# Centering trick



## Cedge (Aug 24, 2007)

This trick is another down and dirty time saver. It came from one of the old machinist books I've noticed collecting aound the house of late.

When working with round stock on a mill, its sometimes difficult to make sure you are dead on center with your cutting tool.  Here's a double for one money. 

Once you have the stock secured on the table, grab a piece of drill rod ( use 1/4") and put it in your chuck. Now pull your handy dandy little metal ruler from your pocket and place it against the work piece. Gently move the drill rod up against the rule and observe the angle of the ruler.  Move the mill table right or left until the rule is square to the table.  You'll be surprised at how fast you come within a thousandth or so of dead center.   From there, install your wiggler or edge finder and finish centering.

This trick is also an excellent way to adjust the cutting tool height on your lathe.  Place the ruler between your cutting tool and the work piece. Run the cutting tool up against the ruler and observe the angle of the ruler.  I use a small square or 123 block aligned against the bed bevel to check the ruler for square. Adjust the tool up or down as required to square the ruler. I generally run my tool just barely below the centerline, so the ruler will be tipped just the least bit forward from square.

 The trick equally works well with adjustable Quick change, Rocker and Latern style tool posts.  Give the work piece a quick facing cut to check the cernter of the cut for any coning or remaining metal and you're ready to run. 

Steve


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## jgarrett (Aug 25, 2007)

Steve, Great tip... I have found that a double edge razor blade (if you can find one) is even more accurate.
Julian


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## Cedge (Aug 26, 2007)

Julian
I've used the razor blade method when aligning the tail stock and it works a trick since it gives a good visual cue on multiple planes.  The ruler works well when only one plane is being checked and I usually have the ruler on the table or in my shirt pocket.  Not highly recommended with a double edge razor....(LOL)

Steve


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