- Joined
- Mar 25, 2013
- Messages
- 4,653
Hmmm...seems to me that if you use the 90 deg and drill larger than the final hole you may as well just use a center drill and do the same thing. I think I have a lot of 135 deg drills so I may need the 140 deg spotting-hard to find.
I am also noticing this: the cobalt steel drills (what I like to use) almost always come as a 130 or 135 deg tip. I never noticed that before. Apparently there is more science to this than I was aware.
This is from McMasterCarr:
"135° Point Angle—Perform better than 118° point angle bits on hard materials and produce smaller chips to prevent clogging. They also have a split point that keeps the bit centered without a pilot hole and meet NAS 907 Type B aerospace specifications, unless noted.
118° Point Angle—Metric-size 118° point angle bits are made to DIN length specifications"
R
I am also noticing this: the cobalt steel drills (what I like to use) almost always come as a 130 or 135 deg tip. I never noticed that before. Apparently there is more science to this than I was aware.
This is from McMasterCarr:
"135° Point Angle—Perform better than 118° point angle bits on hard materials and produce smaller chips to prevent clogging. They also have a split point that keeps the bit centered without a pilot hole and meet NAS 907 Type B aerospace specifications, unless noted.
118° Point Angle—Metric-size 118° point angle bits are made to DIN length specifications"
R
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