MadModder
The Shop => Tools => Topic started by: NormanV on May 05, 2017, 01:27:02 PM
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I have a number of end mills that have rounded corners. At first I thought that they were worn but on examining them with a magnifier they appear to be made that way. Am I mistaken or is this a standard item that I have never previously heard of?
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Norman -- Fillet corner end mills are commonly available.
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I have ground some end mills like this for counter boring and roughing. But i didn't know
this was an industry practice until recently ( " they : don't let me out much)
A sharp corner of an end mill is its weakest point. The corner radius design strengthens the end mill by reducing chipping and providing longer tool life. In mold applications where ball end mills have traditionally been used, a corner radius end mill will remove more material faster, improving productivity.
http://www.endmill.com/pages/cornrad.html (http://www.endmill.com/pages/cornrad.html)
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Thank you both, I thought it made sense to have the corner radiused as it is obviously a place that could overheat quickly. They also give a radius to an internal corner which will be good if it does not get in the way. When the time comes to sharpen them I'll probably just give them a sharp corner. (I need to get that cutter grinder built.)
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It's to stop 'stress risers' at the internal corners of milled work - generally good practice not to have a sharp corner if the design will accommodate a radius.