air compressor tank repair (no welding)

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I have got an air compressor (25 gallon upright) tank is good, pump is good, the bad, the pipe that goes into the tank is broken off clean. I have tried heat, easy outs, screw extractors, nipple extractors. etc etc. I am at a crossroads with it, I think I want to drill it out and retap it. I have a large welded in bung to work with, it is tapped at 1/4"npt now, I am considering instead of drilling and retapping to 1/4 npt (which might be sketchy as far as sealing) to skip to 3/8 npt and just flush the tank to get the filings out (so they dont gum up the drain valve later)I dont own either a 1/4" tap or 3/8" so part of my reasoning is I wont have to buy the 3/8" later if the 1/4" doesn't work. I have spent enough trying to fix it, I just want it done, am I headed the right direction? fresh metal, fresh start..ideas?Hobart Handler 190 Century 90amp on FluxCraftsman 200amp buzzbox
Reply:I would drill it out as big as a can without geting in to threads and use a punch sharpend like a chisel to pick the parts out. this usely works good on pipe threads.
Reply:I would try one more time by welding a large washer over the broken pipe nipple, then weld a large nut (weld inside the nut to join the washer/nut/nipple combo together)  and as soon as it goes from red hot to dark ..maybe 15 seconds or so use an impact wrench (if you have another compressor or a cordless etc etc available) and it should  come right out. Otherwise a wrench may work fine, but I like the impact for tough jobs. Pipe taps are pricey and hard to get started on a piece thats not in an easy location to keep it square. Try the above first.....I used it to remove 15 broken 18mm (if I recall correctly)  bolts from a front end loader on an import tractor. The guy "saved" a few bucks buying cheap Tractor supply no grade bolts and broke all but one in the tractor when he tried to remove the loader. Total time to remove all of them using that method was about 2 hours if that.Last edited by Coupebuilder; 05-03-2012 at 05:09 PM. "Anybody can talk $h!t behind a monitor, I let the quality of my work speak for itself"Lincoln Square Wave 255 and 355 Tig Lincoln 255 Power-Mig w/ spool gun Koike 5 x 10 CNC plasma Hyd-Mech DM-10 bandsaw Ineco QB-76 NC tube bender
Reply:I don't see any problems retapping to 3/8" if you have enough metal on the fitting.If you do go with the retapping route, be sure to use thread cutting lube, go slowly and back the tap out often to break chips and clean it.  If you thought you had problems removing the broken pipe, try removing a broken tap.Dynasty200DX w/coolmate1MM210MM VintageESAB miniarc161ltsLincoln AC225Victor O/A, Smith AW1ACutmaster 81IR 2475N7.5FPRage3Jancy USA1019" SBAEAD-200LE
Reply:Originally Posted by CoupebuilderI would try one more time by welding a large washer over the broken pipe nipple, then weld a large nut (weld inside the nut to join the washer/nut/nipple combo together)  and as soon as it goes from red hot to dark ..maybe 15 seconds or so use an impact wrench (if you have another compressor or a cordless etc etc available) and it should  come right out. Otherwise a wrench may work fine, but I like the impact for tough jobs. Pipe taps are pricey and hard to get started on a piece thats not in an easy location to keep it square. Try the above first.....I used it to remove 15 broken 18mm (if I recall correctly)  bolts from a front end loader on an import tractor. The guy "saved" a few bucks buying cheap Tractor supply no grade bolts and broke all but one in the tractor when he tried to remove the loader. Total time to remove all of them using that method was about 2 hours if that.
Reply:The heat from the welding usually is enough to brake the bond formed between the nipple and female threads...rapidly expanding and shrinking the nipple is what does it. Unless you are using an actual pipe extractor (they have straight flutes) you may also be creating more resistance by hammering the tapered extractor into the nipple. If the welded washer doesnt work its easy to use a cut off wheel or grinder to remove it and proceed to plan b....I have a lot of plan B's and C's and so on lol. If you must go the cut it into quarters route, maybe an air-body saw blade would work for you...the are narrow on the end and could be trimmed even narrower if needed.Last edited by Coupebuilder; 05-03-2012 at 05:56 PM. "Anybody can talk $h!t behind a monitor, I let the quality of my work speak for itself"Lincoln Square Wave 255 and 355 Tig Lincoln 255 Power-Mig w/ spool gun Koike 5 x 10 CNC plasma Hyd-Mech DM-10 bandsaw Ineco QB-76 NC tube bender
Reply:Milwaukee did make a metal sawzall blade that will fit..  Get the smallest cold chisel  or cape chisel you can find. Place chisel between nipple and the fitting. hit with hammer until it collaspes enough  to grab with needle nose pliers.
Reply:I had the same problem with my compressor.  It took time and patience but I worked it out with an Ez-out and a cape chisel.  When I put the nipple back I used a brass nipple and I coated the treads with Anti-Seize. When It broke again it came right out.
