Fingerpulls for Cutting Board

Instructions

Step one: Mill pocket 16mm deep. If you have BenchPilot, the pocket will extend to the cut line. If you don't have BenchPilot, you need to make an inside cut to the cut line before or after pocketing. I used Shaper's 16 mm clearing bit for this step. Your mileage may vary, but I used a spindle speed 3.5 and a feed rate 15 ipm. That's sort of slow, but at faster feed rates the bit struggled in the corners and the cuts were uneven. 15 ipm cut cleanly and didn't burn using the 16mm bit. This was on softwood. UPDATE: Based on my experience with a couple walnut cutting boards, I recommend 3 passes with a spindle speed of 2 and 15 ipm. Step two: (a) Switch to the fingerpull bit. Use 22 mm bit diameter. Be sure to Z touch! (b) Change from pocket cut to inside cut. Cut depth remains 16 mm. (c) Add a negative offset. You ultimately will need a negative offset of 5 mm (minus 5mm to say it another way). I made three cuts: First with 2.5 mm negative offset, second with 4.5 mm negative offset and finally the full 5 mm negative offset. That worked fine for this wood. I'd probably use more passes in hardwood. UPDATE: Based on a couple walnut boards, I recommend spindle speed 2, negative 1.5 at 13 ipm, then negative 3 at 13 ipm, then negative 4.2 at 13 ipm, then negative 4.8 at 20 ipm, then the full 5 negative at 25 ipm. (d) If using BP or Autopass, make sure to cut to full depth on a single pass. No roughing pass. (The successive increases to offset are sort of a substitute for roughing.) (e) Note that about half of the cut line is air. This is to allow the fingerpull bit to plunge in the air. If the bit plunges on the wood the plunge will wreck the wood. To plunge in the air if you are using Bench Pilot, at the "Preview Cuts" stage, make sure the bit is positioned outside the cut line (over the air, not the wood) when you start the cut. You also want to make sure BP is done ramping before the bit gets to the wood. So don't use too slow a plunge speed. And of course only retract when the bit is in clear air (BP does this for you if you start in clear air). (f) For hardwood, spindle speed of 2 worked for me. See item (c) for feedback rate. (g) Make the inside cuts using multiple offsets described in item (c). NOTE: I started with clean bits, and cleaned them after each operation (for instance, clean the 16 mm bit while the fingerpull bit is cutting). I think keeping the bits clean reduces burning. I buy walnut and maple cutting board blanks from CiC Workshop: https://cicworkshop.com/products/inlay-builder-kit To get just the cutting board, specify “none” for the inlay top. Nice silicone cutting board feet can be purchased here: https://cuttingboardfeet.com/