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  IMPORTANT ADVICE FOR MILLING HOLDERS
Article & Photos Provided by Big Kaiser
 End-mill-side-lock
Milling is a core operation in all kinds of manufacturing environments. There are five different kinds of milling holders, each
with their own strengths and weaknesses. Here is some information to help you choose with the breakdown and top recommendation for using each.
MILLING CHUCKS
Let’s start with the jack of all trades in the world of milling holders. Milling chucks’ high retention force combined with a simple twist-to-lock operation makes them ideal for general purpose operations. These chucks grip a tool shank by means of mechanical deformation of rows of needle bearings. These holders provide substantially more gripping force than a collet. Runout, however, is reduced compared to collet chucks, but is still better than double the performance of side lock systems. Their large bodies help dampen vibration and chatter. The
option for high-pressure coolant delivery through the tool is also useful.
TOP TIP
The bigger the milling chuck, the more the clamping force. Larger size chucks have a higher starting potential clamping force. When paired with a reduction collet the final gripping force is higher than a direct clamping size chuck.
HYDRAULIC CHUCK
Hydraulic chucks are often more specialized because of their slim body shape, higher cost and moderate gripping strength—about half that of a milling chuck and about double that of collet chucks. The main differences between the holders, in terms of performance, are the superior vibration damping and simpler handling of hydraulic chucks. They are most often used for finish milling, reaming and drilling. They are extremely easy to handle. A simple clamping screw activates hydraulic chambers that allow the holder to clamp down on the tool.
TOP TIP
Never exceed a hydraulic chuck’s rated rpm; fluid is pulled away from the holder’s internal gripping gland, causing loss of clamping force.
SHRINK-FIT HOLDERS
Often compared to hydraulic chucks because they can also have very slim bodies, shrink-fit holders share similar gripping force as well. Handling is much more involved, but from an engineering perspective, shrink-fit holders
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