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Today sucked,largish crash in the shop

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  • #16
    Just Clean it up

    Grind or hone out the boil and carry on should be OK.

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    • #17
      Sorry to hear about your wreck Darin. I have a friend that was doing the same kind of work and a piece of pipe came out of the chuck and hit him in the mouth. All he remembers is getting up off of the floor and wondering why his mouth was bleeding. It cut his lip pretty good but that was all that happened to him and it could have been a lot worse. I'm just glad you didn't get hurt. Take care.
      Jonathan P.

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      • #18
        I have never made a mistake. Today.
        Well, I better get off the computer and head out to the shop!

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        • #19
          I had to learn that one the hard way.
          4" sch 40, only about 4" long in a 6" 3 jaw.
          I forget all the other details but I must have gotten too aggressive with feed or DOC.
          I still remember that "clunk" and that piece of pipe flying over my shoulder.
          Twisted it right out of the jaws.

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          • #20
            Well I've been working at it all morning and so far it looks like we lucked out.

            First thing I did was degrease and hit it with dye penetrant looking for cracks.Nothing showed.Then I colored in the wear surfaces on the offending slot and ran the jaw it.It wiped in one spot on each side of the slot about 1" long.Quick check revealed that Bison leaves the chuck body around 40RC and induction hardens the wear faces to 60RC+.

            Some work with a diamond lap and a couple more trys on the fit and she cranks back togther.Still a little stiffer than before,but if it works it's okay by me.

            Checked all the faces of the master jaws no detectable deviation on any surface.

            A check with the Bison dealer we use shows the chuck body face as a replacement part at around $650.So worse that can happen is a new face will be bought.Chuck is nearly $1800 now wholesale.

            Fourjaw chuck,well maybe,maybe not.This was a sure enough 20hp motor grunting crash.The four jaw for this machine is semi-steel and 22".If the pipe had been in the fourjaw one of two things would have happened.Either the topslide would have been ripped off the machine or the fourjaw would have busted like a china plate.

            There is alot to said for forged steel chucks.
            I just need one more tool,just one!

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            • #21
              I guess I should have posted a few words about "safety valves".

              Some routine shop operaton carry higher risk than others. Insecure grip on lathe work is only one. In this case there is something to be said for lantern tool posts and rocker lathe tooling. Unllke a QC tool post which is so rigid its almost rooted to the compound a forged tool holder in a lantern tool post can be pushed aside in the event of a collision. There will still be some damage but it will be limited especially if the orientaton of the clamped elements are biased to lag the forces than lead, allowing a simple push-away.

              In the case of R/T over-runs there is not much that can be done except duck until the clamor stops. If the tooling etc is arranged to relieve or the grip on the work is such that it can safely dis-engage without exacerbating the damage then so much the better. I'm referring to a seldom considered aspect of machine work: defensive operation. Defensive operaton is where accidents and their likely origins are anticipated and escape/relief paths for the aftermath is provided.
              Last edited by Forrest Addy; 12-18-2009, 03:00 PM.

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              • #22
                A Ha! Another Pipe Man

                Originally posted by Black_Moons
                I believe pipe is extra dangerious because its not nearly as rigid as we would hope it to be, and easily flexes out of the jaws and distorts when clamped heavily leading to low clamping forces used
                Id go so far as to suggest if your really into pipe work, you don't use a 3 jaw or a 4 jaw, but a 6 jaw, Or at least make up a whole bunch of soft jaws for your 3 jaw chuck for exact pipe diamiters that grip the entire pipe so you can really wrench down on the clamping force.

                Those 'bull nose' pipe centers for tailstocks are also a big help

                I wonder if pipe is more secure to clamp from the outside or the inside?
                I second this advise!!! I had to work on tubing of all kinds of diameters and usually of cast acrylic or PVC. I made a set of "tall" soft jaws for the 3-jaw chucks on two of the lathes we had, the LeBlond and the American. Most of the parts only stuck out of the chuck about 12" in the worst case. My tall jaws were 6" tall and made of 6061 plate. I turned the inside and outside to fit the job, be it holding on the inside or outside. This gripped just well enough to be stable. Anything longer got a ride on the mandrel I made using a piece of 1" allthread and plywood disks turned to the inside diameter, held tightly by two aluminum plates and nuts. I would grip the outside of the tube or pipe, with the mandrel supporting the inside to stop distortion, and support the other end with a live center. Solid as a rock!
                Jim (KB4IVH)

                Only fools abuse their tools.

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                • #23
                  NOW somebody tell me how to securely hold a piece of UHMW in my lathe..

                  I spit it across the room with regularity. I am great at ducking.
                  Excuse me, I farted.

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                  • #24
                    Uhmwpe

                    Dawai...can't be much worse than teflon (TFE). You just have to hold your mouth right and take cautious cuts.
                    Jim (KB4IVH)

                    Only fools abuse their tools.

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                    • #25
                      I had a through the head threaded rod clamp drawed up.. draw it into a collet and tighten the crap out of it.

                      I need to turn hammer ends of various radius for the power hammer.

                      My machine has a LOO chuck.

                      That is some of the most slippery stuff to machine.. woodworking tools seem to work the best.
                      Excuse me, I farted.

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