7 tips to avoid burn marks
Doing everything right but still getting scorch marks from your router bits and tablesaw blades? Try these pointers.
Some of the more common causes of router bit burning are: the use of dull or pitch-gummed bits; a too-fast bit speed (check the speed chart, above); moving the router along your workpiece too slowly; or stopping the router, even for just an instant. If you've already corrected these issues, step up your game with one or more of the following tricks.
Don't start in the corner
When routing edge profiles, apply a layer of masking tape to the edge you plan to rout. The tape makes your first cut (shown above) slightly shallower by adding a layer of material between the bit's bearing and the workpiece. Peel off the tape and rout again -- removing the thin layer of wood
7 tips to avoid burn marks
Starting your cut on a corner forces you to move the router slowly—and that may leave behind burn marks. Instead, move the router at a steady pace as the bit enters the workpiece along an edge; then come back and climb-cut to the corner.
Burn the scrap
Another way to beat burning when starting a cut: Clamp a scrap block the same thickness as your workpiece, as shown. Start your cut in the scrap so that any burning happens there, and rout through your workpiece in one steady motion.
Trying to remove too much material at once forces you to slow the feed rate, which can cause burning. Instead, make repeated, shallow cuts no deeper than 1⁄8 " on each pass. Use the first passes as practice to get an idea of how fast to move your router.
Common causes of tablesaw scorching include: a dull or dirty blade, feeding stock too slowly, or a misaligned fence that causes the workpiece to drag on the back of the blade after the cut. After you've confirmed that those conditions don't exist, consider these pointers.
Set the splitter straight
If your riving knife or splitter is out of alignment, it could be drawing your workpiece against the side of the spinning blade and burning it. Using washers or blade shims, align the edge of the splitter that faces the fence with the edge of the blade's teeth that face the fence.
Measure once, saw twice
Ripcut your workpiece 1⁄8 " too wide. Without the offcut to worry about, you can make a lighter final pass at a faster and more consistent feed rate, removing any burns made on the first pass.
Work with featherboards
Use featherboards to keep your workpiece against the saw table and fence so you don't have to think about holding down the workpiece. Instead, focus on moderating your feed rate and reducing burns.
Eliminate burn-causing hang ups that prohibit a smooth feed rate on your tablesaw by applying a paste wax or commercial lubricant to the tablesaw top. Likewise, a coat of blade lubricant applied to your blades and bits reduces friction and burning.