b'\x1b\x1a\x19 \x1f\x18\x1d\x17\x16Shop Operationsset center drills to spot only. Letsalready has a lot of time investedverify the setup when drilling is to face it: Were only human, andin it, care must be taken that holesset the center drill to just lightly spot sometimes we screw up. Whenand other part features end up inthe surface. If the locations happen drilling a part, especially one thattheir correct locations. One way toto be off for some reason, youll have a chance to correct the error.Manually set countersink depths at the machine. Coun-tersinking tools run the gamut in terms of how they are made. They vary in numerous ways, such as angle, tool tip size and number of flutes. These variations make it difficult for a programmer sit-SYSTEMS ting at a computer to set a pre-cise depth. Because machinists generally set a precise depth for a countersink tool, a programmer likely wont know which counter-sink tool will be used. Instead, I program the tool tip to stay a little above the part and let the ma-chinist manually find the correct Z negative value, which then can be entered into the canned cycle that runs the tool.The easiest way Ive found to do this is to run the program until the countersink tool is called up. Then, stop the program by hit-ting the reset button. After that, start the spindle with the clock-wise, or CW, button, and slowly Boring handle-jog the tool to the proper depth in the part. Take note of the Groovingabout the authorThreading James A. Harveyis a machinist Broaching and moldmaker. This column is Special tools adapted from his book CNC Trade Secrets: www.GUHRING.com A Guide to CNC Machine (800) 776-6170 Shop Practices from Industrial Press Inc., South Norwalk, Connecticut.24JULY 2019 ShopOps.indd 24 6/14/19 3:36 PM'