in residential settings which use lighter-duty versions of architectural hinges called "residential hinges".

inert --- In English, it means not moving or acting, or not able to move or act, chemically inactive; as regard woodworking it generally refers to portions of finishing agents which are stable (non-reactive).

infeed --- (1)[noun] The direction a workpiece is fed into a blade or cutter.
infeed --- (2)[noun] The area into which a workpiece is fed into a blade or cutter.
infeed --- (3)[verb] The process of feeding a workpiece into a blade or cutter.

Infeed direction should always go against the direction of travel of the cutting edge into which the wood is being fed, otherwise the edge could grab the wood and whip it through the mechanism in an uncontrolled manner. I know this well from first hand experience because I once (VERY early in my woodworking experience) fed a two-by-four into a radial arm saw in the direction of blade spin and the blade grabbed the 2x4 and rode up over it as it whipped it along the saw bed, threw it across the room and smashed it into the drywall on the other side of the basement where I was performing this inanity. I was lucky in that I was several feet from the blade, so the 2x4 didn't carry my hands into the blade. This was a REALLY good lesson for me, but not something that I recommend taking up as a hobby. Contrast to outfeed.

inlay --- [noun] Decorative inserts. In woodworking, this is normally small strips of intricate wood patterns in a strip that is inserted into shallow grooves in a larger wood surface for the purpose of creating a decorative effect, but it CAN be an insertion of metal, stone, or other materials for the same purpose. There are manufactured strips of wood inlay that are readily available for such use. Compare/contrast to marquetry and parquetry.
inlay --- [verb] to create an inlay (see [noun] above)

inner plies --- In construction of panels made of composite material such as plywood, all plies other than face or back plies are called inner plies. See also core.

inorganic --- Refers to compounds that do not contain carbon; compounds that are not alive now and never have been. Compare/contrast to organic.

insect attack --- There are all kinds of little critters that like to lunch on wood, and many that also use it as a nesting place for their larvae. They can cause damage in wood that ranges from minor to catastrophic. Some of these are: NOTE: INCOMPLETE SECTION --- most terms below are not yet defined

insect damage --- see insect attack

insect engravings --- The tracks left in the outer sapwood by insects and larvae which feed on the cambium (and in the process eat away some of the inner bark and outer sapwood); when the bark is stripped off after such attacks, the outer sapwood shows tracks that are called "insect engravings" or "worm tracks". Example of insect engravings in a persimmon turning block:

insert nut --- synonymous with threaded insert

inset bead --- A bead which is surrounded by wood that is more or less flush with the top of the bead. See the term bead for illustrations. Compare/contrast to standing bead.

inset door --- see face frame door

inset face frame door --- see face frame door

inshave --- As nearly as I can determine, this is a little-used term that is synonymous with drawknife and since drawknives include spoke shaves and scorps, they are also sometimes referred to as inshaves.

insoluble --- Not capable of being dissolved in a liquid. Sometimes used in reference to a specific liquid, as in "This power is water insoluble" although more normal grammar would be to use the phrase "This power is not water soluble". Substances can be insoluble in some liquids but soluble in others. Compare/contrast to soluble.

insulated --- Protected by some form of insulation from the undesirable flow of heat or electricity.

insulation --- A material that prevents the undesirable flow of something such as heat or electricity. Heat and electricity are often good things but having a lot of electricity flow through your body is not generally a good thing and having a lot of your expensively generated heat flow out of your house in the winter is also not a good thing. SO ... there are lots of materials and construction techniques that have been designed specifically to prevent such occurrences. Things such as power tools that have electricity inside have wires covered with a non-conducting material such as plastic or rubber so that the electricity STAYS inside, and house walls have material such as fiberglass or styrofoam in the walls to keeps the heat inside.

