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  1. #1
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    First time frame build, with CAD drawing! Would love feedback

    Hello everyone,

    Ive been lurking in this forum for some time now, following the stuck threads, other beginners, etc and now Im finally going for it! I have access to a nice jig, TIG welder, and have fabricated my own tubing notcher on a metal lathe. I have started making maple tubing blocks, and still havent decided if I need V-blocks since I can use the jig to mock up the tubing (I think).
    I still need plenty more practice on the thin-metal TIG welding, and the notcher needs dialed in, but in the meantime, Ive been working on my plans. Ill post a picture and geometry chart below, along with the tubing I have already purchased. Basically, Ive designed a 1x10 (no derailleur or chain guide, 32t narrow/wide ring only) hardtail around a 100mm fork (probably Reba) with aggressive geometry that can be ridden hard. I weigh 220# and I want this bike to be strong and reliable, which is why Im not concerned about weight. I am interested in any feedback you guys have about anything I have posted here, but I do have some specific questions as well:

    Is it possible to notch my stays and TIG weld my dropouts, or is it recommended to braze them on a plate dropout?
    Is this frame ok without ST sleeve? I know it is highly recommended around here, but with a 1.6mm wall thickness on my ST, maybe its ok?
    Id like a little lower standover, would it be safe to drop TT @ ST about 1.5 and add a gusset?
    With the offset ST, do you recommend any gussets at BB region?
    I dont have a wheel to measure at the moment, and I settled on 29.25 Dia. for the design; is that about right?
    With my setup, is my headtube long enough to be strong (105mm)? About between TT and DT
    Do I need brake support w/ paragon dropouts having the brake mount built into the dropout?

    As you can see below, I used the 2d sketch feature in Inventor since BikeCAD wouldn't play nice with my computer, and Im familiar with the program. So far, so good!
    First time frame build, with CAD drawing! Would love feedback-geometry.jpg
    First time frame build, with CAD drawing! Would love feedback-frame-sketch2.jpg

    My next steps are to 1. Complete a chainstay drawing to make sure I can squeeze everything in there. 2. More TIG practice 3. Finish tubing blocks.

    Thank you guys for any feedback! I already bought materials for this, but if there are any glaring errors, I'm happy to return and buy the right stuff where needed.

  2. #2
    Nemophilist
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    Hey;

    Enjoy the dive!

    Noob to noob answers to your noob questions;

    1) No reason not to TIG as long as you do not plan to build up or fill a lot. Filling with TIG gets things too hot.
    2) .063 should be PLENTY thick for a straight joint. In fact, you might drill and tap them in!
    3) Mr. Walt always said no more than 2" or so of unsupported length above the TT, if memory serves me correctly. You may have some leeway with that thick tube, but no sense pushing your luck either.
    4) Probably not necessary, but it certainly couldn't hurt.
    5) For me? No wheel = no build. That's just asking for trouble. I take the dummy approach. Once you've done a few dozen, you can slide through on your vast experience with such stuff.
    6) I would ALWAYS make my HT as long as I could. I'm uncut steerer size, so it is never a problem for me.
    7) No.
    Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
    - John Hajny, a.k.a. TrailMaker

  3. #3
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    Thanks for pointing out that seat tube, I've never noticed it before. The thick section looks like its 75mm long so and inch and a half would still be to the thick part. Tigging the ends of the stays to fill them in does put a lot of heat in them. Sometimes I use a pulse setting of 30pps and lower the heat and build up the filler, then go over it hotter to blend it in. May just be easier to use silver like fillet pro. Those paragons are stainless so no brass.
    cheers
    andy walker

  4. #4
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    I'd probably lean towards at least a 38.1 downtube. Are you designing around the fork sagged?

  5. #5
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    Random thoughts!

    -.6mm seatstays are not going to be fun to TIG weld if you are not pretty good at TIG in weird angles/tight corners on thin-to-thick. Get some .8mm or even .9mm if you can find them.

    -I'd go 38mm on the downtube as Dr. W suggests.

    -The 1.6mm seat tube is thick enough to weld directly to BUT keep in mind that if you are throwing lots of heat at it it'll distort a bit more than a sleeved joint will - meaning more work to ream back to vaguely round to get a post in.

    -42cm chainstays on a 29er are not super hard to do but you are going to be cutting things very close on clearance so mock up your chainstay assembly with your actual cranks and ring in hand to make sure you've got something that will work.

    -Yes, you can lower the toptube and add in a brace. Be aware that unless you do it carefully you may end up pulling the seat tube forward at the top and have odd problems with the effective angle/saddle positioning.

