Drilling a perfect hole seems quite easy, but if you are not an experienced handyman this could be a potential problem. You get a suitable drill bit, attach it to the drill press, turn it on, and then just a slightest thing goes wrong and your hole is far from perfect.
Here are the 10 most often drill bit problems and the advice how to avoid them.
1. Broken drill bit
This is an issue that could literary happen to anyone. Know that it is not your fault. There are various reasons that lead to this issue:
- Worn outer corners
To avoid this from happening check your speed and if you are using the adequate coolant. Using the wrong coolant can lead to excessive run out as the drill breaches the metal.
- Clogged flutes with chips
To avoid this issue just use drill bits with wider flutes. You can also withdraw the drill bit at certain intervals to clear the chips away. In cases where the chips are not broken up, you can consider heavier feeds or a chip breaker design. In addition, you have the option of using polished flutes.
- Insecure holding of your work
Well this causes slipping which leads to sloppy holes. So clamp it down or use the appropriate holding equipment.
- Excessive feed
The solution for this one is easy, just reduce the feed.
- Too dull twist drill
Before starting the drilling process, check the drill bit it might need re-sharpening or replacement.
2. Drill bit slipping
Check if the chuck is holding your drill bit tight, if that is not the case try to use a drill bit with 3 flats on the shaft. This will provide better grip and avoid slipping.
Check out Drill bit types.
3. Damaged point angle
This could easily happen by simply hitting the drill into the socket (by metal hammer). To avoid this from happening, even if it is necessary use a soft lead instead (eg. plastic hammer). Also, be careful and do not mishandle the jobber drill.
4. Hole too large
You used the right size drill bit but the hole is too large.
- Your drill point might be off center so re point or replace it for additional accuracy.
- Adjust the machine spindle; it might not be running true or it isn’t rigid.
- And most importantly tighten your work!
5. Hole with rough edges
It is very disappointing when you get a hole that is rough around the edges.
To avoid this, re point or replace the jobber drill. The drill bit might be dull and the grind point incorrect.
Also, reduce the feed and use a proper coolant.
6. Breaks in outer corners
If the drill bit breaks in outer corners, first check and adjust the coolant, do not use excessive speed.
7. Drill bit wandering
This issue appears if you are using a standard 118° drill bit – to avoid it, use a split-point drill bit.
The issue can also occur due to the work surface, which does not provide enough friction. Again, use a split-point drill bit for better grip. This will reduce the wandering.
8. Chips not breaking up
If the chips do not break, they could become very long and stringy which could lead to wrapping around the tools. Then you have to stop your work and clean the drill bit frequently.
To avoid this issue from happening in the first place, increase your feed and adjust the style of the jobber drill and the point used.
9. Chips on the drill bit lips
There are two reasons for this issue:
- The first one is too much lip clearance – over 15° – this leads to the cutting lips to break down. To avoid this issue re point or simply replace the drill.
- The second one is insufficient clearance – under 9° – this requires additional feed pressure that causes the drill to split the web. To avoid this issue also re point or replace the drill.
10. Chipping of the cutting edge
This can occur due to a loose holder. So please check your holder, adjust it or simply choose another one.
It can also occur due to extreme cutting speed or feed. So please reduce your speed and feeds.