That trick with a piece of tape and a sharpie to mark your tool offsets actually saved my bacon on a rush job.

We had a 50-piece run of these aluminum brackets, and the print called for a 0.005" tolerance on the bore. My usual method of just jogging to the edge and setting the offset was giving me a 0.001" variance that was killing me. I was about to scrap the setup and start over. Then I remembered something an old-timer told me years ago. I put a small piece of blue painter's tape on the machine table next to the part zero, used a sharpie to make a super fine line on it, and used that as a visual reference to consistently touch off the tool in the exact same spot every time. Got the variance down to under half a thousandth and finished the job. Seems stupid simple, but it worked. Anyone have a different trick for nailing down those super tight tool offsets on a manual touch-off?

3 comments

3 Comments

henry18924d ago

My old shop foreman would have called that tape a crutch... he drilled into us that your touch-off pressure should be as consistent as your heartbeat. I got to where I could feel the tenths through the jog wheel. For a five tenth tolerance, I'd just use a half-thou shim stock and pull it with the same drag every time. The tape trick adds another variable if the machine table isn't perfectly clean.

pat_coleman24d ago

Remember how a dirty table could wreck that tape trick?

blairtaylor18d ago

Henry's point about touch-off pressure being like a heartbeat is how I was taught too. I used to think any visual aid was a sign you didn't have the feel. Then I had to hold two tenths on a boring bar in some gummy stainless. The tape trick gave my hands a consistent starting point, and that made my "feel" actually repeatable. Sometimes the crutch is what steadies you.