On Saturday 20 March 2010, Dave wrote: >On 3/20/2010 2:12 PM, Gene Heskett wrote: >> On Saturday 20 March 2010, Paul Keeton wrote: >>> Gene, >>> >>> Do you (or anyone else) see any any issue with using a >>> separate encoder and leaving the tach on the motor alone? I have seen >>> this done on other servo systems with great reliability. Normally >>> backlash is not an issue unless it is an excessive amount on those >>> systems. You simply don't use backlash comp if there is a scale on the >>> machine. You may have to if your encoder is on the screw. Almost >>> definitely if your encoder is on the motor and you have a gear box. I >>> would have to agree about the lag time. What would you suggest? And by >>> the way, I sensed no disrespect, I asked a question and you respectfully >>> responded with an intelligent answer, and I thank you for that. >>> >>> Dave >> >> I believe there are several here who are using the tach signal back to >> the motors controller, and the encoder output then going back to emc, and >> it apparently works quite well. But I should let those who are do the >> testifying that it works well. >> >> I can't personally testify to that as my only machine is a thoroughly >> hacked, all new Z axis saig x1, with 262 or 425 oz steppers on it, aka >> the smallest HF they sell, with bigger tables and the rebuilt z, it does >> pretty well if I can keep the damned typos under control. >> >> It missed the first 0 after the decimal point yesterday and carved a hole >> in the side of the barrel channel of a gunstock I first carved by hand 40 >> some years ago. So now I have some thin strips of walnut being glued up >> to make a plug for it after I squared up the hole, the original blank was >> about $130 in 1969. With a little luck, it won't be too noticeable once >> its fully refinished. That is basically what I was doing anyway as I'd >> pulled the Rem 788 action and its 2nd shot out Shilen 22-250 Barrel and >> have refitted it for a heavy SS Howa 1500 in 22-250. >> >> [...] > >Yikes. That was probably painful to look at after it happened. >Sometimes you just can't to the Estop fast enough. :-( > >Dave > Pretty much Dave. The air was quite thick and blue for about 10 minutes in the shop. The real problem is that the walnut I have on hand to lay up the new laminated piece is probably 20 years newer and still has that 'you can taste it' milk chocolate color, whereas the 40 year old stuff is noticeably more off toward amber colored. I set it about 10 thou proud on the visible side, and will see how well I can do at gently removing all of that 40 year old finish that I was just layering up some more with some of Sam's stuff. Once that yellowed finish is back to bare wood at 600 grit, the color diffs might not be so obvious. That diff might be so obvious I might be taking it all off and starting over. I would like at some point if I can get my hands on a small block of it, to make a grip cap and fore end tip out of some 200 year old Bullet wood they are fishing out of the rivers around Belize, if they can ever get it dry. 2, 2 week sessions in a vacuum kiln haven't gotten it under 20% moisture yet. The stuff is nearly petrified after 180-200 years in the river bottom mud, very dense and very hard. Its nearly blond, with the craziest grain, I've never seen even fancy maple that well figured.
I could use cherry, I have plenty of that, but its nowhere near the color contrast I'd like. Or even maple, I have some of that which has drying now for over a decade, but nothing with real figure, at least that I've uncovered yet. Lots more of that in the shed though. I tend to grab that as I go by a little woodshop up in NY. At prices 50% less than market usually. :-) -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) The truth you speak has no past and no future. It is, and that's all it needs to be. ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
