On Sunday 07 February 2021 04:36:09 andy pugh wrote: > On Sun, 7 Feb 2021 at 03:29, Jon Elson <el...@pico-systems.com> wrote: > > want an R8 taper, vastly more tooling is available for it. > > Or, an NMTB30 taper, but that will > > make the holders more expensive. > > Not that much more expensive, and they are better in all respects. > > R8 only looks good compared to MT4.
I've got to agree with Andy, two things wrong with an R8, and I fail to understand why the #2 below hasn't been fixed decades ago by Bridgeport. They ISTR are the original proponent of the R8. 1. Any tool griping mechanism the has to squeeze a collet by drawing it lengthwise in a tapered seat has to compromise your tlo offsets in the tool table, if for no other reason than the battery fading in the impact screwdriver tool used to tighten the drawbar bolt. Or the lube on the drawbar bolts threads was changed or refreshed. 2. Unless you modify the open end of the R8 collet, cutting a notch to catch the head of a 4mm capscrew, as I did with my tap "hats" you also have random slippage of tap phasing mid-tap, wreckiung the thread/part and likely breaking the tap. And I don't care if you are built like the hulk, an ER32 nut simply cannot get an adequate grip on a tap shank, which seems to always be some random size, to stop that 100% of the time. As a user of numerous, not all alike, TTS style tool holders, I should put a similar locking scheme into effect for the 3/4" R8 collets. By putting a locator pin in the upper face of the TTS flange and a matching pinhole in the edge of the R8 collet, obviously timed to the pin slot in the collet. But it will take a carbide drill to make those holes, those collets are HARD, its all a coated carbide end mill can do to make the slot/cup for the capscrew in the tap hats. We, the users of this stuff, shouldn't have to customise our tool holders to "fix" these two problems. #1 if looking for ultimate, repeatable tlo accuracy simply is not fixable. Only with an ATS setup can that be fixed. But changing a spindle to the ATS/BTS format seems to cost more than the machine being converted. And the ATS toolholders seem to carry quite a premium price also. 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) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
