First Drill Sharpened

[RickKrung]

Attached is a close up of my first drill sharpened on my T8. Took it real slow and alternated sides frequently.  Getting the primary facets went pretty quickly.  Getting the secondary facets was taking forever and got to the point of no progress by the time it reached the web.  I finally took off a bunch of the rear on a bench grinder.  Finishing off the secondary facets went pretty quickly after getting rid of all that extra material (5/8" drill).  Thought I was finished and took it out of the jig to take photos, but on magnification, I could see the secondary hadn't reached the center.  So back in the jig to finish it up.  As a result, the second grind on the secondary doesn't span all the way to the tip of the flute, but I believe that shouldn't matter.  In the future, I'll grind the heel away before putting it in the jig. 

Rick

[RichColvin]

Rick,

Your secondary grinds look really good.  Great job!

I had wondered about the value of secondary grinds given that I drill metals with successively increasing sizes on secured work (so there is not a problem with wandering).   But the evacuation of the swarf is so nice that I'll keep doing it.

There is a really good document titled, "Drill Bit Geometry" by Joseph Mazoff that discusses the secondary & tertiary relief grinds at length.  He also discusses a relief grind on the side which I believe he calls a secondary point angle.

There is a link to that doc on my www.SharpeningHandbook.info site.  (This site was written to be a sharpening parallel to the Machinists Handbook.  Not fancy :  just the facts.)

I too am an amateur machinist, and I find I need to sharpen my bits often.  The DBS-22 jig makes that much easier.  And when drilling wood, the tear out is significantly less with sharp bits.

Kind regards,
Rich 

[RickKrung]

Rich,

I didn't even know about secondary facets until I started looking into alternatives to the Drill Doctor sharpening system.  As a matter of standard practice, I drill large diameter holes with successively increasing sized drills, going up a 16th or 8th inch, depending on the type and nature of the drilling (ie., plates on the mill or drill press, versus boring on the lathe, and of course material type).  As often as possible, I locate, often using a lazer centerfinder, and clamp the work in place so it can't move once the drilling starts (this is a given when using a mill as opposed to a drill press).

As part of my searching for drill bit sharpening, I came across Mazoff's article, which is one of the things that turned me toward the Tormek and which is one of the things that eventually, convinced me. 

The other aspect of the Tormek drill bit sharpening system is the device that holds the drill bit.  I have a good friend who has a high speed drill sharping machine.  It sharpens with the conventional wide, flat web and gradually tailing off relief.  Works great and I have sharpened most of my drill index sets with it (#1 - #60, 1/16"-1/2" and A-Z, but have not gone below about #42 on the smaller index set). When I saw that same holder (almost exactly the same), as part of the Tormek drill sharpening jig, I was super intrigued. 

The combination of using a drill holder device that strictly controelils the 180 deg rotation of the drill and the angle control for facet grinding is what sold me on the Tormek.  Also, while the Drill Doctor produced what could be called and industry standard angle and relief, I was just not impressed with the grind finish.  Nothing like new drills, entirely too coarse. 

I have yet to use a drill sharpened on the Tormek (got side-tracked exploring other sharpening aspects), but expect I'll be happy with them. 

Rick