Wood Characteristics

The species of wood, as well as condition, will affect planing ability—the harder the wood, the more difficult it will be to plane. We have included a list of wood characteristics you may encoun- ter when planing, The following descriptions of defects will give you some possible answers to problems that may arise.

Chipped Grain (Tear Out) — Usually a result of cutting against the grain, or planing wood with knots or excessive amount of cross grain. Chipped grain can also be caused by dull knives or misaligned chip breaker. Often, chipped grain can be avoided by slowing down the feed rate and by taking shallow cuts, If those options do not work, inspect your lumber and determine if its grain pattern is causing the problem. If the wood does not show substantial crossgrain, inspect your knives for sharpness and inspect the chip breaker for proper alignment.

Fuzzy Grain (Raised Grain) — Usually caused by surfacing lumber with too high of a moisture content. Sometimes fuzzy grain is a characteristic of wood such as basswood. Fuzzy grain can also be caused by dull knives or an incorrect grinding bevel. Check with a moisture meter. If moisture is greater than 20%, sticker the wood and allow it to dry. Otherwise, inspect the knife condition.

Glossy Surface — Usually caused by dull knives taking shallow cuts at a slow feed speed. Surface gloss will usually be accompanied by overheat- ing. Lumber will often be scorched and eventually damage to the knives will occur. If the knives are sharp on inspection, increase feed speed or cut- ting depth.

Snipe — Occurs when board ends have more material removed them the rest of the board. Usually caused when one or both of the table roll- ers are set too high. Can also be caused by the chip breaker or pressure bar being set too high. However, a small amount of snipe is inevitable.

Snipe can be minimized by proper adjustment of the planer components, but complete removal of

snipe is unlikely. More likely, you will be able to reduce it to a tolerance of .002". If snipe under that level is a problem, consider cutting lumber longer that your intended work length and cut off the excess after planing is completed.

Uneven Knife Marks — Uneven knife marks can occur when the chip breaker is set too high. Inspect cutterhead bearings if re-adjustment of the chip breaker fails to remedy the situation.

Chatter Marks — Usually caused by incorrect chip breaker and pressure bar setting heights. Chatter marks can also be caused by running a narrow wood piece through the planer at either the right or left end of the cutterhead. Chatter, like uneven knife marks, will show in the form of a “washboard” look. Chatter marks are more likely to be inconsistent in appearance than uneven knife marks.

Wavy Surface — Caused by poor knife height adjustment, wavy surface appears when one knife is taking deeper cuts than the rest of the knives. Remedy by resetting the knives to a toler- ance of approximately .001" from one end to the other.

Pitch & Glue Build-Up— Glue and resin build- up on the rollers and the cutterhead will cause overheating by decreasing cutting sharpness while increasing drag in the feed mechanism. The result can include scorched lumber as well as uneven knife marks and chatter.

Chip Marks — Occur when chips are not prop- erly expelled from the cutterhead. The knives catch the chips and drag them across the lum- ber being planed. Chips tend to be random and non-uniform (compared to chipped grain). This problem can be caused by exhaust blockage or too much room between the cutterhead and the chip deflector. Using a dust collection system in combination with the planer can help reduce chip marks. Inspect the chip deflector and re-adjust spring tension.

-18-	Extreme Duty Planers