intarsia --- In woodworking, this is a form of wood inlaying that is similar to marquetry but which uses somewhat thicker wood than the veneer that is used in marquetry. The technique of intarsia inlays sections of wood to build up an image, the colors of which are the natural colors of the wood. Since the woods used are not flat like veneer, intarsia images have a 3D look. Below is an intarsia work by Mr. LaVerne Teaney. I ran across his work some years ago at a woodworking show in upstate New York and was impressed enough to take some pics. On the left is the largest piece he had on display at the show and to the right are a couple of closeups of it. Like marquetry, intarsia, including Mr Teaney's work, often is much more colorful than this example, making good use of a wide range of colors and grains.

intergrown knot --- A type of knot where the rings of annual growth of the knot are completely intergrown with those of the surrounding wood. Such knots are formed when trees grow around the base of a branch as the tree trunk expands. There is no implication in this term as to the state of the knot, except at its edges. That is, an intergrown knot will not fall out of the plank that it is in, but it could have cracks and voids. Compare/contrast to encased knot. Examples:

interior glue --- Specifically, this refers to moisture-resistant, but not waterproof, adhesive used in the manufacture of plywood panels that are designated for indoor use, but by extension it refers to any glue designed for use on indoor constructions whether it is cabinetry or framing.

interior grade plywood --- This is the "normal" version of plywood, created for interior use with an adhesive that is NOT waterproof. This plywood can withstand only temporary exposure to moisture. Compare/contrast to exterior grade plywood.

interior panel --- A plywood or other composite material panel made with glue that is not waterproof; intended for interior applications only. Compare/contrast to exterior panel.

interlayment --- A particular form of loose overlapping underlayment sheets used with shake roofs.

interlocked --- A term used to describe the grain in wood where the tree fibers have twisted during growth, resulting in a spiral orientation of the fibers up the trunk rather that the normal situation where the fibers run parallel to the centerline of the tree. When this spiral changes direction from year to year (or in groups of multiple years), the result is what is called "interlocked" grain and it is the primary reason for such figures as "ribbon stripe" (in quartersawn stock), "mottled", "curly", "fiddleback" (an extreme case of curly) and others. It also is frequently accompanied by a more shiny surface than is otherwise the case for non-interlocked samples of the same species and can cause the wood surface to have a high chatoyancy. It occurs in many hardwoods, and although it often produces a visually stunning figure, such woods can be difficult to work because the interlocked grain tends to tear out in planing and other operations. Also, such wood is exceedingly difficult to split radially, though tangentially it may split fairly easily. I have not been able to find any explanation as to WHY the grain direction changes nor does there seem to be any definitive information on how OFTEN it changes. If anyone can point me at any authoritative sources on either of those topics, I would be grateful. Here is a drawing showing interlocked grain in 3 periods of a tree's growth (the times for each direction apparently may be one or more years):

interlocking joint --- A joint where each piece is cut to fit into another to prevent displacement and to transfer forces. A tabled scarf joint is a good example of an interlocking joint.

interlocking miter joint --- A complex joint that does not appear to me to be worth the rather extraordinary effort that it would take to create. Best illustrated by example, so here you go:

interlocking mortise and tenon --- see interlocking tenon

interlocking tenon --- This name is used for two fundamentally different joints. The first is a 3-way joint where the interlocking is necessary to allow all three parts to fit together and the second is a technique used in a standard mortise and tenon joint in which one of the tenons interlocks with the other one to provide extra strength against pullout. There are numerous types of the second kind of interlocking techniques. Here's the first type of joint and two of the more common ones of the second type:

internal-external tooth lock washer --- A lock washer for which the locking mechanism is a set of teeth around the inner rim and another around the outer rim of what would otherwise be a flat washer. This type has the same disadvantage as the external tooth lock washer in that it will mar the surface (of the object being clamped) where it shows, but this type has the greatest locking power of the toothed-type lock washers. Examples:

internal-external washer --- synonymous with internal-external tooth lock washer

internal stress --- Stress that exists within a piece of lumber even in the absence of applied external forces. case hardening is one form of internal stress.