Reply:Die grinder or dremel grind down the broken nipple usually you see the threads than heat remains of the nipple they will heat fast cause they are thin than pick outwith a pick or screw driver. I have also used a tap with a lot of oil to clean the chips after the die grinderMillermatic 252millermatic 175miller 300 Thunderboltlincoln ranger 250smith torcheslots of bfh'sIf it dont fit get a bigger hammer
Reply:Is it absolutly clean on the break or is there some metal sticking out like a 1/8"?If I had any sticking out I would take a piece of square rod and drive it into the pipe ( hard with a big hammer ), then I would weld the pipe to the square rod, just a couple inside tacks but solid. Then use a cresent wrench and some " gentle heat " to get it out.Do not weld on the pipe flange on the tank just the inside of the pipe. When done run a tap, down the fitting, and use thread sealer, not teflon to seal the new pipe.!!!! OR die grinder it flush, drill out the old pipe, to under 3/8 ( check your tap chart ), retap with 3/8.
Reply:If you don't have a Dremel tool or a saw blade which will fit, you can use a thin metal file -- probably a round one is best -- on opposite sides of the hole and once your grooves get near the threads of the tank, you can slip a flat 'blade' or piece of metal into the grooves and use a wrench to try turning the fitting. First hitting the pieces with a chisel or heating the remaining sections, even with just a small propane torch first, does usually help break them free from the tank. Another trick that sometimes works well when parts are hard to hold, as with threaded thin tubing, is to epoxy something inside to grab onto. Lots of surface area means lots of torque can be applied, even using such a bond of 'lesser' strength.
Reply:Originally Posted by Oldiron2If you don't have a Dremel tool or a saw blade which will fit, you can use a thin metal file -- probably a round one is best -- on opposite sides of the hole and once your grooves get near the threads of the tank, you can slip a flat 'blade' or piece of metal into the grooves and use a wrench to try turning the fitting. First hitting the pieces with a chisel or heating the remaining sections, even with just a small propane torch first, does usually help break them free from the tank. Another trick that sometimes works well when parts are hard to hold, as with threaded thin tubing, is to epoxy something inside to grab onto. Lots of surface area means lots of torque can be applied, even using such a bond of 'lesser' strength.
Reply:at the point your at, I would drill and tap, and if you have the metal I would most likely jsut go to the 3/8" tap,  if not I have drilled out pipe and then retapped with the same size, and no problems, but at times one can be off a little and not center up and have kinda mess that may not seal up properly,
Reply:thanks for the advise all, there are TONS of good ideas. thanks for the input, not sure which I am going yet, as of this aftrnoon I seem to have gotten the flu thats going around, lots of fun there. I will see what I can come up with in terms of tools that will work (and can afford lol) but will likely be monday or tuesday before I bother with it unless theres a miracle tommorow. have a great night all thanks for the advise.Hobart Handler 190 Century 90amp on FluxCraftsman 200amp buzzbox
Reply:If there is a small amout of metal sticking out where you can get to it then take a small cold chisel or center punch and drive the edge towards the center and move around to the other side and do the same until you can take a pair of pliers and remove the broken piece from the hole
Reply:FYI, the carbon steel taps are fairly cheap.  Last I bought was a irwin 1/4" npt and I think it was $7.xx.  This was a 'need it today' purchase from the local hardware store.  You might find cheaper if you shop around.  The high speed steel ones are about 3x the price, but seem to be worth it.  Last I bought was a Hertel 3/8" npt from enco for $24.80.   The carbon steel ones seem like they break a whole lot easier.Dynasty200DX w/coolmate1MM210MM VintageESAB miniarc161ltsLincoln AC225Victor O/A, Smith AW1ACutmaster 81IR 2475N7.5FPRage3Jancy USA1019" SBAEAD-200LE
Reply:I got to feeling well enough to fool with it, I decided to drill it and tap it to 3/8" all went smoothly. while I was fooling with it I installed a lazy mans drain valve (the kind designed for tractor trailers, pull cord) I am including pics of the finished repair.I changed my routing layout a bit so my regulator is more out of the way so I wont have this mistake again. either way, its working well, thanks for the advice and help. Attached ImagesHobart Handler 190 Century 90amp on FluxCraftsman 200amp buzzbox
Reply:Interesting thread.  Over the years, I've gone through my share of broken threads, extractors and bolts. A couple of years ago, I had a few threads break off inside a female elbow which was located inside a shower wall which I most definitely did not want to break into. The problem with most extractors is they exert pressure from the inside out .... making the problem worse. I took an old 7/8" spade bit, cut the point off and ground the sides down to a gentle taper, maintaining a shallow cutting edge until I could insert it, then hammer it into the broken threads. This will actually cut two slight grooves down the inside of the broken pipe thread without distorting, or worse, expanding the nipple. If you get a firm enough fit, you can crank the threads out with a crescent wrench and not have to tap anything. Attached Images
Reply:in my google searches I saw the same kind of trick with a chisel, never considered using a drill bit, which of course would allow me to use the appropriate size.. thanks and maybe it will help the next person!Hobart Handler 190 Century 90amp on FluxCraftsman 200amp buzzbox