Which Filler Rod?

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Not sure how this happened, but my shifter on my quad broke today. The shifter slides over the shaft and the splines on the shaft has a grove around it for the bolt in the actual shifter to pass in between the spines. The shaft broke right in the center. So i was going to try and tig weld it and see what happens. Worst comes to worst, i will have to tear the motor apart and replace the shifter shaft.  Is there a certain Filler rod i need to use for this? would a 70S3 or 70S6 work?Here are some pics... Attached Images
Reply:You might laugh at this, but I have repaired 3 that failed the same way. Best method I found was to silver-braze the parts together. Must be done fast to prevent overheating the seal. It has a lot of surface area, so brazing is almost ideal. The ones I did were a fairly high carbon steel, easily hardened. Yours was a fatigue failure so the steel is obviously not very ductile. Good Luck.
Reply:Originally Posted by makoman1860You might laugh at this, but I have repaired 3 that failed the same way. Best method I found was to silver-braze the parts together. Must be done fast to prevent overheating the seal. It has a lot of surface area, so brazing is almost ideal. The ones I did were a fairly high carbon steel, easily hardened. Yours was a fatigue failure so the steel is obviously not very ductile. Good Luck.
Reply:Why not tig it.Miller DVI2Lincoln Precision Tig 225Thermodynamics Cutmaster 38Everything else needed.
Reply:450r?not sure how you snapped that off, but if you did you may have already smoked something in the case. heck i only bent my shifter shaft after my boot landed on it, and the case seal was toast and so was the shifter fork."...My pappy was a pistol I'm a son of a gun...""...God is great, beer is good, and people are crazy..."
Reply:Originally Posted by jamlitWhy not tig it.
Reply:Hard to say, but my shifter shaft has never rusted, so take that for what it's worth. and it's been in the salty air for 5 years."...My pappy was a pistol I'm a son of a gun...""...God is great, beer is good, and people are crazy..."
Reply:Originally Posted by MustangousThats what i wanted to do, thats why i am asking for suggestions on filler rod, but makoman brought up a good point about heat, i dont want to ruin the seal...This is on my buddies 400ex, he doesnt know how it happened, he was riding normally, maybe a stick came up and hit it, I dont know. I think everything else is ok. Shifter isnt bent...would anyone know if this is normal steel, or is it hardened, or chromoly, anything I need to worry about. Could i use 70s3?
Reply:.....City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:Safety-silv 45 ( 45% silver content ) and Stay-Silv white flux. Fluxed the joint, wired it together. C-clamped a good hefty piece of aluminum barstock as near to the seal as possible. Braze using O/A as fas as possible, brazing took about 15 seconds. Let air cool. All of the ones I saw were fatigue cracks from poor machining. In all cases the shaft never got hot enough to be un-touchable near the seal. Hot and fast is the key.
Reply:You can use a heat sink clay for around the shaft at the seal. I would recommend it. As for filler, i'd use er70s6, bevel the area and tack it, then build it real slowly with light passes and time to cool off. No wetting it down a bunch, you'll cause more distortion issues than you will solve. For a break like that, a silver solder or braze will be tough to get it to last IMO. You put a big load on those shifters when you land hard and your foot is on it. Not to mention, rock hits will not agree with the stub.It's best replaced, less to worry about, and you won't shear it off 5 miles from the nearest truck accessible trail.......And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:What do you guys think about drilling and tapping it so i could bolt the shifter and/or that nub back on? Honestly my friend is not capable of replacing this shaft, and it isnt worth paying someone to replace it. So I was gonna help him out by welding if possible...
Reply:Pretty much all the points Dave Powelson raised above regarding the material, the seal, and indexing the spline 'cuts' between the two pieces.Also, as stated, that looks like a classic fatigue failure and -not- a one-time event (hit with a rock or stick or stomping on the shifter with a big boot, etc).  Fatigue failure is -not- limited to only hard materials, but because the fatigue failure limit is closer to the yield or ultimate failure levels for non-hard steels you can often get yield or ultimate failure before fatigue more often with those softer and less strong steels.The 'best' fix IMNSHO is to replace the piece.  It is a high stess area, a failure there leaves you most likely stuck or disabled (not counting an emergency ViseGrip repair  ), it has already failed, and the existing splines already look buggered up to some extent already.  A braze repair will probably not hold up any better to fatigue than the base steel did, since the fatigue limit for alloy steels is -usually- much higher than for bronze (a typical brazing filler for use on steel).  As an example, the fatigue limit for 4340 steel can be about 75 ksi (depending on exact heat treatment and such), whereas bronze may be down around 14 ksi.  And no, I don't know if the shaft is/was made of 4340 steel just that 4340 steel is a common and useful steel for things like machine parts.Regarding trying to drill bolt the parts together, IMNSHO, nope.  By the time you drill out enough of the original material in order to have some sort of bolt of a decent size, you don't have much of the original part left!As makoman alluded to, poor machining can also contribute GREATLY to a part failure.  All those little grooves in that machined part are just micro cracks waiting to happen and start the part failure process.  The best laid schemes ... Gang oft agley ...
Reply:Shift shafts are supprisingly cheap and some can be changed without disassembling the engine.  You usually only have to remove the right side crankcase cover and the clutch in order to replace a shift shaft.  I've seen them less than $20 for some bikes.  That's cheaper than  an oz. of most silver brazing alloys.Whatever you do, if you fry the seal, you can just replace it.Last edited by 76GMC1500; 04-20-2010 at 08:24 PM.