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  1. #1
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    Alignment checks along the way (TIG)

    I would like some input into alignment checks that occur along the way.

    What kind of things do you check and in what order to you join the tubes and make the checks?

    For my current build, the first step is the seat tube to BB joint. For this joint my tacking was short welds in the front and back. This is my third build and I am still trying to refine my process as I grow to understand the impact of weld sequence.

    After short tacking welds fore/aft I was 6mm out of alignment when measured at the end of the seat tube. The lean was towards the drive side.

    My weld along the non-drive side "pulled" the tube to be about 1mm off (it was off in the same direction). I did a second pass on the non-drive side to bring the seat tube to be 1mm off this time leaning away from the drive side.

    When welding the drive side I tried to go fast and after this was complete, the lean was 0.3mm towards the drive side.

    Is a 0.3mm alignment at this point in the process typical? I figure some things will change when I put the seat stays and chain stays in place, hopefully keeping an eye on this along the way will allow this bike to be built true.

    For my next step, is it better to attach the seat stays first or should I attach the chain stays prior to putting the seat stays on? The other option is to do the down tube/BB joint as the next step, so many options.
    Last edited by febikes; 05-24-2011 at 04:59 AM.

  2. #2
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    Quote Originally Posted by febikes
    first step is the seat tube to BB shell joint.
    FYP. Tired, huh? I'll email you the pictures of the joint.



    Jon

  3. #3
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    Here's what I do

    Everyone goes about it differently. For what it's worth, 0.3mm out (on anything) is more than good enough. Also, running multiple passes to align things is not the way I would go about it - try to minimize how much you're heating up the joint. It sounds like your mitering is not very good if your tacked seat tube is 6mm out. Remember that the miters are the main driver of good alignment, not weld sequence.

    So that said, here's what I do:

    Step 1: Tack seat tube to BB shell, do a quick check to see if something is way off. If it is, pull the joint apart and re-check the miter. If not, go to step 2.

    Step 2: Finish weld seat tube to BB shell, check alignment. Cold set (ie, pull on until it bends a little) if needed to get alignment spot on.

    Step 3: Tack downtube to BB shell and head tube. Check alignment, and if something is way off, pull back apart and fix the miter. Otherwise, on to step 4.

    Step 4: Tack toptube to seat tube and head tube. One more alignment check, and once again, if something is wrong, pull apart. Otherwise, I weld up the front triangle.

    Step 5: Check the fully welded front triangle. If there are any alignment problems, I will correct with minor cold setting. If there are serious alignment problems (this has never happened to me when using the steps outlined above) I would probably throw away the front end and start over.

    EDIT: Read Don's post. Doing what I'm doing here won't hurt you, but it is probably a waste of time. I've been chasing my tail here due to BB shell distortion.

    Step 6: Tack chainstays to front triangle, check alignment (ie, are the dropouts in phase with each other, are the stays in plane with the rest of the frame, is there any twist in either direction) and correct if needed. Finish weld chainstays, FACE BB SHELL and check again.

    Step 7: Tack seatstays to dropouts/seat tube, check alignment again, same story.

    Step 8: Finish weld the rear end, one more alignment check (at this point, if you have any problem with the rear end, you'll either have to cut out a stay and replace it, or file/modify a dropout to fix it, most likely - most problems at this point can't be fixed any other way).

    Step 9: Add all the little stuff. Generally bridges and brazeons won't do anything to your alignment unless you really do something weird, but I do a final check after everything is on anyway.

    That is a lot of checks, I know, but if you don't start checking things early, a small problem can mushroom into a much bigger (usually unfixable) one.

    -Walt
    Last edited by Walt; 05-25-2011 at 08:57 AM.

  4. #4
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    /\ Great explanation of your process! I don't think I've ever read anybody explain their process to this detail.
    May the air be filled with tires!

  5. #5
    DWF
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    I've posted this elsewhere, don't know that I have here, but this is what I recommend. New builders are going to have trouble with this just from a lack of confidence/experience perspective, but imo, this is the most efficient/easiest/fastest way of getting from raw tubeset to finished product:

    **********
    There is only one proper way to build the frame, IMHO, and that’s to follow these steps:

    1. Set fixture up to design specs, i.e., seat & head tube angles, head tube height, chainstay angle/BB drop, and the appropriate BB spacer/setting.

    2. Start with a blueprinted shell (one you know has true & parallel faces) installed on the BB tower.

    3. Install your seat tube parallel to the fixture; tack it or weld its full circumference in the fixture if TIG welding. Do not remove the seat tube from the fixture at this point.

