- Joined
- Sep 24, 2012
- Messages
- 495
I've been tinkering with a very small machine shop for several years, but I'm a perpetual newbie. My question is about what point angle I should use for my everyday drills.
OK, I've been in the habit of buying 135-degree split point for all my drills, mainly because they seem to be sturdy and resist walking during the first moment of entry. Most of the time they perform beautifully. Actually, all the time, really.
My question is about those times when I need to drill a small hole in a very controlled, precise location. I have a set of combined drill/countersink to locate a tiny hole into the material, and then follow with the actual drill bit. I should have thought of this a LONG time ago, but I just realized that the cutting angle is LESS than my 135-degree drill bits... I'm not sure of the angle, but they look like about 60 degrees. So when I press the drill bit into the hole made by my combined drill/countersink, my drill bit is not going to immediately hit bottom, right?
If I'm going to use 135-degree split point drills, what should I use to make my initial hole? Whatever I use needs to make a larger degree-angle than 135 degrees, right? I know there is such a thing as spotting drills, but they look just like normal drills... if I'm going to use those, what's the difference between (1) making a pilot hole with a spotting drill and following up with a normal drill, and (2) just making the entire drill hole with the spotting drill? I mean, if the spotting drill is so superior with making the original hole, then why not just finish the hole with it?
What am I missing? You can tell I'm confused....
OK, I've been in the habit of buying 135-degree split point for all my drills, mainly because they seem to be sturdy and resist walking during the first moment of entry. Most of the time they perform beautifully. Actually, all the time, really.
My question is about those times when I need to drill a small hole in a very controlled, precise location. I have a set of combined drill/countersink to locate a tiny hole into the material, and then follow with the actual drill bit. I should have thought of this a LONG time ago, but I just realized that the cutting angle is LESS than my 135-degree drill bits... I'm not sure of the angle, but they look like about 60 degrees. So when I press the drill bit into the hole made by my combined drill/countersink, my drill bit is not going to immediately hit bottom, right?
If I'm going to use 135-degree split point drills, what should I use to make my initial hole? Whatever I use needs to make a larger degree-angle than 135 degrees, right? I know there is such a thing as spotting drills, but they look just like normal drills... if I'm going to use those, what's the difference between (1) making a pilot hole with a spotting drill and following up with a normal drill, and (2) just making the entire drill hole with the spotting drill? I mean, if the spotting drill is so superior with making the original hole, then why not just finish the hole with it?
What am I missing? You can tell I'm confused....