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  1. #1
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    Flat surface and alignment table?

    Hey community - I am trying to make a future proof, limited budget decision here.

    Could this table be a tool I can and will use for the start and the rest of a frame building career? Especially if combined with an alignment kit like the one pictured by Mr. Wolf tools?

    Basically I am looking for confirmation on the direction here. I have yet to finish my first frame, and it is very questionable that I will ever try making money with building frames.
    So buying an expensive frame fixture is not going to happen at this point, as I want to learn building by making my own frames for now...
    At this point I can justify the expense of a flat surface table with the alignment kit, provided it is seriously useful (meaning necessary) down the road in case I want to ever become a pro.

    That table itself is 115/100cm and such a table can be had for 300-500 bucks over here. Or are there better options I should look at? Alignment kit is another 1400 bucks.

    Flat surface and alignment table?-%24_86.jpg
    Flat surface and alignment table?-22042279_1950814898522371_6487626356221349745_o.jpg

  2. #2
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    I have a Nortac frame jig, which ran me $1100 with a fork jig, so take that as a data point, but... Several years in, I'm using a 1-1/4" thick slab of countertop granite, supported by 1-1/4" oak planks on top of a pair of heavy duty saw horses. I clamp on a bottom bracket "whipping post" to one corner (where one of the planks also supports) and have a scratch gage to judge height. Turning the frame over on the whipping post, then check with the scratch gage again. Cold set as necessary. All in with those items I think I'm under the $1400 you listed. Many ways to skin that cat.

  3. #3
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    You do not need an alignment table. You can check alignment with a variety of extremely low tech tools (nothing more than a flat piece of stock and a ruler/calipers is good enough).

    You can obviously use the flat table to build on as well using v-blocks or similar, but IMO that's enough of a PITA that you'd be better off just building yourself a jig from 8020.

    So to answer the question, don't waste your money on a big heavy flat table. Alignment to within less than 5mm or so isn't critical anyway, and you can check it easily with a variety of homemade junk you already have sitting around.

    -Walt

  4. #4
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    Walt, are you saying forget about cold setting, and learn to align with welding a second pass then?

  5. #5
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    Quote Originally Posted by Sepp View Post
    Walt, are you saying forget about cold setting, and learn to align with welding a second pass then?
    Here's the thing - with modern (mountain bike, at least) tubing, the only thing that happens when you put a huge lever on a frame and try to cold set it is that you squish the BB shell a little bit. Then it looks like maybe you did something, but if you go back and re-face the shell you'll realize all you actually accomplished was to damage it.

    Now, if you're building with 25.4mm tubes and lugs, you can move stuff around plenty. All these alignment tables/tools are remnants of that era. Remember that the stiffness of a tube roughly doubles when you increase the diameter 10%...

    Alignment is basically done by doing good miters and joinery. Once you've got a 38mm downtube in there, you're not moving that sucker.

    You can do some witch-wanding and running second passes (I occasionally do a little of both of those) and get things to move some. But cold setting for main triangle tubes? Forget it. You're much better off just leaving whatever misalignment is there and riding the bike.

    Remember also that when you face a (19mm radius) shell, you're only going to get the faces parallel to within plus or minus a few thousandths. Translate that out over the ~750+mm of distance to the head tube and you've got to multiply your .003" error by 40 or so - so your error out at the head tube is something like plus or minus .120"/3mm. So there's no point in trying to align better than that anyway.

    -Walt

  6. #6
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    I didn't even get to tell you what i am up to, so how'd you guess it?...MTB with 38mm DT it is

    That's a better explanation than I could have hoped for.
    Thanks

  7. #7
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    Walt just relayed my feelings on frame alignment almost exactly. I happen to have an accurate frame jig, and I do 98% of my welding inside the fixture. I find this makes the frame come out extremely straight (along with smart weld sequences) and the idea of cold-setting a mountain bike frame makes me cringe.

    As far as what to invest in? Make an 80/20 beam style jig if you want a jig. Very little material, and accurate enough for many things. Making accurate miters is the highest priority in my opinion, but that's it's own rabbit hole.
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  8. #8
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    the 8020 route crossed my mind several times, but then you need the cones and other parts, and without access to a lathe/mill is too time consuming/expensive.

    I hear you on the smart weld sequence - is this every builders personal secret, or why can't I find anything more specific info on that?


