Gentlemen, I walked into a booth at IMTS a few cycles ago. This booth was a cutter manufacturer touting the shrink fit tooling and heat shrink machine they manufacture. All the propaganda focused on how the shrink fit process holds the tool better than any other method. As I was looking at the line of cutters in the display I saw an end mill with a spiral groove on the end of the shank portion. I asked what that was for. I was told this was developed to prevent the cutter from being pulled out of the adapter during high speed cutting. It also prevented cutter spin in the adapter. I have never owned or tried shrink fit tooling. I have wasted my money on the so-called "hydraulic" collet holders. The holders' performance was an absolute joke. The ONLY non spinning/pullout end mill holder(adapter) I have seen is a mechanical (ie weldon) style. I will say my high speed experience is limited to a 14,000 rpm 50 taper spindle but if the cutter manufacturer had to develop a mechanical slot to prevent spinning/pullout maybe the focus to prevent spinning/pullout should be mechanical even at the bridgeport level. Just sayin HTH Stuart
On Thu, Nov 10, 2022 at 2:34 AM gene heskett <ghesk...@shentel.net> wrote: > On 11/10/22 02:48, John Dammeyer wrote: > > > >> From: gene heskett [mailto:ghesk...@shentel.net] > >> It works well John, on the go704. I'd like to come up with a qcth holder > >> for them on the Sheldon as it has the torque to drive much bigger taps > >> but haven't quite figured out how to make such a critter, plus the > >> sheldon has no gibs to constrain the carriage from being lifted clear of > >> the ways when huge gobs of the torque reaction comes into play. I'd need > >> to hang another 30 lbs on the back end of the crossfeed to contain that > >> for say a 3" tap. That in any event even though I have the tap that big, > >> is a g76 job. But at a 3" size, I'd be longer shaping the boring tool > >> that doing it, my CBN wheels are quite fine, 2500 grit but fine is also > >> slow, fragile and expensive. > > > > Hi Gene, > > I'm mostly using the TTS holders and some of my more expensive tooling > is still R8 so I'm not converting over completely. > > > > I'm thinking that your approach with 4 set screws to hold the tap might > work well with TTS holders. A custom holder with a hole for the tap shank > and 4 set screws keeps the tap from turning. > > > > Now we're back to the original question I posed. If this TTS holder > with a 3/4" shank into the custom R8 holder with say 20 ft-lbs torque on > the drawbar won't turn then it's fine for tapping up to the tap size. > Since the TTS come with at least 1/2" holes it makes for a reasonably large > tap. Up to 7/8" shank which is once again listed as the limit for R8. > > > > And it makes the tap holders a lot less expensive than using ER20 > collets which are only good up to a certain size. Purchase a TTS for 1/4" > shaft, mount in a lathe collet and bore to the size of the target tap. > Drill the 4 holes and tap them. Now it's a TTS Tap holder. > > And I'm having a hard time visualizing that, can you scribble up > something and put it on your web site? > > > If one wanted to modify the spindle it would be possible to put a pin > hole just outside the diameter of the TTS tool. Then modify the TTS tap > holder to have a flange like the pin on your holder that goes into the > collet. > > > > In fact, modify all the TTS holders to have the flange and it's possible > to prevent all TTS tools from spinning in the R8 holders. Not only that > but the M66 command can put the pin in the same place so installing TTS > indexed tools becomes trivial. > > The word flange is confusing me unless its used to establish a constant > length to put in the tool table as TLO. And that would still be subject > to error from inconsistent tightening of the drawbar. > > My next mechanical thing on the go704 will be stripping a 1/4 ratcheting > screwdriver motor out, and rigging it on old 3d printer screws to > reengage/disengage from the drawbar, It has the torque I think, to break > the drawbar or strip its threads in left to hammer the bar for more than > 1 or 2 seconds. Then rig M6 to run it for tool changing, possibly from > mid gcode file. I use the drywall screw driver to do that now but need > more hands, one to run the driver, one to hold the spindle still, and > one to catch the tool when it comes free. By my count that's three > hands. :o) Needs more thought... > > > > John > > > > > > > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > . > > Cheers, Gene Heskett. > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author, 1940) > If we desire respect for the law, we must first make the law respectable. > - Louis D. Brandeis > Genes Web page <http://geneslinuxbox.net:6309/> > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Addressee is the intended audience. If you are not the addressee then my consent is not given for you to read this email furthermore it is my wish you would close this without saving or reading, and cease and desist from saving or opening my private correspondence. Thank you for honoring my wish. _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
