- Joined
- Aug 6, 2013
- Messages
- 334
Almost looks like there is a sleeve in the hole in the photo... Incorrect speed, dull bits or incorrect bit angle will cause excessive friction and heat. Aluminum is "gummy" when cutting and drilling and chip evacuation is important. A sharp bit and peck drilling and lifting the bit out completely each peck while using a coolant or cutting oil will keep the bit cool and avoid the issues it looks like you're having.