    4. Install blueprinted head tube in the fixture.

    5. Miter, prep, and check top tube fit in fixture.

    6. Miter, prep, and check down tube fit in the fixture.

    7. If the DT & TT fitment are correct, tack them in place. If TIG welding, weld however much you feel comfortable with. Rotate the fixture to allow you to weld as much of the BB shell and DT joint as you can following a proper weld sequence. Do not remove the frame from the fixture at this time.

    8. Miter, prep, and check chainstay fit on BB shell in fixture.

    9. If chainstays are correct, tack them in place. Install any bridging if you have not already done so. If TIG welding, feel free to weld them in the fixture.

    10. Remove the frame from the fixture. You will install the seat stays later.

    11. Finish brazing out of the fixture or, if tig welding, finish welding any remaining joints using a proper weld sequence.

    12. Chase & face BB; ream & face head tube.

    13. Check frame alignment.

    Here’s the key: it is easy to align any conventional frame that NEEDS* it as long as the seat stays are not installed. If you have head tube twist or if the seat tube and the head tube are not parallel with each other, it is easy to correct now. Same with chainstays. Spacing, parallelism, and centerline are easily corrected without the seat stays installed. Once you install the seat stays, everything you do to align a frame gets a lot harder as the stays communicate any adjustments to the dropouts. If you remove the frame to check alignment before brazing/welding has been finished, you’re just chasing your tail. This is especially true at the bottom bracket since any heat application warps the BB faces and flipping the frame on an alignment table doesn't mean squat because the faces may not be warped symmetrically. You might get lucky, but that's what it is. BTW, Witch wanding or apply soft heat on steel frames in certain areas of the frame is a better way of bringing a frame into alignment than cold setting.

    14. Once the frame has been aligned to your satisfaction, put it back into the fixture and lock it down.

    15. Miter, prep, and check seat stay fit.

    16. If seat stays are correct, tack or weld them out.

    17. Check final alignment.

    Note: I make it a point to install any braze-ons BEFORE I miter the tubes if possible and certainly before I install the affected tube in the fixture. Braze-ons will distort the tubing and it can make your life miserable doing it after the frame is built because it can affect your alignment.

    *you as the builder determines what needs alignment to meet your own specs and what doesn't.
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  6. #6
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    Big Thanks to Walt and DWF.

    I like the tip to do brazons prior to completing the frame because it makes sense plus it will be easier for me to tig braze them on my table vs. doing it on the complete frame.

    I will also likely face my BB after I do the chain stays, down tube, and seat tube. All my alignment comes from the faces on the shell and as such an early face should help as I shoot for perfection.

    My last frame was within 2mm in all measurements and within 1mm in terms of head tube twist. The thing is on the last frame I did more then a few extra passes with the TIG to get things right. My welding skill is improving so I think I can get alignment without as many extra passes.

  7. #7
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    Big Thanks to Walt and DWF.

    I like the tip to do brazons prior to completing the frame because it makes sense plus it will be easier for me to tig braze them on my table vs. doing it on the complete frame.

    I will also likely face my BB after I do the chain stays, down tube, and seat tube. All my alignment comes from the faces on the shell and as such an early face should help as I shoot for perfection.

    My last frame was within 2mm in all measurements and within 1mm in terms of head tube twist. The thing is on the last frame I did more then a few extra passes with the TIG to get things right. My welding skill is improving so I think I can get alignment without as many extra passes.

  8. #8
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    This post will be printed out and pinned to my shop wall (short-term memory loss). Thanks you guys for spelling it out so well!

    DWF's process made me want to ask: how many on the list actually weld as much as possible in the fixture? I know he's an amazing welder and preferential to Anvil fixtures where welding in the fixture may be possible, but with my Access65 I can't see twisting and turning it very easily to weld it up well. I love my fixture, but it's way more difficult than taking it out and using a rotating bike stand. Also, you can't use heat sinks when in the fixture obviously.

    Does the frame have the ability to move significantly out of alignment with tight miters and good tacking (barring any major F-ups of course)? I was under the impression that most builders tack it up, then take it out of the fixture to complete the welds. My sample size is very low, but it appears to me that my sub-optimal mitering (as Walt said above) is the main reason for any alignment issues I experience.

  9. #9
    DWF
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    Quote Originally Posted by Meriwether
    This post will be printed out and pinned to my shop wall (short-term memory loss). Thanks you guys for spelling it out so well!

