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Shoutout to the guy in Wichita who showed me the 0.002 dial trick on my boring bar | CNC Operators - Free To Speak

Shoutout to the guy in Wichita who showed me the 0.002 dial trick on my boring bar

For 6 years I set my boring bars by eye using the marks on the tool holder and just prayed. Then a machinist named Dale at a job in Wichita showed me to touch off on a scrap slug, zero the dial, and work off the number instead of my gut. First part I ran that way came in 0.0008 under, and I stopped scrapping bores on the finish pass almost overnight. Now my setup takes maybe 10 extra minutes but I have not had a bore come back from QC in 4 months. Anybody else got a touch off trick that saves them on small lot jobs?

2 comments

2 Comments

corap2116d ago

Did you ever try the paper trick for touching off instead of a scrap slug? I read on a machinist forum a while back that you can use a piece of paper between the tool and the part, and when you feel a little drag pulling it out, that's your zero. Paper runs about 0.003 thick so you just touch off, pull the paper, and dial in that number before you start cutting. It's way faster than finding a slug when you're doing one-offs, and you don't have to worry about the scrap piece being out of round or not sitting flat. I started doing this on my boring bar setups and my numbers got way more repeatable, same as what you're seeing with Dale's method. The only catch is you gotta use the same paper every time or your number drifts, so I keep a pack of the same notebook paper in my box.

hannah32016d ago

The "same paper every time" thing got me, because I have absolutely tried this trick and then grabbed whatever was on the bench, which was a fast food napkin one day and a gas receipt the next. My numbers were all over the place and I stood there blaming the lathe like an idiot. Turns out a napkin is more like 0.010 and a receipt is anybody's guess once it gets crumpled. Now I keep one of those little sticky note pads in the box and use the same pad until it runs out, which is way less exciting than hunting for scrap but the parts come out right.