Hello,
Some times ago, ago Arch, gave us this Tip :
********************* " I found some self drilling sleeve anchors for concrete, hardened and about 7/16 in, diam. X 1 1/2 in. long. The toothed end closely resembles a small version of a Stebcenter. There is no center pin, but the thru hole at the toothed end is 1/4 in. and half way thru the other end is
5/16. both ends with standard female threads.
Looks easy to make a small drive center to be held in a Jacobs chuck by adding a center pin and bolt with the head cut off. Or add a spring and center pin to make a 'Stebcenter'. "
********************** Last year, I actualy made one from a "Spit M8" used in caving speleology (before the age of "battery powered drills" !).
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As you can see on the photo, I just add a hard steel nail, fixed a washer on it, add a spring (from a pen) to power both, and drill some rod and brass M8 screw ... et voila ... you can use it on a Jacob chuck ...Have nice shavings from France :-)
JYS