On Thu, 2011-02-17 at 19:35 +0200, andy pugh wrote: > On 17 February 2011 19:19, Jon Elson <el...@pico-systems.com> wrote: > > > Probably the only way to > > do it would be to rigid tap with the plug tap, change to the finish tap > > but leave the holder loose and manually > > start it into the hole, and let the existing threads synch the tap. > > Then, tighten the tap holder while it is still > > in the hole. This is not what I'd call a reasonable shop operation. > > Once set up though, with indexed holders (such as BT, CAT, INT) it > should carry on working. > > However, this all seems a bit of a diversion from the original question... >
Since this thread has bird-walked from spindle orient to tapping I thought I would take the liberty of renaming. In all this fuss over how to machine tap no one has mentioned thread forming. The few times I've tried it by hand it has worked well. With small holes reaming to the starting size is recommended. It works well with CD 1020 which is not completely soft. tensile of about 70K. Tapping 304 SS might be a challenge but I've not tried it. I know of an emc-er that tapped some 800+ holes in A36 with a single tap. :-) All done with a portable drill. ;-) No swarf to worry about in the final op. just drill, ream to size and tap, reverse out and be done. Yes I know that involves an extra op but you get good threads right down to as close to the bottom as your guts will let you go. Obviously, there are limits to where this is practical but the method seems to be under-utilized. Just my tuppence. Dave ------------------------------------------------------------------------------ The ultimate all-in-one performance toolkit: Intel(R) Parallel Studio XE: Pinpoint memory and threading errors before they happen. Find and fix more than 250 security defects in the development cycle. Locate bottlenecks in serial and parallel code that limit performance. http://p.sf.net/sfu/intel-dev2devfeb _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
