Dad’s drill index

Shoot. I wish I'd recalled some time ago that I had this. My 1/8" bit had gone missing for a spell and there's one in the back row of this box. But now I know I have this … and my education continues. I need to consult one of my build-a-house-from-the-pad-up brothers-in-law to interpret the index on the lower panel, but now I have a much broader array of bit sizes! Thanks again, Dad!

I forget what prompted this question in my mind, but I wondered about the optimal width, depth and spacing of the groove that pulls out the material being drilled. I suspect that the depth is somewhat determined by the desire to keep the bit itself strong enough to resist breaking and that this helps determine the width and separation of the groove to pull out material. I need to have a mechanical engineer friend, especially since my dads are gone…

1 year ago (“Back at Lambert-St. Louis International…”): http://365project.org/rhoing/365/2015-04-20
2 years ago (“Happy Easter!”): http://365project.org/rhoing/365/2014-04-20
3 years ago (“Looks like a 5-course meal to me!”): http://365project.org/rhoing/365/2013-04-20
4 years ago (“Finally!”): http://365project.org/rhoing/365/2012-04-20
5 years ago (“Losing its top…”): http://365project.org/rhoing/365/2011-04-20

[ IMG_9932S8x12tm :: f/5 (–0.3) :: 1/50" :: ISO-400 :: 45mm ]

[Rick Schies]

Over the years my bits have gone missing too and one of these days I will be forced to replace them