One of the most difficult aspects of boring is attaining the correct RPM for the cutting tool. Boring heads are design to move off center so you can enlarge the ID of a hole. This movement creates an imbalance which requires a slower RPM to ensure the bore can be produced. There are a number of approaches for correcting the imbalance. Some manufacturers restrict the amount of off-set so the boring head has minimal imbalance and others have some form of movable weights.
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CB-202B Boring Head with Balance Kit
US Patent 7,309,194 B2 |
Criterion had a unique situation because we had been producing boring heads for over 65 years. Our philosophy was to give our customer as large a boring range as possible with one boring head. Time has changed manufacturing technology and higher speeds have become important. We did not want to limit the range but we did want to meet the needs of today's manufacturing. Our solution was to develop a unique balancing system for our 202 series of boring heads. The US patent office agreed and issued a patent for the system. So by looking up your bore size, selecting the correct components and settings a boring head made over 50 years ago can spin at 5,000 RPM. This was unheard of when the boring head was first made but very achievable today.
So I would say the adage of "you can't teach and old dog new tricks" is not true.
What is the value of a balanced boring head? First and foremost is increased productivity. Another benefit is improved tool life because the cutting tool now can operate at its optimum speed.