internal tooth lock washer --- A lock washer for which the locking mechanism is a set of teeth around the inner rim of what would otherwise be a flat washer. This type, as contrasted to an external tooth lock washer, has less holding power, but will not mar the surface (of the object being clamped) where it shows. Examples:

interpolate --- To estimate a value that falls between known values. As a simple example, suppose you have a ruler that is marked in 1/10" increments but you want a measurement that is, as closely as you can get it, good to 1/100". If the thing you are measuring is just over halfway between 9.2" and 9.3" then you would likely interpolate the reading as 9.26".

interrupted cut --- The action of a lathe tool when it is cutting a non-yet-round object on a lathe; the tool is cutting wood during some of the workpiece's revolution but just sitting in the air for part of the revolution. Tools are harder to control during interrupted cuts than in full cut work, and care must be taken during interrupted cuts to avoid causing chip-out.

introduced species --- A non-native species that was intentionally or unintentionally brought into an area by humans. Many trees grow well in areas where they are introduced species, others do not.

intumescent coating --- A type of fire retardant coating which, when heated, produces nonflammable gasses which are trapped by the film, converting it to a foam, thereby insulating the material underneath.

invisible hinge --- synonymous with fully concealed hinge

involute curve --- Technically, this is the curve traced by a point on a taut, inextensible string as it unwinds from another curve, but in terms of woodworking, this is pretty much confined to the specific curve traced out by unwinding a string from a cylinder. This particular form of spiral curve is known as a "logarithmic spiral" and it is what you see on a snail's shell, and in huge numbers of other places in nature. Cams are generally made with involute curves as this is a very effective shape for them.

Irish grind --- synonymous with fingernail grind

ironmongery --- A general name for all articles made of iron.

irregular grain --- Wood grain lines that swirl or curve in an abnormal way. This term can include grain that is, for example, swirly due to being near a crotch or a knot or the stump or it could be a burl or just grain that is abnormal due to abnormalities or flaws in the tree (such as the "special etimoe" shown in the composite pic below). There are some specific types, such as wavy grain (aka "swirly grain"), that are considered "irregular" but are so common that they also have specific designations. Examples:

irregular growth --- (1) Term used to describe many small trees and large bushes (that are big enough to produce wood of interest to woodworkers) that grow with erratic trunks that, rather than being the normal cylindrical shape of most tree trunks, bend and twist.
irregular growth --- (2) Term used to describe various defects including:

isometric drawing --- A scale drawing in which lines that are parallel in reality are shown as parallel but due to the inclined view, tend to give a slight impression of perspective. Isometric drawings do not convey the sense of realism found in perspective drawings, but they are more amenable to the conveyance of technical information. Not surprisingly, isometric drawings are used in engineering and technical drawings, whereas perspective drawings are used in artwork where realism is desired. In woodworking, one normally uses isometric drawings. Compare/contrast to perspective drawing. Example:

isopropyl alcohol --- A volatile, flammable liquid used as a solvent; commonly known as rubbing alcohol.

isotropic --- Having the same properties and characteristics in all directions. The opposite of this is anisotropic. Wood is anisotropic.

IWCS --- International Wood Collector's Society. An organization that is focused more on the botanical nature of wood than on its uses. They have local branches in many places and put out a very informative magazine, contributed to by many of their extremely knowledgeable members. They are easily found online. They sell a reasonably priced kit of standard sized wood samples a with very nice variety but with a quality so shoddy that it is unthinkable that a commercial organization would produce it.

jackhammer --- A very heavy one-man machine that uses compressed air to power the up and down motion of a strong steel bit, used to break up concrete, stone, pavement, etc. This is that amazingly noisy machine that you see in use when streets are being torn up. Also called a pneumatic drill. This is not even remotely a woodworking tool, but is included in this glossary because of the word hammer in the name. Examples:

jack stud --- Another name that is some times used for both cripple studs and trimmer studs. A king stud is never called a jack stud. That would be insulting.