    DWF's process made me want to ask: how many on the list actually weld as much as possible in the fixture? I know he's an amazing welder and preferential to Anvil fixtures where welding in the fixture may be possible, but with my Access65 I can't see twisting and turning it very easily to weld it up well. I love my fixture, but it's way more difficult than taking it out and using a rotating bike stand. Also, you can't use heat sinks when in the fixture obviously.

    Does the frame have the ability to move significantly out of alignment with tight miters and good tacking (barring any major F-ups of course)? I was under the impression that most builders tack it up, then take it out of the fixture to complete the welds. My sample size is very low, but it appears to me that my sub-optimal mitering (as Walt said above) is the main reason for any alignment issues I experience.
    I'm not a hardcore weld in the fixture advocate, but I don't buy into the old school you can't weld in the fixture either. At least when it comes to welding. Brazing soaks a lot more heat over a greater section of the tube and that can cause problems for joinery in the fixture with lug building or fillet brazing. Generally, I do what's easier for me and allows me to do my best work. If it's easier for you to tack in the fixture and weld it on the bench, then that's what you should do. The deal with how I describe the building process supports either method. My real point is that folks handle the frames too much and they do it for a variety of questionable reasons.

    It's like this: every time you heat the BB it distorts. Tack/join the seat tube to the BB shell and it distorts; DT to the BB shell, it distorts; chainstays to the BB shell and it distorts. Each other affects the BB shell a different way but they all distort it. To get a meaningful reading on your alignment at that point means your facing the shell or you're ASSUMING that the distortion is symmetrical on the shell side to side. Are you going to face that BB shell at every check? Hell no, it'd be silly right? But, there is no good way of checking alignment without facing the BB (or the HT for you HT origin alignment folks) so I follow the steps I outlined above.

    As far as mitering, anytime you do heat joinery it's going to contract/shrink at the joint. If your miters are tight you can control & predict that shrinkage. If they're loose you'll never be able to figure out what the hell is going on unless you leave them loose the exact same way every time. That's pretty hard to do in a bespoke builder's shop where each frame is different, but often used in production. IMO, it's much better to fit your miters as tightly as possible and always use the adjoining tube as the go/no-go gage.

    In other words, focus on your miters and your joinery and save the jewelry making for later in your career after you've mastered the basics. Nothing grates on me more than seeing a frame where the builder spent more time adding magpie bait or "color, depth, and texture" to a frame than they did learning the joining procedure they employed to build it. That's not pointed at anybody, it was just a wee bit of a rant was coming on.
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  10. #10
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    Thanks for the elaboration. I understand better your process.
    I'll experiment with welding as much as possible in the fixture and will do my best to not sprinkle sugar on **** (although my dogs would love that) before becoming an expert at mitering and TIG.

    Any way you'd briefly explain "witch wanding" a frame into alignment...? I have no idea what you mean but am really interested since cold-setting just doesn't feel right.

  11. #11
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    Great post, Don

    I had never really considered the "chasing my own tail" bit with all my preliminary alignment checks (for what it's worth, I'm ending up in the same place, I think, because I do face the shell and check everything before the seatstays go on). And of course the bottom line is if the bike goes straight and handles like it should, the process is working - but I think I'm wasting a lot of time.

    I have never noticed (checked before and after) any movement due to brazeons, but I think your method is probably better anyway. Man, every time I think I know how to do something, someone here comes along and makes me feel like a hack (especially as I fumble my way through the KVA nightmare...) But I love it, I've learned so much from y'all (beginners and pros alike) - what an awesome forum.

    -Walt

  12. #12
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    Quote Originally Posted by Meriwether View Post

    DWF's process made me want to ask: how many on the list actually weld as much as possible in the fixture? I know he's an amazing welder and preferential to Anvil fixtures where welding in the fixture may be possible, but with my Access65 I can't see twisting and turning it very easily to weld it up well. I love my fixture, but it's way more difficult than taking it out and using a rotating bike stand. Also, you can't use heat sinks when in the fixture obviously.
    If I had an Anvil jig I'm thinking I could weld the whole thing in the jig. With my back plat style jig with only 6" of stand off I'm lucky I'm luck if I can get tacks all the way around it.

  13. #13
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    I could weld the ST/DT joint in the jig but I still don't understand why I would want to do that. What is the advantage of doing the complete weld in the jig?

    On my last weld, I checked alignment after 40% of the weld was complete and again after 60% of the weld was complete. These checks allowed me to alter the pacing and direction for the welding such that when the joint was 100% complete it was in alignment. If you are welding in the jig do you check along the way our just at the end?

