On Thu, 9 Dec, 2021 at 4:32 PM, johnd <jo...@autoartisans.com> wrote:
To: enhanced machine controller (emc) Hi Gene. Would you measure and post the results please.I bought a very expensive spiral tap that I expected would meet ISO or DIN standards. Not!Another I have also doesn't. So I'm curious. Thanks John Now you've caught me in a lie, John. I have made tap hats for everything below 3/8" and could have sworn on a whole stack of bibles I had at least 3. But when I reached into the tray, I find I skip the 6mm's entirely, going from 5mm to 7mm's, no 6's. I didn't know there was a std, and I don't recall in being mentioned in #27 of the handbook. My experience has indicated that if there is an ISO or DIN std, its the most ignored standard extant. Tool makers are usually making them from stock no bigger than needed to contain the threads and its rare indeed to find a 12-24 tap with a 1/4" shank. So all I can say is measure the one you bought, and make a hat to fit it. I used 3/4" brass rod about an inch long, stuck a 4mm cap screw in the bottom edge that engages a notch cut in the end of a 3/4" R8 holder, so its absolutley locked to the spindle. Work wells considering the post of my go704 is not vertical. off topic here down. Thinking out loud IOW. If its trammed to the table it forces the tap sideways about 10 thou in a 3/4" total travel. So my holes are tapped sloppy. Come warmer weather again that post is coming off, the bolt holes get reamed and it gets re-installed a bit straighter. Its true, you get what you pay for when you buy a mill that size for $1100. cnc'ing it does not get that famous silk purse out of a sows ear. A lincurve module or 2 might fix it without all that. I learned a lot compensating for bed wear on the sheldon. Most of the error is x I think, but it might take some y too to fully correct it. All correction scaled to Z height of coarse. That's how I fixed the Sheldon to turn pretty good cylinders. LinuxCNC can do magic if you tell it to. So pardon me for thinking out loud. In fact a scaled Z and an offset per axis would do it _IF_ the post is straight and until I find different I believe it is. Now I need a piece of 3" heavy pipe to make a circular square out of. Cheapest I've seen one of those on fleabay is around $750. Cheers John & stay well. _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
