Ask to do a crazy job

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I was called out to a customer today to look at a project. There is a machine that has 8 big stainless shafts. 42 feet long 14 O.D. They have two of these shafts that need the bearing surface welded up and turn back down. They would like me to figure out how to do this in the machine. We have really no way to take them out. The bearing surface is 3" O.D  I have a little room to work and i can turn the shafts by hand. Welding them is not the problem, but turning them down is where i am lost at. Should i try to hand grind them and polish them. Don't have enough room for a BOA. Any ideas????????
Reply:Originally Posted by Ag SpecialtiesI was called out to a customer today to look at a project. There is a machine that has 8 big stainless shafts. 42 feet long 14 O.D. They have two of these shafts that need the bearing surface welded up and turn back down. They would like me to figure out how to do this in the machine. We have really no way to take them out. The bearing surface is 3" O.D  I have a little room to work and i can turn the shafts by hand. Welding them is not the problem, but turning them down is where i am lost at. Should i try to hand grind them and polish them. Don't have enough room for a BOA. Any ideas????????
Reply:Pictures would be a big help. Do you have access to the ends of the shaft?How true/flat is the rest of the shaft?How will you support it while machining the bearing surface?What is this thing inside?Grinding or sanding could work but I wouldnt do it by hand.Or you could call these guys, they will figure out anything if you have the cash!www.inplace.comYup
Reply:This is what I have seen done before, but could you find the space to use it.I have seen shafts of all manner both the suface and the bearings surfaces machined in-placeAnd yet another way to do it, also in the machine, without turning the shaft. http://www.inplace.com/machining/dow...bishment.html#Last edited by Burnit; 05-02-2008 at 09:51 PM.Yup
Reply:I will keep you posted zap. It is going to have to be done in the machine. No questions ask. The building was put up around these three machines. I have an idea, but just not sure if i can pull it off. I have a real good machining background, so i know what it is going take for carbides to turn weld off of this shaft. I also thought of a spray torch, but can't find anything from stoody on ss material.
Reply:Thanks..Definatly..I gotta see this..But I deal in half thousandths tolerances on some shafts and bearing surfaces need to be round..Good luck and keep the pics coming.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:They make portable lathes that will turn in situ. they actually turn the tool bit around the shaft. I think it is Climax and maybe some one else.They rent the equipment as well .  There are also guys who specialize in repairing seal fits on semi axle trailers. they can turn machine shafts in place as well..but the best you could hope for in that situation , would be .005/.010 concentricity.  Cut holes in the sides of the building.Good luck and take picturesinsert thoughtful quote from someone else2000 Thermal Arc 300GTSW 3.5 hours1946 Monarch 20 x 54 Lathe1998 Supermax 10x54 Mill2004 Haco Atlantic 1/2" Capacity Lasernot mine but i get to play with it
Reply:Part of the problem is having a 42' long shaft that's 14 " in diameter with only a 3" bearing OD. I don't think very much of stainless steel as a bearing surface anyway. That's a bad design, IMHO. I'm certain you could weld them but cleaning up the weld to have a decent tolerance would be another issue with the shafts left in place. I'm no professional but without the ability to grind the welded area to make a perfect fit on the bearing, I'd probably take a pass on that job. I think Zap has nailed it. Good luck.
Reply:The crankshaft journals in large engines, such as those used in ships, are ground without disassembling the engine.  Might be worthwhile to investigate how that's done.  Second choice might be to knock the smallest hole in the roof or wall necessary to remove the shafts.
Reply:I'll wish engineers would start thinking about how stuff is ever going to be repaired. I've had to do the hole in the roof and big crane trick twice in a year. I have 2 more jobs in the next few months that are looking like roof or wall mods will be in order.
Reply:At what speeds do these turn? If its a slow machine I wouldn't be afraid to do it in place. You guys should go to a gravel quarry sometime. You will see that anything is possible.
Reply:Roofs and walls are easy to fix, and have more forgiving tolerances.
Reply:daddy nailed itThe difference between art and craft is the quality of the workmanship. I am an artist.
Reply:Originally Posted by daddyRoofs and walls are easy to fix, and have more forgiving tolerances.