Trying to Rescue a Tool, Welds Breaking?

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I'm trying to rescue this Rotozip Zipsaw that I bought only last year.  The bolt which secures the blade is stuck... really stuck.  I broke two allen wrenches trying to remove it.  It isn't cross-threaded, but neither does it want to loosen.  ( Rotozip has no comment, apparently they have my money, and that's good enough for them. )   So I tried to weld a handle onto the bolt head, using a 7" long scrap piece of 1/2" bar.   Two attempts, and both times the bead broke in the middle, as you can see.  I don't understand why.  I clamped the body of the saw to the table, and tried to loosen the bolt, but only succeeded in ripping the bar off with my bare hand.  I don't think I'm __that__ strong.  Even a little tack should be stronger than that.   1/16th ceriated, 150 amps DC, 1/16th 70S6.   Any suggestions?  Thanks.__David Hillman
Reply:go buy another one use it for a few weeks then take the broken one back lol make sure u buy it at walmart every little bit u can stick it to them makes me happy lolI forgot how to change this.
Reply:Are you sure it isn't left handed thread?
Reply:Originally Posted by LawsonWeldingLLCgo buy another one use it for a few weeks then take the broken one back lol make sure u buy it at walmart every little bit u can stick it to them makes me happy lol
Reply:Clearly in using that attack on it you have greatly restricted the already small area you have to weld to...   Thus your handle can put out more torque than your weld can take... Are you sure you are turning the bolt the right direction ( right hand thread, left hand threads ?)Most of the fixes on things like this I have seen involved using ' high allow' rod and welding as much of the top area as possible ...either stacking it and then grinding sides for a wrench to fit... OR the more common method of using the same high strength rod and ' plug ' welding a good NUT onto the top.... this keeps the forces confined to a very small distance and gives the most weld area both...Weldandpower Lincoln 225 AC,DC with Briggs 16hp gas engine.WW2 era Miller TIG.
Reply:Originally Posted by jontheturboguyAre you sure it isn't left handed thread?
Reply:FKE is a  high tensile cap head bolt 70S-6 has excellent welding results on mild steels where poor fit-up, rust and oils may be present.Do you have any ER70S-2 to try? Higher strength.Did you try heating the bolt when you used the allen?Just trying to come up with some ideas for yaSemper FiJesus may have been a Carpenter, but his dad was a Millwright" A grinder and a can of paint, will make a welder what he aint' "I've done so much, with so little, for so long, that now I can do anything with nothing!
Reply:Originally Posted by jontheturboguyAre you sure it isn't left handed thread?
Reply:I've found stainless to be the best thing to use when welding to alloy bolts. Any other method I've tried either leaves to brittle a weld or breaks off the bolt to easily.Millermatic 252XMT 304'sDynasty 280DXHypertherm PowerMax 1250Miller Trailblazer 302 EFIOptima PulserXR feeder and XR Edge gun and more athttp://members.dslextreme.com/users/waynecook/index.htm
Reply:Originally Posted by skelley521FKE is a  high tensile cap head bolt 70S-6 has excellent welding results on mild steels where poor fit-up, rust and oils may be present.Do you have any ER70S-2 to try? Higher strength.Did you try heating the bolt when you used the allen?Just trying to come up with some ideas for ya
Reply:Originally Posted by skelley521Do you have any ER70S-2 to try? Higher strength.
Reply:Originally Posted by irish fixitI've found stainless to be the best thing to use when welding to alloy bolts. Any other method I've tried either leaves to brittle a weld or breaks off the bolt to easily.
Reply:Originally Posted by sn0border88Both have 70KSI tensile? I would also recommend using a stainless filler wire, should help make the weld less brittle.
Reply:Originally Posted by David HillmanI have some 308 and 309, does it matter which?
Reply:David , Did you SEE my post ?   I addressed the basic problem.... not enough surface area and size of bead available... and this is not new info...as other bolt removal threads are in the archives talking about the NUT solution....   But you seem to be concentrating on going higher tech....?Weldandpower Lincoln 225 AC,DC with Briggs 16hp gas engine.WW2 era Miller TIG.
Reply:grind the head of the bolt off. If it is truly not cross threaded it will thread right out with your fingers.
Reply:Originally Posted by GBMDavid , Did you SEE my post ?   I addressed the basic problem.... not enough surface area and size of bead available... and this is not new info...as other bolt removal threads are in the archives talking about the NUT solution....   But you seem to be concentrating on going higher tech....?