Jacob's chuck --- A particular type of drill bit chuck which can also be held in the headstock or tailstock of a lathe. This is a little like "kleenex" --- it's a word that started out as a proprietary name but is now used as pretty much synonymous with "drill bit chuck". It can also be used to hold a small workpiece, instead of a drill bit, so that the workpiece will rotate in the lathe or drill press. Examples:

jalousie window --- synonymous with louvered window

jamb --- The vertical side members of a door or window frame, including the frame itself and the studs that support it, and any trim mounted on it. On a door, the two sides are called the hinge jamb and the strike jamb. See also head jamb.

jamb extender --- An extension of a window or door frame to make it flush with a finishing surface such as the internal wall.

jam chuck --- sometimes synonymous with spigot chuck, sometimes synonymous with cup chuck.

jam nut --- a thinner than usual machine nut that is used specifically to be jammed up against a normal nut (or possibly another jam nut) so that the pressure of the two on each other makes it very difficult for either to move. The point is to create a situation where the pair of nuts together will not loosen due to vibration whereas a single nut might. Jam nuts are typically half the thickness of normal nuts. They can also be used in situations where it is desirable to tighten a nut quite a lot but without putting pressure onto the object that the bolt is going through; in this situation the normal nut is put into position with light pressure and then the jam nut is tightened up against it so that the two together will not vibrate off of the bolt, but there is only light pressure (by the nut on one side and the bolt head on the other side) against the pieces being clamped together. Examples:

Janka --- A unit of measurement used to describe the surface hardness of wood. A Janka rating is determined by the amount of force required to drive a 0.444 inch steel ball half its diameter into the wood product. The force is expressed as either kilonewtons or pounds. Below are a few woods and their Janka hardness in pounds, showing the general range of the hardness of woods. For a full list of Janka values, see JANKA TABLE and for further discussion, see JANKA DISCUSSION.

80balsa wood
300 => 400soft cedars and pines, paulownia,
some poplars and cottonwoods
easily dented with a fingernail
1100 => 1300various oaks
~2000mesquite, purpleheart, hickory
~3000various ebonies
4500lignum vitae - you can drive nails
with this stuff !
~5000Australian bull oak

Japanese joints --- This refers to joints that are very intricate and require great skill and patience. Although, as I understand it, these joints are a normal part of joinery in Japan, they are not much used in the USA. An example of such a joint is the triple miter joint.

jaw --- The opposed gripping portions of tools such as pliers and vises, so named because of the resemblance, in function at least, to human jaws.

J bolt --- A rod threaded on one end and then bent into a "J" shape. Most often the bend is a uniform "U" shape but it can be more circular or less circular and more of just a slightly-more-that-90-degrees bend. The purpose of a J bolt is to be embedded in concrete with the threaded part extending up out of the concrete and thus, like it's cousin the L bolt it is sometimes called a "cast in place" bolt. Examples:

jig --- A device used to hold work or act as a guide in production or assembly. Jigs may be shop-built or manufactured for production. One-off jigs are commonly made by woodworkers to assist in the production of various items where there might otherwise be great difficulty in, for example, making special cuts or obtaining an odd angle for drilling. A common type of manufactured jig is one that assists in creating mortise and tenon joints for drawer sides. It is not uncommon to spend, for example, 20 minutes making a jig that gets 10 seconds of use, because without the jig, you just can't do what it is you need to do. That is, jigs are sometimes not timesavers so much as enablers. When used over and over, the "enabler" types frequently ARE timesavers.

jig saw --- (1) [also jigsaw] Used as synonymous with what is more commonly called a scroll saw.
jig saw --- (2) [also jigsaw] A hand-held portable saw with a small plate that sets on the work being cut and through which there projects a short (6 inches or less) blade that moves up and down very rapidly. Such saws are very versatile, with many different blade types and sizes for cutting various materials. Although they can make fairly small radius cuts, they are not really comparable in that regard to a scroll saw because the scroll saw, which holds the blade on both ends, can have much narrower blades. When homemade from wood, what is called a "jig saw puzzle" is actually made with a scroll saw, not a jig saw, because scroll saws used to be more commonly called jig saws. A jigsaw is usually held with the blade vertical, and pressure has to be applied to keep the plate in firm contact with the workpiece or else the saw, the hand holding it, and the workpiece will all go into a very unpleasant vibration, that will really wind your watch (for those of us old enough to remember non-digital watches). A larger, more powerful version, used mainly for cutting tree limbs, is called the reciprocating saw. Like the reciprocating saw, the jig saw is also sometimes called a "saber saw". Examples:

