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  • #46
    Originally posted by The Metal Butcher View Post

    Whoops.

    Any particular reason for not holding that with outside jaws? I don't think that it would have chattered then.


    Today at work I fumble fingered the mic at the lathe and dropped it about a foot into the sheetmetal chip pan. Starrett 1-2, smooth finish, friction thimble. I emailed the inspection guy to let him know I may have knocked a calibrated mic out.

    Then doing some machining at home I had my mic sitting on the lathe saddle. Dumb place, I know. Starrett 1-2, smooth finish, friction thimble. Can you see where this is going? Except it didn't fall in the chip pan, it vibrated off to the floor. Hit hard, now reads 4 tenths out. I guess I bent it. Shame as the anvils will never line up quite right again. It was bang on on calibration and in prefect shape as well. There is my screw ups of today.
    I dropped my 1" digital mitutoyo Mic about 12 years ago. Landed vertically on the frame, and bent the lower anvil. I straightened it back out as best I could, and actually got it so I could measure a 1/2" tooling ball in various spots all over the anvil face with zero difference in measurement. It probably would have been fine for shop use at that point, but I sent it out to have the faces relapped. I think it only cost around $80 or so. There's a bit of chipped paint on the frame from where it hit (and where I used a big brass donker to straighten it), but other than that you'd never know. The anvils almost line up perfectly too, just a very slight finger catch on one side about a thou or less.

    Not sure I would have went through the trouble for a non digital, as they are so cheap and plentiful nowdays, but I'd just spent $250 on this mic a couple months prior......

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    • #47
      Something tells me this is going to turn into one of the best all time sticky threads, after a few years we'll have to check the percentage rate to Andy's "what did you do today" that way we can gauge and predict our oncoming failure rates of taking on a project, hopefully it doesn't totally paralyze the whole bunch and shut down the site lol

      Comment


      • #48
        Originally posted by The Metal Butcher View Post

        Whoops.

        Any particular reason for not holding that with outside jaws? I don't think that it would have chattered then.
        Other than not wanting to put the 4 jaw on and mess around with getting it somewhat centered. Then cut the ring off when 3/4 through, turn the piece around, recenter and finish the trepanning operation. I figured holding it in the 3 jaw for the entire operation would be less troublesome and faster. I'm probably off a bit on the faster part.

        Comment


        • #49
          [QUOTE=nc5a;n1924606]I've been doing a lot of trepanning lately and this screw up happened when I was machining a part for the my recently posted Tree Ram repair.

          Anyway, I needed a 7 1/8" X 1" thick disc to make a Tee ring. In my stash of treasures I had a flame cut 8" X 1" disc of unknown material (probably A36) that would do the job so I drilled a hole in it and bored it out to 1", made an arbor, ground a trepanning tool and went after it. As you might have already guessed it was tough going. Probably took me an hour or more including several tool sharpening stops. When I was done I measured the disc and it was 1/4" too small in diameter. I hate it when this happens.





          /QUOTE]

          Ditch the high rake on the tool, small wonder it chattered.
          I bet it was loud (-:
          If you do a lot of such work Kaiser/Thinbit make excellent modular insert tooling.
          http://www.thinbit.com/products/face-grooving/index.php

          Comment


          • #50
            Originally posted by Bob Engelhardt View Post

            Actually, that should satisfy your quota for some time.
            Man, I hope so! I actually don't screw up badly all that often, so I guess I'd been saving then up for quite sometime and released it all at once.

            Originally posted by Dan Dubeau View Post
            I dropped my 1" digital mitutoyo Mic about 12 years ago. Landed vertically on the frame, and bent the lower anvil. I straightened it back out as best I could, and actually got it so I could measure a 1/2" tooling ball in various spots all over the anvil face with zero difference in measurement. It probably would have been fine for shop use at that point, but I sent it out to have the faces relapped. I think it only cost around $80 or so. There's a bit of chipped paint on the frame from where it hit (and where I used a big brass donker to straighten it), but other than that you'd never know. The anvils almost line up perfectly too, just a very slight finger catch on one side about a thou or less.

            Not sure I would have went through the trouble for a non digital, as they are so cheap and plentiful nowdays, but I'd just spent $250 on this mic a couple months prior......
            Oof. I hope I don't have to do that. It was a favorite mic though. It's not our only one though by any means. I do want a digital mic someday. We have digital calipers and vernier mics. I like dial calipers and digital mics. Just be how it is somedays.

            Originally posted by nc5a View Post
            Other than not wanting to put the 4 jaw on and mess around with getting it somewhat centered. Then cut the ring off when 3/4 through, turn the piece around, recenter and finish the trepanning operation. I figured holding it in the 3 jaw for the entire operation would be less troublesome and faster. I'm probably off a bit on the faster part.
            I see. I would have chucked it in the 4 jaw, faced one side, drilled my hole and bored to whatever the inner ring dimension was, then flipped it, dialed my bore with the faced side against the jaws, then trepanned the outside of the ring. Then chuck the ID and turn the OD if needed. But that's just me. I hate stub arbors.
            21" Royersford Excelsior CamelBack Drillpress Restoration
            1943 Sidney 16x54 Lathe Restoration

            Comment


            • #51
              Well let's see, yesterday the very first thing I did was snap a M16 tap off in a blind hole. Luckily there was a enough sticking up that a nut and a little welding retrieved the remains.