Reply:Hat tips to Irish Fixit and Sn0border88.  Ground off the old weld on each side, and did it again with some 309.   That did it.  Had to be at least 100 times stronger with stainless filler.   I had to put a 3' breaker bar on it, but the weld held just fine this time.   WeldingWeb wins another one    Thanks.__David Hillman
Reply:Anti-seize on next bolt perhaps?
Reply:It sounds like you have made this into " your welding ability " instead of "how to get the bolt out"...  which is ok if you recognize that at some point.....the people replying are serious  welders..... I am an old mechanic... who has used welding to do things with machines.... so my orientation is different.I estimate that choosing the best nut would give you 7 times the welding contact area....and a larger weld mass also.... I do not even know what I used in the past to do this procedure with.... I went to ACE hardware and got ' high alloy' in a small size rod which was less than half the size of the hole I needed to plug weld into... it has always worked first time.  and I am not that good a welder. I may have 5 hours actual welding time since 1972... I find  that farm welding is actually mostly  ' grinding' .....I still have remnants of the 50 lb box of 6011 I bought in 1972... LOLWeldandpower Lincoln 225 AC,DC with Briggs 16hp gas engine.WW2 era Miller TIG.
Reply:Stuff like this where you don't have a lot of room to weld a nut on I like to weld a flat washer on through the center then weld the nut to the washer, seems to work pretty good."Si Vis Pacem Para Bellum"Lincoln Idealarc 250 AC/DCMillermatic 251   Syncrowave 300   30A spoolgunLincoln MP210Hypertherm 45(2) LN 25(2) Lincoln Weldanpower 225 CV(4) SA200   1 short hood    SA250    SAM 400
Reply:Actually on a job like this my favorite method is to take a piece of flat bar say 3/16x1 to 1/4x1 1/2" in size. Drill a hole near one end the right size and weld it. Works great if you've got the room for a bar to spin.Millermatic 252XMT 304'sDynasty 280DXHypertherm PowerMax 1250Miller Trailblazer 302 EFIOptima PulserXR feeder and XR Edge gun and more athttp://members.dslextreme.com/users/waynecook/index.htm
Reply:Kolot and Irish Fixit...   Both of those are excellent suggestions....Weldandpower Lincoln 225 AC,DC with Briggs 16hp gas engine.WW2 era Miller TIG.
Reply:I was in the "Grind the head off" booth myself. At least you got it off, and I learned something today. It's a win-win day."The beauty of the Second Amendment is that it will not be needed until they try to take it." - Thomas Jefferson If the Lights are a Flashin', STAY OFF the tracks!!! It might be me at the Throttle...
Reply:Maverik, this is not a one solution is best situation.... lots of factors go into it... this tool needing help is portable... under a car with a messed up bolt , a tap broken off, no room to get a grinder to the object,  could  make a big difference..  This is also not something where if the method failed it would be a huge cost....If this were some old lathe being restored....and you had a situation where if you grind it you have no BACK UP plan... as where it breaks off lower into the holder.. .or if the threads are the cause of the problem... like corroded in place...or partly stripped due to someone else cranking on it the wrong direction...or a set screw being left in place when a puller was applied to it... then grinding off the head may leave you with a worse situation.. nothing to hold on to or build up to work with.....Weldandpower Lincoln 225 AC,DC with Briggs 16hp gas engine.WW2 era Miller TIG.100 ways to skin a cat.I would have tried a impact or heat. Where did you ground to and how does it run?We once smoked a grinder laying on the weld table. The table was grounded, but I guess the grinder and the electric cord were the path of least resistance.The smoke rolled....lol.Semper FiJesus may have been a Carpenter, but his dad was a Millwright" A grinder and a can of paint, will make a welder what he aint' "I've done so much, with so little, for so long, that now I can do anything with nothing!
Reply:The other end of the 1/2" bar was held in my ground clamp.  Unit was unplugged, as well.  Motor on the unit seems to be fine, but I don't have a replacement bolt on-hand (not sure of the thread, either), so I can't test it under load.__David Hillman
Reply:Nice and Congrats on the removal Save the lock bolt so you can compare the threads.Semper FiJesus may have been a Carpenter, but his dad was a Millwright" A grinder and a can of paint, will make a welder what he aint' "I've done so much, with so little, for so long, that now I can do anything with nothing!
Reply:My rotozip bit the dust also.. can't get no damn replacement parts.. it's now a garage ornament, I use my 4-1/2" grinder to cut stuff..www.thefusionsolution.com