There is a custom adjusting screw that I buy commercially and when I get them the threads have a text-book geometry to them. That is, they have a small flat top on the major diameter and small flat bottom at the minor diameter or root. They are made to class 2 or perhaps even class 3. I know that these screws I am getting commercially are made using single point carbide insert tooling on a cnc lathe.
I want to make a few of these myself and am cutting them using G76 canned cycle on my Emco lathe (I have encoder on spindle, etc) using an Iscar carbide insert 16ER A60 (link below). These are 3/8-24 thread and that falls in the range of the TPI supported by the insert. We have spent time making sure we have the tool lengths, etc dialed in as precisely as possible and are trying to be very careful with our major diameter and thread depth, etc. When measuring the threads we are within specification in terms of pitch diameter and major diameter, etc but the geometry of our thread is very pointy. That is the major diameter peaks are pointy (almost to the point of being sharp) and the root appears to be quite pointy as well, seems to be exactly like the pointy tip of the insert. So, the threads work fine for the purpose but the geometry is bugging me. By the way, this seems to happen for nearly every thread I have cut on the machine, but I haven’t cared as much in the past as the screws have been for my own purposes, but this one will be used in a product sent to customers. I am wondering if I am doing something wrong with the insert I am using or what. Any thoughts? Iscar insert: http://www.iscar.com/eCatalog/item.aspx?cat=5901944&fnum=113&mapp=TH&app=193&GFSTYP=M -Tom ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
