I just got a Drill Doctor early for Christmas. I've read several articles over the years about the 119 vs 135 degree points. I have sharpened a few bits so far and they seem to do OK.

What have been your experiences?

'64 Galaxie, 390, 4-speed, blower
98 F-250
'52 F-8 dually with planned 460

Ken McWilliams
Dayton, OH
(email address removed to reduce spam)

 

I have sold the Drill Dr. for a few years and used 1 quite a few times. It really is as easy to use as they advertise, and it does a great job. I usually just put the same angle on that was there to begin with.
The sharper the angle the less pressure is feed required, but your cutting edge will increase in length so you will need more power to turn the drill. This really does not come into play in most of the garages across the country, but I just thought I would throw it in there anyway.

 

Use 135 degrees for small drill bits <1/4" above that it does not matter but most are ground to 135. Except some of those asian source drill bits... I swear some of them are 90 degree points!

btw- I am removing the caps from your post title to make it easier to read.

 

A drill point included angle of 118 degrees is considered general purpose, while the "flatter" 135 degree point is for harder materials and is more difficult for the novice to regrind free hand.
By "harder materials" I'm refering to prehardened molding steel like P-20, or oil hardening tool steel like O-1 (Ketos), or air hardening tool steels like S-5, A-2 or D-2.
The 118 deg. point is the standard factory ground angle on all jobber drills unless specified in a special order by the industrial customer. Now there are special purpose drills such as carbide tipped masonry, and some for the aircraft industry that make exception to this rule. The 118 deg. can also be used in wood and plastic, although an even smaller included angle gives better results.
Rate of twist is another issue, but I won't discuss this in this post.
My 35 years as a tool & diemaker/machinist has shown the above to be true and conforms to the info given in the "Machinists Handbook".
I wish to add that the most common mistake made by people using any drill is using excessive speed (SFPM) (RPM) which creates excessive heat that ruins the temper of the cutting edge.
A conservative rule of thumb for mild steel without coolant :
1" drill - 100 RPM & 1/4" 1000 RPM