    -You do not need any extra bracing for the brake side stays with a dropout-integrated disc mount.

    -Yes, you can slot and TIG, assuming you are decent with the torch. I do it on basically all my frames.

    Keep us updated!

    -Walt
    Waltworks Custom Bicycles
    Park City, UT USA
    www.waltworks.com
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  6. #6
    The cat's name is jake
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    A 1.6mm thick Seat tube sounds AWFULLY thick to me. I'm not sure why you'd want it that thick, to be honest. Are you relying on the material thickness to maintain roundness after welding? I'd consider alternately making a heatsink instead, and then honing the bore to fit your seatpost and using a thinner seat tube. With TIG welding, differences in base metal thickness cause as much trouble as anything. Thin to thin is easy, but thin to thick can be more challenging in many cases (though not all), and can cause problems after the fact.

    I'd also consider giving yourself a little more extension on the HT, from the intersection of your DT especially, but your TT as well. Welding the DT and TT will really want to distort the HT when the tubes intersect close to the edges. This is still the case for me, even though I've welded 2-4+ frames a day for many years.

    I second John's (TrailMaker) sentiment about the wheel. It is important to be able to reference the wheel for several reasons. One is simply for proper placement of bends and bridges, but it also is very helpful for alignment purposes. You will want the wheel centered with respect to the seat tube, but also balanced between the seat and chainstays. It is very handy for this, as you can use a caliper to measure between the rim and the stays, and sight down the back of the wheel up through the seat tube and head tube. Furthermore, it would be good to either have the cranks, or know the chainline and where the end of the crankarms sit relative to something you can reference, such as the edge of the BB shell. Sometimes, the crank may sit such that your heel will clip the chainstay if it sits out further than necessary. Having the crank can help you determine whether there is sufficient room for heel clearance (and of course ring clearance).

    That is a nice looking design otherwise, and you appear to be well on the way to making an excellent bike. Good work!

  7. #7
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    Thanks for the replies everyone! As far as the seattube, I thought it sounded pretty thick as well, but wouldn't a sleeve present essentially the same problems (thick to thin)?
    On the headtube, I think I am going to go longer, and further from the ends to prevent warpage. Unfortunately, when I just throw a 130mm HT into my drawing, my reach and stack get pretty whacked out, so I need to do some thinking geometry-wise there.

    I'll make sure to get my hands on wheels and cranks before going too much further thanks to people's advice here.

    I'm totally up for making the bike stronger by adding a bigger DT, but I have run into another problem: when I add a straight 35mm DT, it looks like the fork crowns may not clear. I can't find a bent 35mm DT that is in stock anywhere. Is there a source for any CAD files on common fork crowns? Seems like getting my hands on the fork sooner than later wouldn't hurt, either.

  8. #8
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    Quote Originally Posted by dr.welby View Post
    I'd probably lean towards at least a 38.1 downtube. Are you designing around the fork sagged?
    Looking at working out the DT upgrade. I am not designing around the fork sagged, but I have been keeping it in mind. Do most companies list their static geometries? I have been using bikes that I like to inform my design, but can see the value in designing around sag as well. Do most of you guys do that for front suspension hardtails?

  9. #9
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    Quote Originally Posted by Walt View Post
    Random thoughts!

    -.6mm seatstays are not going to be fun to TIG weld if you are not pretty good at TIG in weird angles/tight corners on thin-to-thick. Get some .8mm or even .9mm if you can find them.

    -I'd go 38mm on the downtube as Dr. W suggests.

    -The 1.6mm seat tube is thick enough to weld directly to BUT keep in mind that if you are throwing lots of heat at it it'll distort a bit more than a sleeved joint will - meaning more work to ream back to vaguely round to get a post in.

    -42cm chainstays on a 29er are not super hard to do but you are going to be cutting things very close on clearance so mock up your chainstay assembly with your actual cranks and ring in hand to make sure you've got something that will work.

    -Yes, you can lower the toptube and add in a brace. Be aware that unless you do it carefully you may end up pulling the seat tube forward at the top and have odd problems with the effective angle/saddle positioning.

    -You do not need any extra bracing for the brake side stays with a dropout-integrated disc mount.

    -Yes, you can slot and TIG, assuming you are decent with the torch. I do it on basically all my frames.

    Keep us updated!

    -Walt
    I'm going to look into thicker stays. Thanks for the suggestion, I can imagine that would be a challenge, especially after my TIG practice session yesterday!