    I think that even with perfect miters and a perfect jig welding without checking alignment will not produce alignment on it's own. If you do the entire weld in the jig how often do you have to cold set?

    I can see what DWF means by the faces of the shell changing and about how the frame becomes stiffer once the seat stays are installed but I don't understand why one would want to do the full weld in the fixture rather then simply tacking in the figure (unless is is just to save time).

  14. #14
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    Quote Originally Posted by febikes View Post
    I could weld the ST/DT joint in the jig but I still don't understand why I would want to do that. What is the advantage of doing the complete weld in the jig?

    On my last weld, I checked alignment after 40% of the weld was complete and again after 60% of the weld was complete. These checks allowed me to alter the pacing and direction for the welding such that when the joint was 100% complete it was in alignment. If you are welding in the jig do you check along the way our just at the end?

    I think that even with perfect miters and a perfect jig welding without checking alignment will not produce alignment on it's own. If you do the entire weld in the jig how often do you have to cold set?

    I can see what DWF means by the faces of the shell changing and about how the frame becomes stiffer once the seat stays are installed but I don't understand why one would want to do the full weld in the fixture rather then simply tacking in the figure (unless is is just to save time).
    I think once you have an established weld process that is consistent you can weld as much as you want in the fixture. A good fixture can do a fair bit to control distortion as well. So that can help your battle. If you go about your welding in a manor to balance one pass with another everything should come out pretty damn close. I could see where being a smooth and consistent welder would help a ton as well.

  15. #15
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    Total newb here....how much would a Henry James alignment table go in remedying distortion problems?

  16. #16
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    From what I understand it is better to prevent the misalignment than to fix it.

  17. #17
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    I am not a fan of welding in a jig unless properly designed to do so allowing the tube to slip in the fixture. Again I am not the best tig welder either and take too long in my opinion. Brazing especially as it will distort and implode the tube that the mitered tube butts up against. If the say HT is at a fixed angle to the TT and the TT is allowed to slip in the fixture that works pretty well but I just don't see the need to do that on a single assembly. I have seen HT, DT and TT assembly's done at one time and that would work for that helping to keep both DT and TT in alignment with minimal distortion to the HT. That assembly could then be put in the jig, TT and ST welded again allowing the front assembly to slide forward in the jig as the joint is heated and yet keep the HT on the same plane as the ST.

    I am not a fan of cold setting either. Taking the tube to it's yield point just doesn't make since to me. I align with heat. It doesn't take much at all usually to get the tube to move allot. Resisting that movement and then letting it cool works very well and is controlled alignment where you want it to move and not where the fulcrum point is necessarily. You would be surprised how much a frame will move with even a Bic lighter taken to it.

    It is not too late to align a frame with the SS on. You can file on the drops which I don't like to do. I use my 1" tool steel bar in the drops. Swing it to the ST or BB and see how far it is off. This is done making sure the rear is on center line of the main triangle plane. Again as you heat a stay you will see the bar move to the opposite side. Resist that movement. Of course I am talking about fine adjustments with minimal, non colored heat in selected points of non stress. You can get the bar to move at the ST a couple of MM's easily. Mine are seldom off by more than a few thousandths off at the DO. I usually have the bridge and canti's on before I attach to the ST.

    I also mark where my bottle bosses go on while I the tube is in the miter fixture. Solder them on before the final miter and assembly. Done correctly there is little stress put in the tube putting on braze ons after the frame is together but it does put some in so why not limit what you can. I too have never had one go out of alignment putting on a braze on after the frame was welded. I have had a frame crack even taking a center punch to the DT to install a WB boss. Not one of mine but a guy who brought me his cross bike and wanted WB braze on put on his old frame. Only had that happen once but that leads to saying I hope it doesn't happen again and I can't be responsible if it does happen. I was so surprised and with just a center punch, the spring loaded type. Obviously the frame was under extreme stress.

    There are many ways to skin a cat. Some are more productive than others and it is up to the builder to decide on what is good enough for the money that is being charged. In production heavier tubes are used to allow for getting frames to in and out of the fixtures in 20 secs. and onto the next operation. I've seen some horrendous stuff in the Raleigh factory when I was a production consultant for them.
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  18. #18
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  19. #19
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    Witch Wanding Query.

    Best way to play with this one is to get an old steel fork that is true and heat up a little area of 1 leg (either front or rear side) and let it cool, then check its alignment. See if can get it back to true again .. its fun.

    Eric

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