Oak grain splits easily if cut lengthwise, but when crosscutting hardwood grain, it's difficult to avoid tearout. The saw pulls on fibers until they bend and snap. In rough cuts, you can see pits where fibers were plucked. Instead of sawing a clean slice, fibers are bent and torn off if wood grain is unsupported. Variations in wood grain coming from diverse climates of the globe can present a challenge to those trying to coax forth a fine crosscut.
The entry angle into a board affects the finish quality. The relaxed faces shown here scrape with some resistance for better control of tearout. A high top bevel with an acute needle point slices neatly across splintery wood grain and can reduce chipping in double face laminate. Sides that are nearly flat can burnish a glassy smooth finish.
Feed rate slows to a leisurely pace for a smooth crosscut. Fine blades inhibit the rate of movement by nibbling slowly in tiny bites close together, instead of chomping big bites. A fine tooth saw gives you more time and control. A hardwood board is fed slower than a softwood like pine. To cut plywood or veneer without splintering, you'll need at least a minimum of 60T on ten in. Super fine spacing of 100T would slow a finishing cut to a careful crawl. Get it spinning full blast and then start sawing. It won't make a smooth cut if it is bogging down.
Let tips enter on the finished side to avoid chipping. If they go in the back and exit the front, the brittle surface will chip or crumble outward. Chip-out is less likely when you are cutting through the good side into a supportive backing. Laminated flooring planks and plywood are cut finished side face up on a miter, radial arm or table saw. For a circular saw everything is facing the other way and the good side of the panel is face down.
The brittleness of double face laminate makes it tend to chip easily. To reduce chipped laminate on top, raising a table saw blade adjusts its entry. Techniques for avoiding chipping on top may simultaneously cause tearout on the face down surface. Scoring the bottom of the melamine first helps. A very shallow scoring pass is made with the position lowered. The next time lift it to go all the way through the face up melamine. A primary saw is sometimes paired with a second, small scorer. Alternatively, use a knife to score it by hand. Luan or balsa can also be die-cut.
A typical cause of tearout is lack of support beneath a panel or countertop drooping and shaking as it is cut apart. Preventing vibration can effectively quell splintering.
For avoiding tearout on the bottom surface, a zero clearance insert in a table saw gives close, rigid support to stop the splinters bending. The metal throat plate capping the oval hole can be taken out and a wooden one fitted in its place. The blade is lifted to slice a narrow slit to provide a stiff guide line where the grain fibers can snap crisply. It gradually wears out, so keep an extra homemade insert ready for finishing work.
For accurate crosscutting, use a sled to improve stability. A crosscut sled is a deck you slide on plastic runners in miter slots. A homemade sled is usually two feet square. A zero clearance opening is slit front to rear. Fences are fixed fore and aft at 90° or 45° for an accurate miter gauge.
Runout and tearout
Runout is deviation from a true circular path resulting in vibration. It should run quiet and make smooth cuts if ground to fairly close tolerance within .002 inch. Stay alert to runout issues by listening for rhythmic buzzing. Watch to see whether the rim appears to hop up and down. If so, it's grossly out of joint or non-concentric. When the high side is doing the most work, it is ineffective at making a clean cut.
Table saw alignment
Tearout and splintering can be due to poor alignment. Unplug it and elevate the blade. Measure the distance over to the miter slot from both the front and the heel. To be parallel, the measurements must match. If not, loosen the bolts underneath the top so you can adjust its position.
Bearing play is relatively rare, but can seriously wreak havoc with accuracy. Take off the belt, then spin the shaft and note any hesitation. Tug it to feel for looseness, which causes wandering.
An unstable blade tends to begin deflecting as pressure increases. Flexing causes splinters and wandering. A ragged splinter may be tolerable in a hidden place, but sloppy swerving and wandering aren't acceptable. If the desired goal is fine finish cutting, you won't want to tolerate any deflection. You might expect less chipping by thin kerf ones, but they flex and tear out more. A stabilizer collar can calm down flexing. By strictly limiting deflection, you may even help prevent a more lasting problem.
If it seems to deflect even though you're moving cautiously with gentle handling, then turn it off and watch the rim for wobbling as it slows. To stifle wobble, try remounting it, making sure to brush off any debris. If it still wobbles and has dark spots on its sides, it may have developed warp. If that's true, tweaking or adjusting its position would not improve the problem significantly. Adding a stiffener after you've noticed warping probably won't fix it.