Issues welding threaded inserts into tubing

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Ok normally I do not run into problems doing these, but I have a fairly thick wall tube with a thin insert, 2"x.250 wall tubing and the thread in insert accepts a 1.25" rod end so that gives me less than .125" wall thickness of pure material.. Now that I plot it out and realize how thing the insert are I had my machine running about 160 amps.. I made two passes on the OD and once it was all done the threads looked fine, but I couldn't get the rod end into the insert now. Made it about 7-8 thread and got stuck, on both sides... Then I get the bright idea of trying to heat the insert back up and letting it cool, well I didnt follow through with the letting it cool part and then the rod end got seized in the insert...  That looks like an 80$ mistake... Maybe I need to weld these in a positioner so I can get it done quicker and lessen the heat input.. I cannot tap them because where am I going to find a 1.25" tap left and right hand thread... I was thinking about trying to put them in the lathe, pick up on the thread and single point it to clean it up but it sure seems like a lot of work.. Any ideas? I would love to get my rod end out of the tubing as well... I guess I could cut it out if I have too...HTP Invertig 201Lincoln Idealarc SP250Miller 180 AC StickBy farmall:They should have held the seagull closer to the work, squeezing evenly for best deposition.
Reply:I am not sure of your description but a single pass around a threaded nut will shrink the nutb so much that it is impossible to use the thread.  Even if you were to tack weld a nut onto a surface you cannot weld all around.  A tack on two or three flats is about all that can be done before the nut is unusable.
Reply:I know some of the race car fabrication shops used to sell taps and dies for the rod ends.  Next time.As you figured out, heat shrink will lock things in like you wouldn't believe, but heat will also loosen them again.  Somewhere around dull glowing red, you are going to get into trouble with the heat treat on the rod ends.  If you can heat the tubing and bung enough while turning the rod end, it should come out.  I'm not sure how you will inspect that rod end.  It maybe dead.If you haven't ruin the rod end yet, I would try moderate amounts of heat and and rig up a breaker bar.Oh, and for a tap:http://www.mcmaster.com/#left-hand-t...d-taps/=g19lh9Usually arrive in 2 days.... Check the prices.... Ouch!Con Fuse!Miller Dynasty 350Millermatic 350P-Spoolmatic 30AMiller Multimatic 200Hypertherm PowerMax 1000G3Miller Maxstar 200DX
Reply:Originally Posted by lotechmanI am not sure of your description but a single pass around a threaded nut will shrink the nutb so much that it is impossible to use the thread.  Even if you were to tack weld a nut onto a surface you cannot weld all around.  A tack on two or three flats is about all that can be done before the nut is unusable.
Reply:I would try to get that rod end out like this: Get a helper. Hold the rod end in the vise with the tube pointing up. Heat the tube/insert while having your helper cool the rod end with a squirt bottle or wet rag (be careful of steam burns). Hopefully the tube will expand while the rod end stays cool and you can get em apart. When I used to make tie rods with tube inserts, I always chased the threads with the appropriate tap after welding. If the tube and insert are 4130 you will need to anneal before chasing the threads.Ian TannerKawasaki KX450 and many other fine tools
Reply:It is a 100$ tap for each thread though.. Maybe it was just how I did it.. Maybe I will rig up a positioner so I can weld it all the way around quicker, I did weld these pretty slow... I dont think I will ever mess around with a 1.25x12tpi thread so I am having a hard time buying a tap for it...HTP Invertig 201Lincoln Idealarc SP250Miller 180 AC StickBy farmall:They should have held the seagull closer to the work, squeezing evenly for best deposition.
Reply:No need to buy a $100 tap.You aren't cutting new threads, you're chasing existing ones. Buy a 1.25-12TPI bolt and score it with a small cut off wheel in at least two spots equidistantly around the diameter...sometimes I'll do three grooves.Use anti seize or a cutting/tapping fluid and run the bolt into the bung just like a tap but make sure it's AFTER it has cooled completely. Clean the threads well and all should be good.It'll cost you about $10. Attached Images
Reply:Originally Posted by sn0border88This statement couldn't be more of an outright lie if you tried.  I couldn't count how many threaded bungs/nuts/standoffs I've welded 100% to plate/pipe/ect.  Sounds like you just overheated it, or welding in opposing directions.  Usually if welding something like that on you want to keep your bead moving in the same direction, spreads the heat out and prevents the nut/bung from cooling out-of-round.Positioners are great for this type of work, but not needed.  Just keep an eye on your heat and weld in the same direction.  Its a good idea to use anti-seize when you thread the parts together for the first time as well.
