On Tue, 12 Jun 2012 14:53:51 -0400, you wrote:
>But when it was about 90% cut, I noticed that the last thread against the >shoulder was obviously undersized because the actual retract motion wasn't >being done as fast as the -e=.009 was giving it. Thinking on that, it made >sense to reset that to about -e= to about .020, or slightly over half a >revolution. So I did, and while the damage had been done by then, it at >least didn't make it any worse by the time I had achieved the desired tight >fit into the breech plug itself. You're never going to get a full thread all the way to a shoulder. Two methods of getting around that are a relief groove up against the shoulder, or a counter bore in the female thread. They don't need to be large, only deep enough for thread depth and 1 pitch - that's easy on the female thread, but not so on the mail thread with the shoulder in the way of the insert. Usually my CAM program works out the width/depth of the relief groove or how close I can get to the shoulder without gouging it with the flank of the insert or tool holder. It does a pretty good job most of the time getting awfully close before retracting, occasionally not - likely my fault being sloppy with touching off :) >I've just spent a couple hours searching for what looks like a better deal, >but if I want a ball screw, it is the nut I'll have to turn by attaching >the screw to the crossfeed sled, and turn the nut, mounted in bearings much >like I did the Z drive for my mill. Not only bulky but adding unwanted >weight to the rear of the carriage. Sigh... I wouldn't worry about weight on the rear of the carriage, with front tool posts it's always wanting to lift the back - more weight may help counter that some. Steve Blackmore -- ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