    Quote Originally Posted by Erichimedes View Post
    Walt just relayed my feelings on frame alignment almost exactly. I happen to have an accurate frame jig, and I do 98% of my welding inside the fixture. I find this makes the frame come out extremely straight (along with smart weld sequences) and the idea of cold-setting a mountain bike frame makes me cringe.

    As far as what to invest in? Make an 80/20 beam style jig if you want a jig. Very little material, and accurate enough for many things. Making accurate miters is the highest priority in my opinion, but that's it's own rabbit hole.

  9. #9
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    Quote Originally Posted by Sepp View Post
    the 8020 route crossed my mind several times, but then you need the cones and other parts, and without access to a lathe/mill is too time consuming/expensive.

    I hear you on the smart weld sequence - is this every builders personal secret, or why can't I find anything more specific info on that?



    Cones can be sourced from e bay, there is at least one frame builder that makes parts to spec. and cones don't have to be cones per say. The shoulders of large diameter sockets could work for instance. Some builders (not very many) clamp the bottom bracket in a vice and start tacking parts on. Some rudimentary tools ( a straight edge and a string line) to check for straightness and Bob's your uncle. Building one frame can be as simple or as complicated as you wish to make it. Weld sequence is a moving target, but you'll get a general idea as you build more frames and figure out how they react to weld placement and heat input. The better the fit up the less stuff moves around. My two pesos.
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  10. #10
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    If building an 8020 jig is beyond your motivation level, you are really going to struggle with a bike frame. All the parts can be (with a little research) purchased, there's really no need for a lathe or any fancy tools.

    I use this sequence:
    -Completely weld in the seat tube.
    -BB shell/DT NDS
    -BB shell/DT DS
    -TT/ST bottom 1/4
    -TT/ST top 1/4
    -DT/HT top 1/4
    -DT/HT bottom 1/4
    -TT/HT bottom 1/4
    -TT/HT top 1/4
    -DT/ST NDS
    -DT/ST DS
    -ST/TT NDS
    -ST/TT DS
    -TT/HT NDS
    -TT/HT DS
    -DT/HT NDS
    -DT/HT DS

    At the rear end, sequence matters less and it's possible to cold set individual parts (chainstays) because they're comparatively tiny.

    Keep in mind that what works for me might or might not work for you.

    -Walt

  11. #11
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    Skip the 80/20 and copy the jig that Blacksheep uses. It's made from cold rolled steel.

    Some smart ordering of pre-cut lengths from your steel source and you could build it with nothing more than a hand drill.

    I have built a couple frames so far on mine. I've skipped the headtube cones and bb cones, for these i drill a hole in them then bold them straight to the jig. It's not a production environment so it doesn't matter that it's slow to load and remove.

  12. #12
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    Quote Originally Posted by Walt View Post
    If building an 8020 jig is beyond your motivation level, you are really going to struggle with a bike frame. All the parts can be (with a little research) purchased, there's really no need for a lathe or any fancy tools.

    I use this sequence:
    -Completely weld in the seat tube.
    -BB shell/DT NDS
    -BB shell/DT DS
    -TT/ST bottom 1/4
    -TT/ST top 1/4
    -DT/HT top 1/4
    -DT/HT bottom 1/4
    -TT/HT bottom 1/4
    -TT/HT top 1/4
    -DT/ST NDS
    -DT/ST DS
    -ST/TT NDS
    -ST/TT DS
    -TT/HT NDS
    -TT/HT DS
    -DT/HT NDS
    -DT/HT DS

    At the rear end, sequence matters less and it's possible to cold set individual parts (chainstays) because they're comparatively tiny.

    Keep in mind that what works for me might or might not work for you.

    -Walt

    FANTASTIC!

    Why are you welding the DT in two stages to the BB while you do all the other tubes in four?

    I somewhere read to place tacks first on all obtuse angles, and then on acute angles. Do you tack on the centerline plane of a frame first and then on the sides (so a total of four tacks around a tube)?

    Great info.Thanks so much.

  13. #13
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    Quote Originally Posted by shirk View Post
    Skip the 80/20 and copy the jig that Blacksheep uses. It's made from cold rolled steel.

    Some smart ordering of pre-cut lengths from your steel source and you could build it with nothing more than a hand drill.

    I have built a couple frames so far on mine. I've skipped the headtube cones and bb cones, for these i drill a hole in them then bold them straight to the jig. It's not a production environment so it doesn't matter that it's slow to load and remove.
    Any picture you could share of yours? Or the Blacksheep jig?