Reply:Sorry that I lied.  I really want to apologize.
Reply:Whenever I weld bungs of that size/thread combo on I buy a bolt of the correct size and coat it generously with anti-seize and thread it fully into the bung when welding. As the joint cools thread the bolt in and out a few times and leave it in until the joint has cooled completely. Should come right out and you don't have to worry about melting parts of the rod end.
Reply:Originally Posted by ZTFabNo need to buy a $100 tap.You aren't cutting new threads, you're chasing existing ones. Buy a 1.25-12TPI bolt and score it with a small cut off wheel in at least two spots equidistantly around the diameter...sometimes I'll do three grooves.Use anti seize or a cutting/tapping fluid and run the bolt into the bung just like a tap but make sure it's AFTER it has cooled completely. Clean the threads well and all should be good.It'll cost you about $10.
Reply:I'm lucky I have any size tap in rights and lefts but done properly there should be no issue......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:I see your threads are 1.25" x 12 tpi, was gonna offer you the taps as a favor but mine are 6 tpi, have a matching set of LF, RH from an auction a while back. Have not used then yet.
Reply:If the threads are induction hardened they will start to loose strength and hardness when the temps get over 400F. Grade 8 similar but not as fast.Hopefully you don't have too many threads in an interferance fit and may be able to shape the threads around the shaft some.I'd first prolly get a lead or copper beater out and roll the tube while striking the outside and see if it will give a little. If it moves hand turn until it stops and repeat the beating thing etc. etc.You can also wick some lube down by warming the tube and drawing light oil from the shaft to the heat. Don't get carried away with the heat as oil begins to break down over 250-300F.Good LuckMattPS, I like ZTFabs thread chaser solution, I have the right hand but not the left (at least I don't think so anyway).
Reply:Paul, I've done the old thread chaser bolt trick many times, but never cut the slot at an angle like you show. I just made it straight with the length of the bolt, perpendicular to the threads. Usually three slots 120 degrees apart. What is the advantage to angling the slot?
Reply:Originally Posted by daddyPaul, I've done the old thread chaser bolt trick many times, but never cut the slot at an angle like you show. I just made it straight with the length of the bolt, perpendicular to the threads. Usually three slots 120 degrees apart. What is the advantage to angling the slot?
Reply:Thanks. I'll try that next time.
Reply:Originally Posted by DSWNeat trick there Paul. I'll have to remember that one for the next time I need to clean up an odd ball thread. And of course as usual your beads are excellent.
Reply:Neat trick! It looks like you weld yours in a positioner right? I am sure that would help me too, keep the heat moving along.. Well I shall mess with it tonight, see what I can do...HTP Invertig 201Lincoln Idealarc SP250Miller 180 AC StickBy farmall:They should have held the seagull closer to the work, squeezing evenly for best deposition.
Reply:Well looks like I donated that rod end to the metals gods.. Its stuck in there... Guess I will have to cut the bung out, weld a new one in and get a new rod end.. BlehHTP Invertig 201Lincoln Idealarc SP250Miller 180 AC StickBy farmall:They should have held the seagull closer to the work, squeezing evenly for best deposition.
Reply:Originally Posted by ZTFabNo need to buy a $100 tap.You aren't cutting new threads, you're chasing existing ones. Buy a 1.25-12TPI bolt and score it with a small cut off wheel in at least two spots equidistantly around the diameter...sometimes I'll do three grooves.Use anti seize or a cutting/tapping fluid and run the bolt into the bung just like a tap but make sure it's AFTER it has cooled completely. Clean the threads well and all should be good.It'll cost you about $10.
Reply:Originally Posted by fordmanNeat trick! It looks like you weld yours in a positioner right? I am sure that would help me too, keep the heat moving along.. Well I shall mess with it tonight, see what I can do...
Reply:Originally Posted by Drf255Wholly crap batman.  Those beads look machine made.  Novice here, but is there any reason he can't thread a bolt into the end before welding and remove afterwards?
Reply:Originally Posted by ZTFab
Reply:A few years ago Frank Ford posted some photos of his homemade 19mm tap. I really liked the technique and in a pinch or where a budget was a concern... maybe this would work.http://www.frets.com/HomeShopTech/Pr...p/19mmtap.htmlmost of the advise given has been good, however there is a high temp antiseeze that will work even better, we were have a lot of problem with volvo diesel engines and had to do warranty work on them.  The specs called out for a high temp antiseeze that contains brase in in and cost a lot more but is worth it in the long run might want to give that a try as well.  just my dumb aazzz sugestion.