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  • Draw bender

    So...…...like...…….I'm in the middle of a truck repair, hydraulic cylinder repair, and other stuff.

    Truck progressed to the point that it's gonna need some tubing bent. EGR tubing.

    There's 2 kinds of bending, when it comes to tubing...……...compression bending, and draw bending. Compression bending is pretty simple...…..just run a roller around a die, and crush the tubing to conform to the die. Draw bending pulls the tubing through either a set of rollers, or a roller, and a die.

    We're doin' a draw bender here at the compound.

    Cut some plate
    Once the plate is cut, machined, and beveled...…...it's time to turn an assembly/alignment fixture.

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    The purpose of the turned round stock is to hold the components in line while welding. This assures that everything is square.

    Initial fitup to check the machining, and whether it's all gonna turn out square.

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    This is a critical step. We're building to thousands on this one. A shaft will go thru this hole,, and it has to be dead nutz on.
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    Last edited by farmersamm; 02-12-2020, 09:48 AM. Reason: some pics didn't upload properly

  • #2
    The weld out is a PITA. Forgot to take pics of all the stinkin' clamps that were required to hold it all together to keep everything aligned.

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    I like 7018,,,,,,,,,,,,****,, it's about all I run I guess. Good stuff for heavier plate.

    Anyways...……...she's ready for additional milling...…..

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    One end is solid welded, while the other end only has a spacer to hold dimensions....this'll become apparent later.

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    As usual, I had a U-Turn about midway thru the process. Stored internal stress.

    Slotting the material, prior to welding, caused the stress to move the metal. Shoulda remembered that metal has a ton of stress in it when it comes from the mill...…..especially A-36. She moved on me...……

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    .010 might seem like an inconsequential amount, but.........it's unacceptable. Made a new top plate, and moved on. LIfe's lessons.

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    • #3
      DOM is turned to fit the hole. Although the hole started out at 1.375 , it wound up at 1.374, and 1.376, in another direction...…...welding distortion is a powerful thing. Anyways...….the DOM is welded in with less-than-full-length welds. Don't need a ton of weld, just enough to hold it all together. Two half circle welds will do the trick, while keeping heat input to a minimum.

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      The assembly is then clamped to the table, and slotted.

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      I've recently switched to mostly carbide milling cutters. Resisted it for years, but finally pulled the trigger.

      They're very good for dry milling. Wear like iron. I'm getting tired of running flood coolant, and making a Holy Mess..........and I'm seeing dilution of way oil, leading to some wear. There is a tradeoff though. The carbide cutters aren't as sharp, and tend to bulldoze the material, instead of shearing it. Nothing I can't live with. You can see, in the above pic, the wraparound on the cutter. A HSS tool would have cut the material where it exits the cut path...….carbide tends to just let it flop until it's sucked back under the cutter, and sheared.

      Carbide on a small,, underpowered mill,, is the same as using carbide on a small lathe...…………….Carbide needs high speeds, and aggressive feeds. Otherwise, it cuts less than optimal. But...……..like I say...…..wears like iron, and eliminates the coolant mess.

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      Once the slot was cut, the deck was checked for movement. Slotting removes material that otherwise would resist welding distortion. I'd imagine the deck is out by about .005 . This could be remedied by decking the assembly with a face mill, but it ain't the Space Shuttle, so not worth the effort. At least, that's what I'm sayin' now Probably drive me nuts, and I'll get out the face mill, and give it a once over

      Comment


      • #4
        Finally...……….the excess DOM is milled down.


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        Probably get a start on the bending shoe today, if the weather permits.

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        • #5
          Excellent pics and good construction detail for those not as blessed with so many tools! And, the skills to use them!
          Last edited by Northweldor; 02-12-2020, 06:04 PM.

          Comment


          • #6
            I have missed Sam's projects!

            Comment


            • #7
              Thanks y'all………….I tend to do things the long way around, and piss a lot of folks off, but anyways.....thanks. It's always a long journey.

              The point of this whole thing, which has stretched out over a month, is making a new EGR tube. The original is made out of Unobtanium...…...so called OEM replacement tubes are too short, and are solid tubing, with no provision for flex. And, this is a truck with a forever home, we can't afford a new one.

              The original tube is...…………….

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              I got some stuff in today...…...little brown truck paid a visit.

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ID:	707895 I couldn't find a source for any kind of stainless flex tubing. Up to now, I planned on using copper ACR soft tubing, not really a good choice. It finally hit me...…….I'd seen some flex tubing on water heaters that weren't copper. BINGO!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! This stuff is 3/4 ID, and the original hard tube is 5/8 OD. Little silver solder to mate the two types of tubing, and I'm in business. (All the fittings, and connections,, from the factory, were silver soldered...…….which is why they self destructed when the parts were taken off the truck)

              Also got some SS tubing in. 5/8 OD, like original...……. .020 wall thickness. GROOVY! (They still say that????????)

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ID:	707896She puts up with this crap. I love her for it. But, here's the rub...……..the tubing is welded tubing, not seamless. It's bendable, but it can't be double flared, as far as I know. So, parts of the old tubing assembly have to be salvaged...……...the end that fits the EGR valve is a double flare connection. So...…..we gots a ton of silver soldering to do.