joiner --- A woodworker who specializes in the construction of building components such as windows, doors and stairs, where the creation of good-fitting joints is very important. The objects created by a joiner are called finish carpentry.

joinery --- At the fundamental level, joinery just means creating joints between pieces of wood, but the term carries with it a connotation of fine woodworking and the creation of subtle joints that make good use of craftsmanship and woodworking skill, not just saws and nails. Nailing a couple of two-by-fours together is not joinery, creating elegant and virtually seamless dovetail joints is. In a secondary sense, it means the creation of joints in wood without the use of nails (or other metal fasteners), joints which hold together by a combination of adhesive and interlocking pieces in the edges of the pieces of wood. In a broader sense, the term is used as synonymous with cabinetry, which goes beyond just making joints. There are fundamentally two types of joinery, frame joinery and carcass joinery.

joinery chisel --- A chisel that is used to create and/or clean out a groove of some sort that is part of a joint. These, particularly the mortise chisel, tend to be stronger and stiffer than carving chisels. They often are cranked chisels. Examples

need to add joinery chisel pics

joint --- (1) The edge where two touching members or components come together
joint --- (2) The space between two touching members. One of the goals of joinery is to have clean, tight joints that are invisible, or as nearly so as possible.
joint --- (3) A type of cigarette. After smoking such a cigarette, one should avoid power tools and adhesives.

types of joints and joint-related terms:

jointed --- (1) As regards woodworking, this means joined together using any of the many joints used in joinery.
jointed --- (2) As regards tools, this means having hinged joints (like your elbow) that give certain tools or tool parts the flexibility they need to move with versatility.

jointed core --- This refers to lumber core plywood that has had the edges of the core pieces machined square. APA standards call for the average distance between lumber sections in such a core to be no more than 3/16th inches and for no one gap to exceed 3/8".

jointed flooring --- Strip flooring manufactured with square edges, no tongue or groove, and usually end-matched. Used principally for factory floors where the square edges make replacement of strips much easier than with tongue and groove flooring. Also called "square edge" flooring.

jointer --- A power machine used to true the edges of boards, usually in preparation for gluing. They have rotating blades (usually a set of three blades), mounted horizontally in a holding mechanism and an adjustable infeed table that allows adjustment for the depth of the cut so that multiple passes can be made on boards that need to have a lot of material removed but not all at once. If the blades are set a little too high, then when the end of the plank leaves the infeed table, snipe occurs. Most models come with an adjustable fence, which allow one to edge boards at an angle other than 90 degrees which can be invaluable if you are making, for example, a box that is 5-sided or 6-sided instead of 4-sided. Such models are called "parallelogram" jointers because when the fence is leaned over from 90 degrees, the place where the bed and fence meet looks like one side of a parallelogram. Jointers can also be used as surface planers for narrow planks. Examples:

jointing --- The process of putting pieces of wood together by means of joints

joint staggering --- The process of laying flooring planks such that the places where the ends meet do not fall next to each other but rather are staggered across the width of the floor. This results in both a better looking floor and also more mechanical stability.

