Someone exlpain "split point" drill bits please...

[redfishsc]

You'd think a cabinet maker would understand this but I don't.

Here's what I know of split-point drill bits.

1) My DD 300 won't sharpen them. Only make them look and perform crappy.

2) They seem to cost more.

3) They are almost always 135-degree bits which my DD 300 can't handle anyway.



What do they mean by "split point" and why is it beneficial?


Any info is helpful!

Matt

 

[its_virgil]

My DD 750 (I think) sharpens both 118 and 135 and does split point. I sharpen all of my bits to split point...the cut easier, cleaner, and don't seem to follow the grain as much....I like them. But, you asked to explain tehm to you...sorry, I can't. But, maybe this article can. Hope so.
http://tinyurl.com/kchfd

Do a good turn daily!
Don

Originally posted by redfishsc
<br />You'd think a cabinet maker would understand this but I don't.

Here's what I know of split-point drill bits.

1) My DD 300 won't sharpen them. Only make them look and perform crappy.

2) They seem to cost more.

3) They are almost always 135-degree bits which my DD 300 can't handle anyway.



What do they mean by "split point" and why is it beneficial?


Any info is helpful!

Matt

 

[KenV]

When you look at the tip, especially with magnafication, you will see that the split tip bits are reground so that the grind line split the area where the two flutes come together. The attribute is claimed to reduce the tendency of the bit to slate off track and start a more clean hole. As I remember the bit geometry, the grind through the point comes on the back side of the flute extending through what would be the point on the tip from the normal grind. The value of split tip is positive on steel and minimal on wood and other soft materials like acrylics, polyester resins, etc.


The 135 degree angle is less agressive and will cut slower. Cutting less agressively is generally good on pen blanks.

 

[KenV]

P.S. Don, it is probably more the 135 degree angle and really sharpe edges that make for straight drilling. The split tip does not hurt.

 

[Rifleman1776]

I use the DD500 and grind to a split point. I use the split point only because so many here, and other forums, reccomend it. I really can't tell the difference betwee the sp and regular with wood and don't do enough metal to speak with experience. The Drill Doctor is a valuable tool in my shop. The important factor is sharp.

 

[OSCAR15]

I prefer brad points because they don't wander as much. Yeah they can split blank easier, but I take it slow, backing out frequently to clear chips..Never really had a problem,,,,