  14. #14
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    Quote Originally Posted by life behind bars View Post
    Cones can be sourced from e bay, there is at least one frame builder that makes parts to spec. and cones don't have to be cones per say. The shoulders of large diameter sockets could work for instance. Some builders (not very many) clamp the bottom bracket in a vice and start tacking parts on. Some rudimentary tools ( a straight edge and a string line) to check for straightness and Bob's your uncle. Building one frame can be as simple or as complicated as you wish to make it. Weld sequence is a moving target, but you'll get a general idea as you build more frames and figure out how they react to weld placement and heat input. The better the fit up the less stuff moves around. My two pesos.
    Thanks for reminding me of how simple it can be - I will build my first frame rather quick and simple because chances are I will redo it (didn't we all) anyway.

  15. #15
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    Quote Originally Posted by Sepp View Post
    FANTASTIC!

    Why are you welding the DT in two stages to the BB while you do all the other tubes in four?

    I somewhere read to place tacks first on all obtuse angles, and then on acute angles. Do you tack on the centerline plane of a frame first and then on the sides (so a total of four tacks around a tube)?

    Great info.Thanks so much.
    Some of it is done in the fixture and some not. There are 4 stages to the DT/BB area, but 2 of them are really mostly welds to the ST, so you might have missed that part.

    I never tack, or stop/start on the centerline if I can help it. That's where stress risers can cause problems. I tack at 1:30/4:30/7:30/10:30. Tacks go where they'll hold things where you want them (ie, don't put a tack in a place that will cause the tube to pull away from where it's supposed to be), so there's no hard and fast rule about obtuse vs acute. 4 tacks for main triangle stuff, fewer is fine for chainstays and seatstays in most cases.

    -Walt

  16. #16
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    https://www.instagram.com/p/BOlz-S0gB6M/

    https://www.instagram.com/p/BYEcjERniEx/

    https://www.instagram.com/p/BMAUUWBgT7y/

    https://www.instagram.com/p/BMATvn4Ao4Y/

    https://www.instagram.com/p/BGNGTMnwBjp/

    There are some images.

    The smart part about it is that you are using the flat faces to key each piece off itself. You also build with the headtube set vertical instead of in the actual angle of the finished frame.

  17. #17
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    Check out the Bicycle Academy jig:

    https://thebicycleacademy.org/produc...me-fixture-kit

    Iíd get or make a frame fixture first and not worry about alignment, other than by taking notes on what happens when you try different tacking and welding sequences. I differ from Walt in where I tack but not too much in welding sequence.
    Think about it like this: pull the tubes together in a way that they donít want to go sideways. Welding tops and bottoms first holds the tubes in place so when you weld the sides it all should stay straight.
    Tight miters are where to spend your time and how you get them less than paper thin without having to file to fit too much.

    I basically use my alignment table for checking layout, phasing of s-bend stays and bent tubes, and centering the chainstays after welding (easily moved unlike the front triangle). But you could likely get away with something way cheaper than what I have, granite table top or the like.

    I would agree with others Iíve heard say that you have to have a frame pretty far out of alignment for anyone to notice it. Head tube twist being the most noticeable.


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  18. #18
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    Those Academy jig's are only inexpensive when you compare them to something like an Anvil.

    I have about $250 Canadian in materials into my copy of the Blacksheep jig. That's 165 euro vs 850. And I believe with the Academy you still need to buy the main steel body tubing.

  19. #19
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    Yeah, I have looked at those academy jigs before, and realized that they're not really cheap, especially since one needs to order additional parts.

    Given all the custom machined parts I'd consider the Anvil a much better deal, and you're buying into decades of fixture making experience...

    I will stick with wooden jigs for my first project, and decide on the fixture thing after that.


    off topic: do you have any tips on how to clean tubes on the inside further down from the miters. I have cable exits that are welded - I have tried to clean with tube brush and acetone/alcohol, but I still get quite some oxidation going on in there. No backpurge though.
    Throwing the tubes and letting them soak overnight in some detergent maybe?

  20. #20
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    I haven't aligned a bike since 2009.