joist --- One of a series of regularly spaced parallel horizontal beams used to support floor or ceiling loads and supported in turn (usually at the ends) by larger beams, girders, or bearing walls. The angled beams that support a sloping roof are not joists but rafters but if the roof is flat, then the roof supports are joists. A joist may be as small as a 2x4 or much larger, and it could be, as examples, a pine 2x4 or large I-beam made with composite materials, but in any case it will have its wider face oriented vertically. Examples:

joist hanger --- synonymous with beam hanger

juvenile wood --- Wood formed early in the life of a tree, and which is therefore at the center of the tree. In terms of lumber, juvenile wood is lower in quality than wood which forms later and this is particularly true of the softwoods. Juvenile wood is of little or no concern in paper and fiber products and in products in which wood is reduced to individual fibers, fiber bundles, or small pieces prior to product manufacture. In juvenile wood, the length and thickness of cell walls can be significantly different than that of mature wood in the same tree and it is less stable (more prone to "movement in service than mature wood. The two most troublesome characteristics of juvenile wood are that (1) It shrinks and swells along the grain as moisture content changes and (2) the strength is lower, and in some cases much lower, than mature wood of the same tree. Some smaller trees in particular, e.g. staghorn sumac, have a juvenile wood center that is totally punky and if it is included in the small planks produced from the tree, it can be scraped out with a fingernail. Also called young wood or core wood or pith and to be contrasted with mature wood.

karelian --- synonymous with masur

KD --- Kiln Dried

Kep nut --- see lock nut

kerf --- (1) The area of cut made by a saw blade. That is, the area where there used to be wood before the saw blade cut it away.
kerf --- (2) The width of a saw blade --- determines the amount of wood that will be removed by the blade. Standard-kerf circular-saw blades have a 1/8" kerf. Narrow-kerf circular-saw blades have the dual advantages of removing less wood and requiring less force.

kerfed --- cut as described with the term kerfing

kerfing --- Making a series of parallel crosscuts part way through one face a length of wood so that the piece can be curved towards the kerfed face, or similarly in a stick so that it can be curved.

ketone --- An organic compound that is a strong, fast-evaporating solvent, used as part of paints to stabilize the other ingredients so that they don't degrade as quickly over time. Also used as a solvent; acetone is a ketone.

key --- A support element used in joinery. The most common type of key is a flat arrow-head-shaped piece of wood as shown with the keyed edge miter joint and the keyed face miter joint but there is also the dovetail-shaped key element as shown with the the butterfly joint and the butterfly keyed mitered frame joint. The term is also used with joints where the "key" is not a separate element, but rather a way of making a joint more resistant to separation; this is best exemplified by the keyed lap joints such as the keyed dovetail full lap and keyed dovetail half lap

keyed dovetail full lap --- A full lap joint where the cross piece is cut with a dovetail groove instead of a rectangular groove, and the inserting piece is a large dovetail the full width of the plank. This increases the strength of the joint over just a rectangular groove. As shown in the examples below, the joint can be through or half blind. Compare/contrast to dovetailed full lap. Examples:

keyed dovetail half lap --- A half lap joint where the cross piece is cut with a dovetail groove instead of a rectangular groove, and the inserting piece is a large dovetail the full width of the plank. This increases the strength of the joint over just a rectangular groove. As shown in the examples below, the joint can be through or half blind. Compare/contrast to dovetailed half lap. Examples:

keyed edge miter joint --- An edge miter joint which is strengthened with a key. Unlike in the drawing below, one does not normally actually make the "arrow" insert so precise but oversize and then it is worked to fit after gluing. Also note that the arrow shaped key in this joint is also called a feather spline. Example:

keyed face miter joint --- A face miter joint which is strengthened with a key. Not to be confused with the very similar joint, the face keyed miter joint which has keys on the faces instead of inside. Unlike in the drawing below, one does not normally actually make the "arrow" insert so precise but oversize and then it is worked to fit after gluing. Also note that the arrow shaped key in this joint is also called a feather spline. Example:

keyed miter joint --- This refers to any edge miter joint or face miter joint in which one or more small arrow shaped splines (feather splines) are inserted into both planks to a depth that is less than what would make them protrude through to the inner side. The two examples in this glossary are at keyed face miter joint and keyed edge miter joint

keyhole saw --- A small hand saw with a long narrow blade that tapers to a point. It is used primarily for cutting small-radius holes in drywall and the point allows it to be jabbed into the drywall at the start of the cut. The handles come in a wide variety with the two basic types being a handle like that of a knife and the other being a more traditional saw handle. Examples:

