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Broken tap removal
- Thread starter Airpirate
- Start date
- Joined
- Aug 9, 2014
- Messages
- 106
Saw a note sometime back (possibly on this site) that freezing the tap with freeze spray then hitting it sharply with a pin punch will shatter the tap. You can then pick out the pieces. Freeze spray is available through any electronics outlet such as Digi-key. Broke a few 4-40 taps and this worked.
I went through similar pain with M3 tap in blind hole in aluminum (model radial engine crankcase). I had some hours into the part so went down the path boiling alum solution. It worked on Youtube so it must be true LOL.... alas but not on my tap. Happened to be a high quality chip ejecting tap & maybe the coating vs. plain HSS messed with the alum not working. Long story short the piece was wrecked in the process. You don't even have this option with steel.
Later on just for interest I peck drilled on it with an oversize carbide endmill. It was tough going but eventually removed the material. This would only be an option to then insert plug the hole & re-tap or maybe weld or something. Suspect EDM would be the best if it was cost effective.
BTW - this particular problem was my fault. Miscalculated the overhole too shallow vs tap depth. Even though it was chip ejecting, torque controlled tapping head, proper fluid.... shrapnel, especially sticky aluminum swarf, can tighten things up within a half turn & then its too late. Now for the critical holes in teeny sizes I use my own tap holders. Just made from O1 tool steel, slide in a collet at same drill position. A bit slower but they work perfect. You can feel torque & cutting pressures. Also get in the habit of blowing any chips out with compressed air & cleaning the tap before re-entering the hole on consecutive (tap cleaning) runs in the hole. Agree on quality taps & not skimping on used/dull taps. It wont solve all your problems but at least will eliminate some common ones.
Later on just for interest I peck drilled on it with an oversize carbide endmill. It was tough going but eventually removed the material. This would only be an option to then insert plug the hole & re-tap or maybe weld or something. Suspect EDM would be the best if it was cost effective.
BTW - this particular problem was my fault. Miscalculated the overhole too shallow vs tap depth. Even though it was chip ejecting, torque controlled tapping head, proper fluid.... shrapnel, especially sticky aluminum swarf, can tighten things up within a half turn & then its too late. Now for the critical holes in teeny sizes I use my own tap holders. Just made from O1 tool steel, slide in a collet at same drill position. A bit slower but they work perfect. You can feel torque & cutting pressures. Also get in the habit of blowing any chips out with compressed air & cleaning the tap before re-entering the hole on consecutive (tap cleaning) runs in the hole. Agree on quality taps & not skimping on used/dull taps. It wont solve all your problems but at least will eliminate some common ones.
- Joined
- Jul 2, 2014
- Messages
- 7,594
Call or visit a shop and ask them.
- Joined
- May 22, 2017
- Messages
- 47
Funny, I couldn't get the alum thing to work either. Scrapped the part.
Life is better with quality taps.
Life is better with quality taps.
- Joined
- Mar 25, 2013
- Messages
- 5,142
One thing I have done to save a part is to TIG weld the area of the hole. If it is not too deep you can create a puddle that alloys the tap fragment in to the surrounding steel. Then you can easily drill and tap the same location. This technique only works in some situations. The fragment cannot be more that about 1/4" deep and you have to be able to accept the distortion caused by welding. You may need to enlarge the hole above the tap fragment. Then melt the tap fragment, then use filler to get a flat surface. It can be done with good cosmetic and reasonable metallurgic results. Oh yeah, and it's cheap!
Robert
Robert
Go to harbor freight and get the small pneumatic hand piece die grinder and a pack of the diamond burs.
Get a few packs.
Lots of lube and air blasts and you can get it out.
Think like a dentist.
We have done this a few times.
If drilling holes with drill press then tap as next action before moving part.
Loosen motor drive so you can turn Chuck by hand.
Sent from my SAMSUNG-SM-G930A using Tapatalk
Get a few packs.
Lots of lube and air blasts and you can get it out.
Think like a dentist.
We have done this a few times.
If drilling holes with drill press then tap as next action before moving part.
Loosen motor drive so you can turn Chuck by hand.
Sent from my SAMSUNG-SM-G930A using Tapatalk