    I think I'm going to avoid braces wherever possible, so I may shorten the ST length just a bit, and lower the TT a bit and call it good.

    Pretty excited I don't need to brace with those dropouts- I like how they have the brakemount and hanger built in to keep things a bit more simple for my first build.

    I will keep you guys updated! Thanks again

  10. #10
    The cat's name is jake
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    Here's a bent 1.5" DT.

    NOVA CRMO 38mm DOWNTUBE FOR MTB/29er WITH BEND :: 38.1mm DOWN TUBES :: ROUND TUBES :: MAIN TUBES :: TUBES STEEL :: Nova Cycles Supply Inc.

    I've used it - it's alright.

    For entry level seatstays, I'd consider something in the neighborhood of .035". Dead easy to work with in multiple ways - easy to bend, easy to weld, easy to source material. Durable thickness for most types of riding save the most aggressive.

    Regarding sagged vs. unsagged, I personally work with the unsagged measurement, just because that's the easiest for me to work with and think about, experience wise. I know what a bike with XX head angle, and XX fork travel/A2C feels like. I think that is most typical, as far as listed figures are concerned.

  11. #11
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    Quote Originally Posted by BungedUP View Post
    Here's a bent 1.5" DT.

    NOVA CRMO 38mm DOWNTUBE FOR MTB/29er WITH BEND :: 38.1mm DOWN TUBES :: ROUND TUBES :: MAIN TUBES :: TUBES STEEL :: Nova Cycles Supply Inc.

    I've used it - it's alright.

    For entry level seatstays, I'd consider something in the neighborhood of .035". Dead easy to work with in multiple ways - easy to bend, easy to weld, easy to source material. Durable thickness for most types of riding save the most aggressive.

    Regarding sagged vs. unsagged, I personally work with the unsagged measurement, just because that's the easiest for me to work with and think about, experience wise. I know what a bike with XX head angle, and XX fork travel/A2C feels like. I think that is most typical, as far as listed figures are concerned.
    Thanks! That's the DT I wanted, but it's out of stock. I thought the smaller diameter but same thickness would suffice, but I'm going to stick with the advice here and find something beefier. I'll shoot Nova an email and see when they expect to have more.

    I'll check out thicker seatstays, maybe even try tackling bending my own? I have access to lots of woodworking tools, so creating a jig and bending them does sound kind of fun- as long as I don't destroy too many in the process! :O

    Unsagged is easier for me to wrap my head around as well.

  12. #12
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    Quote Originally Posted by BungedUP View Post
    you appear to be well on the way to making an excellent bike. Good work!
    Thanks for the encouragement- I hope you're right!

  13. #13
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    TIG practice!

    So I have the notcher pretty much running well, the only thing that is difficult is getting the height dialed in perfectly. The tubing I'm using for practice at the moment is a downtube off of an old GT Timberline, which claims to be chromolly on the ST badge. Thickness measures at about .030", probably from all the sanding to remove the paint. I'm cleaning it up until it's shiny with emery cloth, then filing the burrs off of the inside, cleaning the cut up slightly with a file, and knocking down the paper-thin outside edges of the cut until they appear to be "normal" thickness. 15CFH argon, with a gas lens, 1/16 tungsten (purple-shop didn't sell thoriated anymore) on an older miller syncrowave (250?), set at around 40 amps.
    First time frame build, with CAD drawing! Would love feedback-weld3.jpg

    I'm having a bit of trouble with my puddle wandering on me, and have checked that I have enough argon, and I thought the metal was plenty clean. The other tip was to make sure the machine is on DCEN, which it is. Is there anything else that could cause this?
    First time frame build, with CAD drawing! Would love feedback-weld1.jpg
    As far as penetration, I know the picture isn't great, but does it seem reasonable?
    First time frame build, with CAD drawing! Would love feedback-weld2.jpg

  14. #14
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    Looks way hot for my taste. I purge, but...


  15. #15
    The cat's name is jake
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    Does your Sync 250 have a pulser? If so, use it. If it does not, I would manually pulse with the footpedal. When pulsing, you will need to set your machine to a substantially higher amperage - how much depends on how you are pulsing. My suggestion is to pulse a higher amperage, for a shorter time, rather than a lower amperage, longer time pulse (however you do it).

    You have PLENTY of penetration there, but you are really cooking your material. Part of that is exacerbated by the short tubing sections, as they have less head sinking capability. Again, my suggestion is to work quickly, rather than slowly. Welding faster often requires more amps, but in the end, the heat input is drastically lower. All that just comes with time and practice, but knowing that moving quickly is preferred over moving slowly might be able to help you out some.