keyless chuck --- A drill chuck (see chuck) that does not require a chuck key but instead can be tightened and loosened by just twisting the end. Very common on battery operated power drills Examples:

kickback --- (1) The action of a workpiece being thrown back towards the operator by a moving blade or cutter or the action of a power tool when it jumps backward as a result of its blade or cutter jamming against the workpiece. One of the main reasons for kickback is case hardening of wood. Kickback can be dangerous and can sometimes be prevented by anti-kickback devices such as featherboards and pawls which are used on stationary saws.
kickback --- (2) A logging term describing the bottom of a cut tree jumping back over the stump toward the feller. This generally results from the lack of a proper stump shot and/or a tree being felled into standing timber which prevents proper tree-fall.

kicker --- A strip of wood fixed above a drawer’s side to prevent the back of the drawer from tipping upward as the drawer is withdrawn.

kiln --- As regards wood, this refers to a building, usually quite a large single-story building (often like a giant shed), that is used to dry out wood (in a process called kiln drying) more quickly than it would dry out on its own if just sawed into planks and then left out in the air (air drying). The building is fitted with fans, heaters and dehumidifiers so as to control the temperature and relative humidity of the air and its flow around the drying lumber. In pottery, a kiln is a smaller building, often too small to merit the term building, where ceramics are brought to very high temperatures ("fired") to solidify them a fix the finish. Commercial brick fabrication operations utilize very large kilns, generally of a type that allow bricks to pass through on some sort of conveyer system so that it is a continuous process.

kiln brown stain --- synonymous with brown stain

kiln dried --- wood that has been artificially dried in a kiln to bring the moisture content of the wood down to an amount (typically 6% or a little more) that will ensure that the wood will not suffer movement in service. Sometimes wood is air dried for a while before being kiln dried. Drying lumber in a kiln is a commercial necessity because some timbers can take years to dry on their own in the air, even when cut into planks and stacked with stickers. Kiln drying does sometimes induce problems, called drying defects, so the process becomes something of a trade off between rapid drying (the reason for using the kiln in the first place) and the quality of the resulting wood. Very precise drying schedules have been developed for all commercial timbers, based on empirical results. Roughly speaking, this process reduces moisture content in just days or weeks to about 6 to 10 percent for hardwoods and high-grade softwoods, 12 to 20 percent for construction lumber.

kiln drying --- see kiln dried

kiln schedule --- synonymous with drying schedule

kiln wet --- Describes lumber that has gone through the kiln drying process, but still contains more moisture than is allowable for kiln-dried lumber.

kindling --- Thin, dry wood used to start a fire.

kingdom --- see taxonomy for a discussion

king stud --- A stud that runs all the way from the bottom plate to the top plate. Compare/contrast to cripple stud and trimmer stud. Examples:

kink --- a localized fairly sharp crook, as opposed to the normal more gradually curved crook, most often due to a knot and only likely to happen in fairly narrow stock.

kino gum --- A gum obtained from various tropical plants; used as an astringent and in tanning.

K-lock nut --- see lock nut

knee brace --- A diagonal corner brace fastened between a vertical element (such as a structural column or a table leg) and a horizontal element (such as a beam or truss or a table rail) to provide lateral support and restraint. A very short knee brace is called a corbel. Examples:

knee wall --- Any wall that is quite short (typically comes up to about knee height). Often found as the outer wall in a 1 1/2 story house, where the knee wall supports the roof rafters. Aka "half wall" and "partial wall".

knife burn --- synonymous with machine burn

knife checks --- Splits along veneer caused by poorly adjusted veneer slicing knives at the manufacturing plant.

knife marks --- Obviously, in standard English, this could refer to marks made by any knife, but in woodworking, the term normally refers to marks left by planer knives during the dressing of a plank. Such marks can be so light that they can hardly be seen or light enough that they can be readily seen but still don't cause any uneven feel in the surface, or they can be so bad that the cause a washboard effect in the surface. In any even, if they are at all visible, they are unacceptable in a final product (that is, an item such as a cabinet, made from the plank) so will have to be taken off with a power sander of some sort.

