...for drilling a hole through a cylindrical piece (such as a timing rod) and having the finished hole centered.
Place the part to be drilled in your drill press vise. Put a stiff pilot (center) drill in the chuck and balance a small ruler on top of the part to be drilled. Lower the drill point down until it touches the ruler. Did the ruler dip to one side? Probably, so move your vise/part until the ruler is parallel by eye with the drill press table. Remove the ruler and carefully drill a small dimple with the pilot drill. Swap out the drill for the desired finished size and drill through. Voila! A perfectly centered hole.
This works because the ruler (or other piece of straight, light stock) magnifies any error so that it can be see by the naked eye and corrected. I actually used this technique to drill the wrist pin hole in a home made piston once and it worked beautifully.
Now I have a nice hole thru my ruler, Just kidding
Yes this is a cool way to center a cutter in the lathe as well
I usually use one of these
there is a grove in the bottom that you use to line up the drill before putting your work in there
I too, have a number of "high end" centering gizmos but most of them stay in the tool chest nowadays .
And Gene you're correct....I use the same technique for setting up my lathe bits.
I use a angle iron but your's is nice!!! Bud in Wheller,Mi.
The same method works well for lining up a tool bit w/the centerline of a lathe spindle and tailstock.
OR just invest in V blocks...
I think I need to add something here....
The V blocks and angles are all work HOLDING fixtures.....they do not center the cylindrical piece under the spindle axis of the machine. You can get close by eye perhaps, but the ruler stunt will get it on dead center each time.