Quote:
Originally Posted by DampRobot
I've always known we had boring tools for the mill, but have only ever used a boring bar in the lathe. Is the procedure to set the boring bar to the appropriate radius above the part, and then cut, or to somehow adjust it while in the part? I ask because on the lathe, I often adjust the radius of the cut while inside the part (so long as the part isn't too thick).
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I don't know what a machinist would tell you, or an instructor if you took a class, but the way I've always done it is to visually adjust the boring head above the part so that you'll take a small cut. Make that cut and then measure the diameter of the hole. Once you know the diameter of the hole you know how much you need to adjust the boring head. Odds are that unless you need to remove a very small amount, you can't go immediately to this number, but you at least know your starting point. In a production environment I'm guessing you would have some kind of offline fixture that would allow you to adjust the boring head to the right dimension with no trial and error.
If I'm understanding your question correctly you're asking if you can change the cutting diameter of the boring head without retracting it from the hole?
To adjust the cut diameter you have to turn a screw that is mounted radially on the body. The machine has to be stopped to do this, but if you're inside the hole and you try to increase the cut diameter you will push the boring head against the wall of the hole (see below).
You could do it in the hole if you moved one axis of the machine away from the hole, but you will still have to retract the tool from the hole and come back to the zero position to re-start your cut . This is common on CNC mills, so that they can retract the boring bar from the bore without scraping the wall.