Kirk, Do you chamfer the hole with a 90° chamfer to the OD diameter before tapping? Even with hand tapping this is standard practice to prevent the 1/2 thread from forming.
John On 2 Jul 2008 at 15:55, Kirk Wallace wrote: > On Wed, 2008-07-02 at 16:37 -0500, Chris Radek wrote: > > On Wed, Jul 02, 2008 at 02:12:17PM -0700, Kirk Wallace wrote: > > > I did my first rigid tap on my lathe. It worked well the first > > > time. (Thank you, developers) There is one minor problem. There > > > seems to be a burr left behind about 1.3mm (.050") into the > > > 4-40UNC hole. I shifted Z in my g-code to see if it would move , > > > and it didn't, so I think it is independent of EMC2. I have to run > > > a tap through by hand to clear it, so I suppose if I run g33.1 > > > twice, that should fix it. I would rather not do that, so has > > > anyone had this problem and fixed it? Thanks. > > > > What kind of tap are you using? Can you take a picture of the > > problem? > > > > By shifting Z do you mean you tried starting the G33.1 higher > > 'above' the hole? > > Sorry for not being clear. I started the g33.1 farther away from the > hole, thinking that if the fault where because of a motion or the tap > the fault would move the distance of the new starting point, but the > burr stays near the opening of the hole. I tried running g33.1 twice > (..., g0 x0.0 z-1.0, g33.1 z-1.4 k0.025, g33.1 z-1.4 k0.025, g28) and > this cleared the problem. I think slivers are following the tap as it > retracts the first time, and are left in the threads as the tapered > part of the tap leave the hole. When, I thread a screw in, the slivers > bind and anchor, instead of getting swept out. With the double g33.1, > the beginning threads seem to be slightly looser (my imagination > maybe), so I ended up clearing the threads by hand while the next part > runs. If I can figure it out, I should have a youtube of the part > being made soon. > > -- > Kirk Wallace (California, USA > http://www.wallacecompany.com/machine_shop/ > Hardinge HNC/EMC CNC lathe, > Bridgeport mill conversion, doing XY now, > Zubal lathe conversion pending > Craftsman AA 109 restoration > Shizuoka ST-N/EMC CNC) > > > ---------------------------------------------------------------------- > --- Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! > Studies have shown that voting for your favorite open source project, > along with a healthy diet, reduces your potential for chronic lameness > and boredom. Vote Now at http://www.sourceforge.net/community/cca08 > _______________________________________________ Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------- Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