knockdown --- (1)[adj] A design feature that allows a piece of furniture to be easily disassembled by the use of special hardware or joinery (sometimes called knockdown fittings and/or knockdown joints.
knockdown --- (2)[noun/verb] The process of disassembling furniture that is built as described in the adjective definition above.
knockdown --- (3)[noun] see knockdown joint

knockdown fittings --- Mechanical devices (hinges, etc.) for joining components in furniture that has to be easily dismantled. See also knockdown joint.

knockdown joint --- Any joint that is constructed without glue and in a way that it can be disassembled easily. Such joints often use removable wedges but may also use various metal fasteners that allow for disassembly.

knot - An area in wood that once formed the base of a branch growing from the trunk of living tree but which has been subsumed by the tree, sometimes as live wood (a red knot), sometimes as dead wood (a black knot). The knot is a cross section of the wood fiber that at one point was the branch. Because branches grow at more or less right angles to the trunk of a tree, knots have fiber direction that is at right angles to the trunk fibers around it and this causes local grain irregularities and crotch-like areas.

During the development of a tree, the lower branches sometimes die young and sometimes last for years and then die, and sometimes don't die at all. Subsequent layers of growth of the trunk go out around these cylinders of fiber. If the branch has died, the branch fibers are no longer intergrown with the trunk, producing "encased" knots that are likely to drop out after the tree has been sawn into boards. If the branch is alive, the branch fibers are "intergrown" with the trunk fibers and these cylinders of branch fibers produce "intergrown" knots which are integral with the surrounding wood.

Knots are defects which weaken timber and lower its value for structural purposes where strength is an important consideration. The weakening effect is much more serious, when timber is subjected to forces perpendicular to the grain and/or tension, than where it is under load along the grain and/or compression. The extent to which knots affect the strength of a beam depends upon their position, size, number, direction of fiber, and condition. A knot on the upper side is compressed, while one on the lower side is subjected to tension.

The shape of a knot will depend on the angle at which the branch grew from the tree and the angle of cut of the section of wood in which it exists. For an estimate of knot sizes and names, see knot sizes. There are four basic considerations for knots. In woodworking terms, the frequency of knots only occurs, as far as I know, in the term "knotty" which is a description of wood figure, and the size of knots is given in this glossary in the entry on knot sizes. The terms for shape, quality/condition, and relationship with surrounding wood are listed below with brief definitions and each is a link to a more complete definition. There are numerous other terms, used with some aspects of knots, that I have found in various references but that I do not see as being particularly helpful or useful. In the spirit of completeness, I have included them here, but with little or none of the extensive rewording and expansion that I normally apply to terms in this glossary. Those terms are down below the knot pics.

types of knots:

Knot types shown are spike, intergrown, encased


knothole --- Void produced when an encased knot drops out of lumber.

knot sealer --- A shellac-based sealer used to coat resinous knots that would otherwise stain subsequent finishes. See resin bleedthrough.

knot sizes --- I'm not sure there is really any consensus on knot sizes, but the figure below is from one reference that believes it has a standard. "Pin knot" sizes are generally stated as being 1/4" and below, as shown on this chart, BUT I have seen a couple of references that say "pin knots" are anything less than 1/2". For what it's worth:

knotty --- Wood that has a significant number of knots. Particularly used with pine to distinguish knotty pine from clear pine (which has no knots). Example:

knuckle --- see hinge knuckle

knuckle length --- see hinge dimensions

knurled --- Refers to a surface that is cross hatched,or otherwise roughed up to provide gripping. Commonly done on small knobs.

knurling --- The creation of a knurled surface.

Kraft paper --- Heavy brown paper sometimes treated to be water repellant and sometimes used as flashing around window joints.

for images of wood itself, go here: wood id site

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