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  • Another day at the office.

    Been welding, a lot of welding for a long time.









    History of this is that the company the motor belongs to stripped it, bent the shaft trying to get it out and generally wrecked the rotor but it's so special a new motor is unobtainable at any price.
    There is a spline on both ends [ one is inside the chuck ] so they sent it out and had a new shaft made.
    Problem is whoever made it made the central section where the rotor fits 70 thou too small and it falls through.
    So sooner than have another new one made , can I weld this up without the shaft distorting ?

    So weld, then do an opposing weld to pull it back, then cool. repeat and rinse until done which basically took all day what with the cooling times.

    Chucked it up tonight to see just how bad, Zero at chuck end which is what is expected with soft jaws and 0.1mm [ 4 thou ] run out at the outer bearing end but if I run this diameter in a steady and single point the centre should get that to zero as well.



    That has saved the best end of 800 quid, must be able to get a pie and a pint out of that ?
    .

    Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.




  • #2
    Great job, as always. What is your welding setup for going round and round? Do it on the lathe turning slow or motorized fixture or something else?
    Kansas City area

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    • #3
      If I told you I'd have to kill you

      Actually built one of these a few years ago.



      Sorry it's a bit shaky.
      240 v DC motor driving a 60:1 reduction box which then drives another 60:1 reduction box and powered by a variac.
      Goes from zero speed to about 10 rpm flat out.

      How ever used it a couple of time but just don't get on with it, much prefer to weld one handed and turn with the other. so reverted to what i have before I built that.

      Behind the armature is a piece if 4" box section just visible. I have two of these about 6" high and they have a vee cut in the top with a hacksaw.

      That's it - real high tech innit. ?
      .

      Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



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      • #4
        So simple anyone could do it
        Peter - novice home machinist, modern motorcycle enthusiast.

        Denford Viceroy 280 Synchro (11 x 24)
        Herbert 0V adapted to R8 by 'Sir John'.
        Monarch 10EE 1942

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        • #5
          I hate welding shafts up,but if it has to be,it has to be,as long as the customer allows a dip in the deep end of their wallet

          Kinda looks like the shaft from a vibratory motor.
          I just need one more tool,just one!

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          • #6
            After you machined off the weld, did it maintain alignment?

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            • #7
              Not done that yet, Mondays job but I'm expecting no problems as it's had time between welds to normalise
              .

              Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



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              • #8
                How and where do you connect the ground (or perhaps it's the 'earth' on your side of the pond) when welding on any kind of turning jig? I am the most amateur of welders, so my ignorance level is high, but I've heard talk about "don't let current through the bearings, you'll fry them" and that sort of thing. There must be a best way?
                "A machinist's (WHAP!) best friend (WHAP! WHAP!) is his hammer. (WHAP!)" - Fred Tanner, foreman, Lunenburg Foundry and Engineering machine shop, circa 1979

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                • #9
                  If this is what retirement looks like, I am glad that I have no plans for it.



                  Dave

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                  • #10
                    Originally posted by mickeyf View Post
                    How and where do you connect the ground (or perhaps it's the 'earth' on your side of the pond) when welding on any kind of turning jig? I am the most amateur of welders, so my ignorance level is high, but I've heard talk about "don't let current through the bearings, you'll fry them" and that sort of thing. There must be a best way?
                    Dunno how Sir John does it, but I've seen a lot of welding done with a simple steel collar slipped over a shaft or a bolt. The collar has a tab welded to it for the ground clamp.

                    I've seen discussions about very heavy duty bushes on a shaft or even a loop of ground cable stripped bare hung on the shaft.

                    Some time back, I built a welding rotisserie from my scrap box. Simply a shaft running in two pillow block bearings. I put a collar/tab set up on a bolt and welded a nut on one end of the shaft. Welded a roughly circular drop of 1/4" plate to the other end.

                    If something like a shaft is done, I tack an angle iron s crap to the plate, and use a roller stand made with a couple lawn mower wheels.

                    Works for me. YMMV.
                    Last edited by camdigger; 03-08-2014, 02:53 AM.
                    Design to 0.0001", measure to 1/32", cut with an axe, grind to fit

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                    • #11
                      When running casing on the drilling rig the current passed through the rotary table bearings. I never saw any problems related to this.
                      Byron Boucher
                      Burnet, TX

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                      • #12
                        Originally posted by Boucher View Post
                        When running casing on the drilling rig the current passed through the rotary table bearings. I never saw any problems related to this.
                        It is just very bad practice to do, as bearings have a very limited contact area and thus those points act as resistance. Once you push the current through it, it can arc badly like in a spot welder.
                        Amount of experience is in direct proportion to the value of broken equipment.

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                        • #13
                          John,
                          What is the weld process you do these with, MIG, TIG, stick??

                          Just curious.
                          -Al

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                          • #14
                            Originally posted by Jaakko Fagerlund View Post
                            It is just very bad practice to do, as bearings have a very limited contact area and thus those points act as resistance. Once you push the current through it, it can arc badly like in a spot welder.
                            Some years ago I was trying to sort out starting problems on a rear wheel drive car and heard the current frying the drive shaft bearings. The earthing braid was broken, and the whole current was going through the drive bearings.

                            George

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                            • #15
                              A pie and a pint will soon be more than eight hundred quid If things keep going the way they are her John.The food is going up almost weekly in price.I do the shopping to Help Bronwen so I see it all the time fifteen pence here and there added every few weeks.I wonder where this is all going to go.The poorer are getting poorer and by poorer I mean a lot of elderly and young mothers with kids.I have an elderly friend who can no longer look after herself alone at home she is over eighty but all there in her mind she told Bronwen last week that a nursing home without nursing needs costs around eight to nine hundred pounds a week. I feel very saddened by these things. Alistair
                              Please excuse my typing as I have a form of parkinsons disease

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