    Try this - If you don't have a pulser, start by running your machine at 85 amps or so. Make your fishmouth cuts, but don't file them back much - you can file the ears back a little where they get really thin, but don't go until they are exactly the same thickness as the rest of the tube. Tack your little practice piece, then start welding by pushing the pedal all the way down quickly, filling the puddle, then backing off to as little as you can without dropping the arc. Then repeat the process, trying to make the second puddle the same size as the first. initially, shoot for doing this around 1 pulse per second. Maybe find some classical music on You Tube at that speed. Practice that for 10 sets or so. You may need to fiddle your amperage on your machine to do this. The idea is that the bead opens up to the correct size (about 3mm or so) at full on, and then you back off to next to nothing as soon as it's the correct width. It will require the most amperage when the joint is closest to 90 degrees. As it backs off to 0 degrees, you will need to either have the pulse on for a shorter time, or not put the pedal fully down. If that doesn't help you any, let me know and there might be some other strategies to try.

    For scrap, consider just purchasing tubing from your local steelyard, or from Aircraft Spruce/Wicks. I'm sure there are lots of us around here that have scrap we could send your way as well. Dealing with old paint is crummy business, in my opinion.

  16. #16
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    TIG round 2!

    BungedUP,
    My machine does not have a pulser- I wish it did! Thank you for the suggestion! I definitely don't have it dialed yet, but the pulsing with my foot is a cool trick. It just clicked in my head the way you mention it. I've had to weld not-so-good fit up with the MIGwelder, and I essentially do the same thing, and I actually like how it makes the weld look better than the regular old MIG weld.
    So anyway, I went and fit up some more joints with less taken off of the ears:
    First time frame build, with CAD drawing! Would love feedback-weld6.jpg
    My first try was too hot, or so it seemed as I was welding, so I turned the amperage down incrementally to about 50. In this picture you can see my previous welds, next to my first try at pulsing, which looks like it overheated less. Penetration is still looking excessive too.
    First time frame build, with CAD drawing! Would love feedback-weld4.jpg
    Next joint I tried even lower amperage at first, then realized I was compensating by turning it down, not speeding up. So at the very end of my time, I had a good little run of going way faster than I usually do, with amperage at about 60. However, I think I already had cooked the piece by that point.
    First time frame build, with CAD drawing! Would love feedback-weld5.jpg
    I feel like the pulsing is helping, because the shoulder and ripples seem a little more consistent. It also gives me a bit of a rhythm to follow, which really helps when me when I weld. I'm excited to get back and do more!
    Thanks again for the tip, I contacted Walt about some scrap, and will see about buying some fresh tubing locally.

  17. #17
    The cat's name is jake
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    Dudeman,

    Try spacing your puddles out a little bit. Below is an example of what you might try to shoot for spacing wise. You want to make sure that your new puddle covers the previous puddle's crater, by 25% or so. Sometimes I'll stack closer together, but when learning, it's tough to space things out, and do so evenly. The tendency is to stack puddles closely, and move too slowly, which in turn burns the meat! It's just down to practice really, but I think we can get some improvement to the point that you'll be happy, without too much additional effort.

    The pulse action should be quick - like a pedal stab, not so much a foot rock. Imagine that you are Neil Peart or John Bonham playing the bass drum. It might be a tough job to get that down in the beginning - just do the best you can that way. Think "HEAT - mooooovvvvve, HEAT - mooooovvvvveee".

    -Peter

    First time frame build, with CAD drawing! Would love feedback-puddle-spacing-example-1.jpg

  18. #18
    The cat's name is jake
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    Also, what size filler rod are you using? I'd recommend .045" rod.

  19. #19
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    Quote Originally Posted by BungedUP View Post
    Also, what size filler rod are you using? I'd recommend .045" rod.
    I'm using 1/8" er70s- but just ordered 1 lb of mostly .045" weldmold 880 from Walt.
    I had one other question- as I was pulsing, I had the torch go out completely a number of times. Is there anything bad about that? It was easy enough to start back up, but I don't want it to mess things up.
    I'll try moving further between each pulse in the morning. Your weld is amazing! I printed it off for motivation and something to aspire to.
    Love the John Bonham visual too! I'll try stabbing the pedal- I was definitely just rocking the pedal back and forth.

