On Sunday 05 November 2017 07:51:20 Mark wrote: > On 11/05/2017 05:07 AM, Gene Heskett wrote: > > And where can I src from here in the US, a decent quality, 10mm 1.5 > > pitch, solid carbide spiral machine tap? Ebay's search engine and > > the sellers have no clue that there is a difference between HSS and > > carbide, using both words to describe the same item, nor what the > > difference is between a spiral tap and a spiral point. And neither > > do the sellers. :( > > > > Thanks guys. > > > > Cheers, Gene Heskett > > https://www.mcmaster.com/ > > https://www.mscdirect.com/ > I was there in the night. What I want was somewhat north of $80 a pop. So I'll see if I can get the last hole done with this one. Thats including shipping of course.
I may investigate my dremel stuff to see if I have a cylindrical stone of the right size to sharpen this one. I did that once, probably 50 years ago with very good results. > If ya buy cheap Chinese crap, ya get cheap Chinese crap. That goes without saying. Basically its getting better, but QC still leaves a lot to be desired. Those $15 for a ten pack of carbide inserts from banggood are working well, and lasting at least as long as some of the $15/chip stuff though. That surprised me, a lot. I also found my missing bag of microswitches, in the basement with the 74ls04's. So I can get back to work on that. And I have some PID tuning ideas to check out because it was running in a single gear only, very well it terms of responding to loading variations. In fact that is how I tuned TLM, rather than disturbing the set point, I disturbed it with a leather belt wrapped around the chuck, which takes the chucks mass back out, where by cycling the set point it has to manhandle the mass of a good sized chuck, which for TLM is a 5" 4 jaw, two entirely different sets of characteristics. It makes sense to me that for a velocity servo, FF0 should be brought up to a zero or slightly negative error, with the spindle running just a few percent faster than the commanded setpoint. This might be close to 1.0 in high gear, but close to 2.0 when the backgear is engaged. Then Pgain brought up from zero until it responds quickly to a load disturbance, holding the error as close to the setpoint as it can and still stabilize. Then the mass of the chuck on the mill is far less important than the mass of the motors spinning armature, which in backgear, if if follows the E=mv2 law, is at least 4x what it is in high gear since its turning 2x faster in low for the same spindle rpms. The idea is that setpoints won't change during a given operation, other than the reversals for G33.1's, but loads can change, a lot. And its loads that need the compensation of lots of Pgain. This is made difficult by the differences in load we see when the tap actually starts cutting, and is IMO much more important. I had an Igain windup so bad that when I finally broke it loose so it would reverse back out of the hole, it over sped z and threw a following error. With the smaller, much lower inductance motor on the mills Z, it can now move at 70 ipm upwards. That motor and driver are now on the Sheldons Z screw, and while the same limitations would apply there, the spindle of the Sheldon is trotting right along at 300 rpms. It will be interesting to find out how fast it can reverse a chuck thats about 1.25" bigger and weighs another 15 lbs. The existing 3 jaw makes the belts yelp. But not until I make another lock clamp. This plates rear hub is big enough that a single ring can probably be attached to the rear face of the hub, and clamp directly on the spindle flange. The smaller 3 jaw locker is in two coupled rings, one clamping on the hub, and the other on that flange. Much easier to make this one. My 1/2" thick hard alu stock will need a step cut in the rear to clear the spindle bearing hardware since the flange is only about .275" thick and the bronze bearing is about an eighth bigger dia. The 1/2" thick stock leaves me plenty of room for a substantial 5mm draw bolt. It works well on the smaller chuck, don't see any reason it won't on the larger, heavier yet chuck. But I'd better git-to-it. Thanks for reading this far. > Mark > > ---------------------------------------------------------------------- >-------- Check out the vibrant tech community on one of the world's > most engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > [email protected] > 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) Genes Web page <http://geneslinuxbox.net:6309/gene> ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
