Posted by Raymond Anderson on 04/09/2016 18:31:49:
Nick, Have to disagree there. They were originally designed for toolholding, more specifically Drills / reamers. I use them for a lot of workholding as do many others and they are great , but workholding is not what they were designed for. There are far better collets than ER for workholding. even as a milling chuck they are far from the best , they are super at taking axial loads, but not at their strongest with Radial loads. I like them but am not blind to their shortcomings.
cheers
Sorry Raymond but how do you work out that a collet tightened up onto work one side and two tapers the other side cannot accept radial loads ?
Surely the limitation will be the collet holder or machine bearings and as Neil has pointed out milling loads in the axial plane are far higher.
I do so hope this is not one of those urban legends that gets repeated over and over with no fact.
Edited By JasonB on 05/09/2016 12:46:07
Is a standard, 3-jaw chuck or a collet chuck a better choice for your CNC turning machine? The answer is (as is true with so many decisions): It depends.
The advantages and disadvantages of each type of chuck must be considered in terms of your application lot sizes, range of material diameters, types of materials, length of workpieces, and dimensional tolerances, among other issues. Here are some facts to think about:
Versatility. If you’re running a number of different jobs with a variety of workpiece diameters, 3-jaw chucks may be the right choice. Collet chucks are best suited for smaller diameter workpieces, typically 3” or less. 3-jaw chucks are also better suited for machining longer workpieces because the longer collet chuck limits Z-axis travel.
Spindle performance: Because they are lighter in weight, collet chucks have less mass, so the lathe spindle gets up to speed faster and puts less strain on the spindle motor. Additionally, the lighter collet chuck enables handling of heavier workpieces at higher spindle RPMs.
Tight tolerances: For high precision work, collet chucks maintain equal clamping force around the workpiece, rather than at only 3 points and, therefore, are less affected by centrifugal force. This provides for better concentricity and greater accuracy.
Changeovers. It all depends on your application. Collet chucks generally require less time to change, however 3-jaw chucks accommodate a greater range of diameters without requiring changeovers.
Of course, there are a number of other issues to consider when deciding which type of chuck to use – as well as other factors that affect CNC machine productivity. The applications engineers at Gosiger can help. For more than 95 years Gosiger has served CNC shops with unmatched customer service and support. To learn more contact your nearest Gosiger facility.