              Then today, trying to spray some OHSA Short Bus (safety yellow) on a guard I had fabricated went horribly wrong. In my defense though, yellow is probably the most PITA color to spray. 875 coats later and it's still *almost"🤬
              I just need one more tool,just one!

              Comment


              • #52

                /QUOTE]

                Ditch the high rake on the tool, small wonder it chattered.
                I bet it was loud (-:
                If you do a lot of such work Kaiser/Thinbit make excellent modular insert tooling.
                http://www.thinbit.com/products/face-grooving/index.php
                [/QUOTE]

                Hey, thanks for the tip Bented. I had no idea there was such a selection of trepanning tools. I didn't check prices yet but I'm certain they would be quite spendy and very likely out of my price range but I will check just in case.

                With regard to the high rake and chip breaker trepanning tool I made. The one shown in the photo was my last attempt at tool profile to minimize the chatter and it actually worked quite well. It still chattered a bit but much less than my other profiles. Thanks for the link to Thinbits.

                Comment


                • #53
                  Originally posted by The Metal Butcher View Post


                  I see. I would have chucked it in the 4 jaw, faced one side, drilled my hole and bored to whatever the inner ring dimension was, then flipped it, dialed my bore with the faced side against the jaws, then trepanned the outside of the ring. Then chuck the ID and turn the OD if needed. But that's just me. I hate stub arbors.
                  Doing it your way I would have had to drill and bore a hole nearly 6" in diameter which wastes a lot of material. Most of us retired guys have to be more frugal. But I get what you are saying.

                  Comment


                  • #54
                    Originally posted by nc5a View Post

                    Doing it your way I would have had to drill and bore a hole nearly 6" in diameter which wastes a lot of material. Most of us retired guys have to be more frugal. But I get what you are saying.
                    Well, I didn't realize how thin the ring had to be. In that case, you could have saved the entire inner section by just tre-panning it out to that 6" out first. But I digress, it's done anyway.
                    21" Royersford Excelsior CamelBack Drillpress Restoration
                    1943 Sidney 16x54 Lathe Restoration

                    Comment


                    • #55
                      Originally posted by Beazld View Post
                      When I screw up I try to remind myself that we learn by our failures, not our successes 😑
                      If that is true I learned a lot lately!
                      Location: The Black Forest in Germany

                      How to become a millionaire: Start out with 10 million and take up machining as a hobby!

                      Comment


                      • #56
                        Not me this time but yesterday I was letting a buddy, a new guy to metal working use my lathe with tutelage.
                        He was doing fine so I left for one minute to grab another cuppa. Came back and he had put a nice 2 inch circular groove in the face of my chuck.

                        Faaaaaack.....

                        Comment


                        • #57
                          Originally posted by nc5a View Post


                          Hey, thanks for the tip Bented. I had no idea there was such a selection of trepanning tools. I didn't check prices yet but I'm certain they would be quite spendy and very likely out of my price range but I will check just in case.


                          I use ThinBit tooling often and they do an excellent job, small carbide tools are fragile as I am sure you know so care mast be taken (-:

                          Dovetail O-Ring groove tools are easily broken, I dislike the beasties in every way.

                          Comment


                          • #58
                            Originally posted by I make chips View Post
                            Not me this time but yesterday I was letting a buddy, a new guy to metal working use my lathe with tutelage.
                            He was doing fine so I left for one minute to grab another cuppa. Came back and he had put a nice 2 inch circular groove in the face of my chuck.

                            Faaaaaack.....
                            Should I say it serves you right? Nah. That would be a mean thing to say.
                            At least it was just the chuck and not the bed/ways/crossfeed etc. In other words it could have been a lot worse.
                            Next time pretend to trip and soak down buddy boy with the hot stuff.
                            Nah. That would be mean...

                            Comment


                            • #59
                              Too bad Sir John is no longer with us, this whole thread could be called Clumsy Bastard!
                              Sole proprietor of Acme Buggy Whips Ltd.
                              Specialty products for beating dead horses.

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                              • #60
                                I was doing some more work on my senior design project and blew the dimension on a 1" diameter of a 4.5: part. I will blame it on being distracted helping others. :P

                                I decided to try to weld it up to save the piece. Well, I was woefully unprepared for how much heat it took to puddle 1" aluminum. I was at 60% of the dial in high range on the 330A/BP, so that's somewhere north of 300 amps. I got most of it built up when everything went quiet and my tungsten caught on fire. I'd popped the 50 amp breaker. I knew that would be an issue, but dad wasn't going to do anything until it happened. Well, it has now. I tried again after letting it cool a bit, but didn't make it far before it popped again. I went ahead and roughed out a 6th part as I don't know if my welding will be successful and a 2nd spare doesn't hurt. Took less time than the welding did...

                                Any recommendations for keeping fumes away? Even just aluminum I felt kinda weird afterwards. Part of it is that I just get so damn nervous tig welding. I need to do it a lot more to calm my nerves. Or use the Russian approach...

                                No pics as my welds look like crap.
                                21" Royersford Excelsior CamelBack Drillpress Restoration
                                1943 Sidney 16x54 Lathe Restoration

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