-
Welcome back Guest! Did you know you can mentor other members here at H-M? If not, please check out our Relaunch of Hobby Machinist Mentoring Program!
Tips for removing a broken center drill?
- Thread starter Nelson
- Start date
- Joined
- Jan 22, 2011
- Messages
- 8,016
Nelson, there are a few "tricks", but they run from extreme to mildly amusing.
If the workpiece is suitable, slam it down against an anvil like using an impact bullet puller. Dents must be allowed here.
Take a OX torch and red heat the workpiece which anneals the HSS and drill it out.
Use a carbide end mill and cut it out slowly.
Special grind a hollow end mill and cut around it, then chip it out with a prick punch. Think reverse countersink shape.
If the length/depth (whatever) allows, cut off enough stock to get beyond the broken bit.
If the workpiece happens to be a stainless alloy, get some Tap-Out and dissolve it. Or if not stainless, deal with the staining and etching.
I'm sure there are a few other ways, but that's all that come to mind.
Is this lathe or mill?
If the workpiece is suitable, slam it down against an anvil like using an impact bullet puller. Dents must be allowed here.
Take a OX torch and red heat the workpiece which anneals the HSS and drill it out.
Use a carbide end mill and cut it out slowly.
Special grind a hollow end mill and cut around it, then chip it out with a prick punch. Think reverse countersink shape.
If the length/depth (whatever) allows, cut off enough stock to get beyond the broken bit.
If the workpiece happens to be a stainless alloy, get some Tap-Out and dissolve it. Or if not stainless, deal with the staining and etching.
I'm sure there are a few other ways, but that's all that come to mind.
Is this lathe or mill?
- Joined
- Jan 1, 2011
- Messages
- 305
Here's a great trick from that other forum:
Ground out the center section of the bit with a cut disc along the same angle as the cutting edges. Run it into the work piece and it cut around the broken tip.
Ground out the center section of the bit with a cut disc along the same angle as the cutting edges. Run it into the work piece and it cut around the broken tip.
Last edited by a moderator:
- Joined
- Apr 13, 2011
- Messages
- 16
If you can drill through the back, it can be popped out.
Another trick is to use sulphuric acid using a dam of modelling clay.
Another is to use a rod on a electric welder. You'll need at steady hand to join the rod and the tip end but it can be done.
Another is to make a hollow trepanning tool- out of carbon steel and temper it glassy hard.
Another from the days when I had a steady hand is to use a hard pointed drift to work round the sticking bit. It should crack but wear safety goggles.
Of course you should have a Quorn tool and cutter grinder to sharpen your centre drills. Oops, Naughty Norman
Another trick is to use sulphuric acid using a dam of modelling clay.
Another is to use a rod on a electric welder. You'll need at steady hand to join the rod and the tip end but it can be done.
Another is to make a hollow trepanning tool- out of carbon steel and temper it glassy hard.
Another from the days when I had a steady hand is to use a hard pointed drift to work round the sticking bit. It should crack but wear safety goggles.
Of course you should have a Quorn tool and cutter grinder to sharpen your centre drills. Oops, Naughty Norman
- Joined
- Jan 22, 2011
- Messages
- 8,016
Funny stuff.....the system thinks a p r i c k punch is a jerk punch. A translator!!!
- Joined
- Apr 13, 2011
- Messages
- 16
Actually, the centre drill as the start to a drilling or boring operation can be dispensed with so long as you use the 'four facet' method of re-grinding drills.
I almost think that this is an 'English' thing but 'GadgetBuilder.com' has quite a lot on the topic.
I almost think that this is an 'English' thing but 'GadgetBuilder.com' has quite a lot on the topic.
Similar threads