  21. #21
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    Quote Originally Posted by Sepp View Post
    off topic: do you have any tips on how to clean tubes on the inside further down from the miters. I have cable exits that are welded - I have tried to clean with tube brush and acetone/alcohol, but I still get quite some oxidation going on in there. No backpurge though.
    Throwing the tubes and letting them soak overnight in some detergent maybe?
    Your cable exits are fine if the tube is a tiny bit dirty. Don't worry about it. Anything tiny that you TIG weld is going to get wicked hot, so unless you're backpurging, you should expect some oxidization on the backside of the weld.

    Most steel tubes (intended for bikes, that is) basically just need a quick mechanical cleaning, you don't even really need to do any alcohol, let alone acetone. If you're taking a tube brush and solvent to the tube, you're getting it plenty clean.

    -Walt

  22. #22
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    So we are talking mostly MTBs, yes? I get it, I've made a somewhat misaligned frame (via noob incompetence with composites, not from weld pull), it rode fine.

    But I'm not rocketing down mountain pavement doing 50 mph.

    I seem to recall Calfee (or someone?) claiming that the tire contact center line has to be within +/- 1.5mm if you're gonna go fast.
    Disclaimer: I run Regular Cycles (officialy in 2016, functionally in 2020).

  23. #23
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    Quote Originally Posted by Walt View Post
    Your cable exits are fine if the tube is a tiny bit dirty. Don't worry about it. Anything tiny that you TIG weld is going to get wicked hot, so unless you're backpurging, you should expect some oxidization on the backside of the weld.

    Most steel tubes (intended for bikes, that is) basically just need a quick mechanical cleaning, you don't even really need to do any alcohol, let alone acetone. If you're taking a tube brush and solvent to the tube, you're getting it plenty clean.

    -Walt


    Great, I'll stop worrying then.

    There are plenty of other reasons why my first frame will collapse before rust-through anyway. )

  24. #24
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    Quote Originally Posted by Drew Diller View Post
    So we are talking mostly MTBs, yes? I get it, I've made a somewhat misaligned frame (via noob incompetence with composites, not from weld pull), it rode fine.

    But I'm not rocketing down mountain pavement doing 50 mph.

    I seem to recall Calfee (or someone?) claiming that the tire contact center line has to be within +/- 1.5mm if you're gonna go fast.
    Bullshit. Go grab your old road bike and dish the wheel out a couple of mm. Hell, dish it out 5mm. Go ride it.

    You won't be able to tell. *Maybe* you could tell on 19c tires at 200 psi, riding with no hands or something. So if you are descending mountain passes no hands on your track bike, that could be a problem.

    Alignment *does* matter, of course. But the precision people claim to be aligning to (often under 1mm) is 1: not possible due to the inherent errors in measurement, and 2: not useful to make a bike that rides nicely.

    -Walt

  25. #25
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    Quote Originally Posted by Meriwether View Post
    I differ from Walt in where I tack but not too much in welding sequence.
    Think about it like this: pull the tubes together in a way that they donít want to go sideways. Welding tops and bottoms first holds the tubes in place so when you weld the sides it all should stay straight.
    I see two different strategies there, assuming that the welds are running from one tack to another, right (rather than starting a weld in between two tacks, and running the bead over the next tack)?

    - purely from a tacking view of things it makes more sense to me, but...since the first bead around the tube would be asymmetric, wouldn't that pose a bigger risk of pulling the tube out of the center plane?

    Yeah too much theory vs going to my workshop and trying it out, I know...sorry...

  26. #26
    pvd
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    On a well designed bicycle, the second you apply a load to it, the wheels go out of alignment. It's a completely over rested metric that has little use when riding.

  27. #27
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    Quote Originally Posted by Sepp View Post
    I see two different strategies there, assuming that the welds are running from one tack to another, right (rather than starting a weld in between two tacks, and running the bead over the next tack)?

    - purely from a tacking view of things it makes more sense to me, but...since the first bead around the tube would be asymmetric, wouldn't that pose a bigger risk of pulling the tube out of the center plane?

    ..
    Iíll weld between the vertical tacks for the 10-2 and 4-8 spots in the fixture and then remove to weld the rest when itís kinda more locked in place. Iím not recommending this unless you have good welding experience since you can burn a hole fast when not starting at a tack.

    Iím pretty sure EVERY builder has their own method which kinda proves the point that it doesnít matter much which way you do it. Stress risers are something to consider as Walt pointed out but collectively we have little data to show one way works better than another (as far as frame failures). As far as i know at least and would love to hear if thatís wrong!


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