Bits for Machining Solid Wood
CNC pros discuss bits for solid wood machining that will get the job done and last a long time in service. August 14, 2009
Question
What is the best bit to use when machining solid wood? We cut solid wood once or twice every couple of months. Currently, I am using a 3/4" compression bit and making several passes, utilizing the upcut portion of the bit. We fasten the lumber down (usually no more than 8" wide), then make repeated passes at lower and lower depths. Is there a better way to machine small pieces of solid lumber (usually for bullnose edging on countertops with radiuses)?
Forum Responses
(CNC Forum)
From contributor A:
If you are machining it again later with a round over, I would use an Onsrud 60-053 or similar and be done with it. They really reduce chipping, blowout, etc. and produce a smaller amount of side force on the work. It cuts very nice conventional or climb. If you need a nice finished edge, take a cleanup pass in climb with a high speed steel finisher like the 60-200 series slow helix finisher. You can also get the best of both in a chipbreaker finisher style. They work well, but for really nice results use the two bit method and just wheel it into the finish room.
From contributor B:
Why are you only using the upshear part of the bit? Compression bits and even downshears will cut hardwoods just fine without filling the slot with chips any more than an upshear if the feeds and speeds are correct. For thicker stock, I used to run a couple of passes down through, but a whisker outside the final dimension. Then I would make a cleanup pass to the final line at full depth to eliminate any lines.
From contributor C:
A chipbreaker finisher (if you are trying to achieve a finished edge) or a "scalloped edge" rougher spiral are the best solid carbide spirals in solid wood. These bits reduce the cutting pressure and allow for higher feed rates and deeper cuts (less passes), than smooth cut spirals. There are staggered tooth carbide-tipped and stagger-toothed insert bits that are fantastic, although the diameters will be bigger. The absolute best tool I've ever applied, though, is called a Novitech. It has interchangeable tips that can be upshear, downshear, or no shear and have a curved face to help curl the chip. These tools, in 3/4" diameter are capable of cutting 2" thick hardwoods in a single pass at aggressive feed rates.
From contributor D:
As another person stated, using a ruffer will provide for a single pass cycle, then use your bullnose on the final pass. A ruffing tool will outlast the finish tool by 3-4 times - a cost savings, and a cycle savings.