              This is completely insane. All this work for a little tube. Thing is...…...it's cheaper than a new truck payment, and I've sorta wanted a small diameter tubing bender, and so here we are ROFL. The bender is gonna come in real handy...…...hyd lines on the loader, baler, swather, tractors, etc. I can now quit replacing failed hard lines with hydraulic hose, which is a lousy replacement option. I'm not doing all this to prove that I'm "cool"...….it's just the way I've always done things...…….to which K'kins sometimes throws up her hands in frustration.
              Attached Files

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              • #8
                Two blanks had been cut out of some drops I picked up at the LWS. I buy scrap, and drops, off their plasma station.
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                Click image for larger version  Name:	exhaust flange686.JPG Views:	0 Size:	221.6 KB ID:	707921Not knowing where I was going with this at the time I cut the blanks, I cut them oversize. At this point they can be pared back to something close to what's gonna go on the lathe. I find it easier to cut in segments when I cut round stuff. I don't weld round stuff real good, and the same goes for cutting.
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                Small manageable sections of the arc, just sorta whittle it away.

                Next, the blanks are ground to the pencil line. I like to grind close to the line on top, and let the grinder tilt so that the bottom slightly flares out. This keeps ya from going into material that you need...….undercutting your line.
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                Click image for larger version  Name:	exhaust flange689.JPG Views:	0 Size:	193.7 KB ID:	707924You can see how the grinder was tilted.

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                • #9
                  The reason for using two discs is to utilize thinner plate to make thick sections. I laminate a lot of stuff to make it thicker...…...cheaper to do.

                  Laminating requires more labor though...……..First step is drilling a hole for a press fit pin. I like to use a wiggler to find my center punch dimple. Works within a few thousands if you're careful.
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                  Anyways...….the hole is made. Usually I use a spotting drill for starting a hole, but this time around I used a center drill. Was ok, but there was a bit of chatter as the bit entered the pilot hole. A spotting drill is a full diameter starting point, and prevents the flutes from chattering as they start the hole.
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                  Holes are then checked for square. Always check stuff...……...it beats having to come back and redo it when, down the line, you might run into alignment issues.
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ID:	707929The reason for checking, is that these holes have to line up perfectly...…...they're gonna have a press fit pin in them to hold the two discs tightly aligned for the next step in the process. HSS tool blanks work nice for this.........this is a boring bar that I ground for the boring head, now it's a gauge

                  Comment


                  • #10
                    Drilling is anything but precise. I'm looking at a difference in runout between the two holes. Would have been a bit cleaner if I'd used a spotting drill, but it's manageable.
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                    Runout was .008 in one hole, and .010 in the second hole. This has to be tended to...……..bores have to be identical to fit the pin. On a relatively tight press fit, we're looking at about .002 interference to hold the discs together for further machining, and welding.

                    Comment


                    • #11
                      Finagled the holes, or so I thought (turns out one was a tad off after finoogying), cut a pin to size, and pressed 'er in. Halfway through, the pin hung up, and I had to mushroom the head to get it in

                      Anyways...……….the new connector pin holes are drilled.

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                      And 3/8 stock is turned to fit the holes. The holes were drilled .368, and with runout, wound up being .370 . Was a total PITA to turn the skinny 3/8 cold roll to size. Lot of deflection...…….and cold roll turns lousy anyhow.

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ID:	707949You can see how much runout was in the stock + runout in the 3 jaw. The chips are short...…..showing that the metal is cutting more on one side than the other as it rotates. PITA. I really hate working with thin round stock.

                      But, the pins fit, so I guess it's just part of the game.

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                      • #12
                        The pins are seated flush on the hydraulic press.

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                        Then countersunk on the arbor press (more feel for what yer doin').

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                        The assembly is now ready for plug welding.

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                        • #13
                          Wow. I'm impressed.

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                          • #14
                            Yeah, well, don't be too dam impressed...……...some days go better than others

                            The discs are plug welded...…….so far so good.

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                            Then the center is cut out for a shaft. The too-tight press fit caused some issues, but I was able to cheat my way out of it. The hole wasn't totally perfect, so a turned center was used to center the blank for cutting.

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                            The hole was about 95% undamaged, so it couldn't be indicated properly...………...but I keep a turned centering tool on hand. Do these in a 4 jaw chuck, and they can be pretty accurate...…….you're turning the point, then taking the piece out of the chuck, and turning the shank that fits in the milling machine. The 4 jaw can keep your tolerances to about .001 . Set your clamps sorta loose, lower the point into the hole, and it will drag the piece to center...……..then you can tighten your clamps.

                            Blast the center out with an annular cutter, and she's ready for the next step.

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ID:	707992Kinda looks like noodles

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                            • #15
                              Time to work on the shaft. This is where the day went South

                              I was able to keep my dimensions...……..BUT MY SURFACE FINISH JUST PLAIN SUCKED!!!!!!!!!!!!

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ID:	707994This one was sorta ok. The tool was still sharp.

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ID:	707995This was the beginning of a crap day. I didnt' realize that the bit was at the point of getting dull...…………….made one good pass, then started tearing the material, instead of shearing it. Is what it is...……...and I ain't broadcasting the disaster to the world This end of the shaft only required about .008 turning...……...too late to sharpen the tool once you're into the cut.

                              Pulled up my undies Click image for larger version

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ID:	707996, and threaded the end of the part...………...AT LEAST THIS WASN'T TOO UGLY. 1018 is a beetch to machine unless you got a good shear tool...……...same with threading.....the tool has to be razor sharp...….and then it isn't a piece of cake. 1018 is just some nasty stuff

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