    -Scott

  20. #20
    The cat's name is jake
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    Hi Scott,

    FYI - the Weldmold 880T is, according to Weldmold themselves, 312 MIG wire that they straighten and cut. A coworker and I have been working through some filler rod issues, and received some samples from Weldmold. I found that it does some things VERY well. Particularly, it is very good at filling in areas that tend to be undercut otherwise. It also is a little easier to control than 309L when welding 17-4 or 316 stainless to 4130 type steels. However, I am not quite as hot on it for general purpose welding, though it does ok. It lays flat in the middle of the puddle, but it stands proud at the toes of the weld in many cases, which I don't particularly like. It is a very small amount, and is most likely not an issue for most people. I may change my mind over time with it, but currently, I prefer a good quality (Korean) ER70S-2, and ER70S-6 for welding appearance. Either rod in most cases is entirely sufficient for the joint designs of bicycle frames, though the "880T" theoretically has the higher yield.

    I'd try to keep the torch from going out, if you can. Your goal isn't to completely freeze the puddle - You don't want to stack one cold puddle on top of another cold puddle. You want to stack one puddle on top of a cooling puddle, which is most likely largely frozen, but not entirely. It's like the puddle is a jelly filled donut - the jelly is the wet part of the puddle.

    What I do really isn't all that amazing - it's just a lot of experience. Most people are capable of that, given time. I've spent a lot of time doing what I do - the amazing stuff is when people like you wade into this for the first time, and come out with something awesome. THAT to me, is where magic happens.

  21. #21
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    Mini update: work got in the way, but did get a little practice in on the manual pulsing. No real improvement, since learning to move so far between craters is hard! the welds i did today were worse looking than last time, so i need more practice time I think.

    One weld question: I'm noticing some white smoke looking stuff on the inside of the tubes when I'm done welding- what could that be? These are fresh new 4130 tubes, hit with 240 sandpaper on the outside, simple green and rinse inside and out.

    Also need to get back to the CAD modifications and will update once I have em.

  22. #22
    RCP Fabrication
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    My inside of the tube cleaner/post ream polisher.


  23. #23
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    Ha...

    Did the same thing to polish the tapers in my lathe/mill spindles, albeit a bit less artfully, perhaps. I used an old broom handle. A flex hone is nice, particularly if you want to remove a bit more material.
    Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
    - John Hajny, a.k.a. TrailMaker

  24. #24
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    Quote Originally Posted by RCP FAB View Post
    My inside of the tube cleaner/post ream polisher.

    Thanks! I'm going to see what I can cobble together today. Do you focus on the few inches by the joint, or do you do the whole inside? Also, do you get it where it's shiny like the outside of the metal?

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    I usually just clean the ends to bright metal. Then I clean the rest with alcohol.

  26. #26
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    Tubing blocks are done, and got my wheels so I can figure out the rear end clearance, Clarence.

    Re-downtube: Is strength a huge issue with the way I have it set up and my riding style, weight, etc? I'm having trouble a.) locating a replacement tube with a bend that will work, or b.) designing the way I want the geometry around a straight tube. Would a headtube gusset help or am I way off base and really need a beefier front end?

  27. #27
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    More TIG/ Tubing blocks/ inside tube sander thing

    So I got to spend most of today gathering things, and building things and welding to work towards building my frame. It's been a really fun way to spend my free time! Anyway, I got some scraps and .045" weldmold rod in the mail from Walt today (thanks!) and went right to work.
    My mitering jig on the lathe I "thought" was dialed in, but it seems to have too much flex in it, and unless I take over 10 minutes per miter it pings and makes bad noises. So I'm going to try a slight redesign and see what happens. I think it's cantilevered too far away from where the quickchange toolrest attaches, so I'm going to try to get it more centered. Also, I have to figure out how I'm going to get accurate angles. I thought the compound toolrest would work, but when I dialed in a 40* cut to test it tonight, it came out to 50*, which I believe is because the offset from the rotation point of the compound toolrest. I guess I could try the mill, but I don't really want to angle the head for each miter?

    So the tubing blocks are so helpful, things aren't falling out of the vice when I try to file. Great idea from this forum!
    First time frame build, with CAD drawing! Would love feedback-blocks.jpg

    Rtcfab- thanks for the idea on cleaning the inside of the tubes- it works great! Trailmaker's broom handle idea inspired my "creation" I'm using 80 grit at the moment which seems a little aggressive, but at least it's clean!
    First time frame build, with CAD drawing! Would love feedback-sander.jpg

    So next was welding some joints together, to what I believe was headtube material. Seemed like a good opportunity to try thicker to thinner metal. I also kept working on the pulsing, which in a couple awesome moments, I feel like I had it. Then promptly burned holes or contaminated my tungsten, or melted off the end of the headtube... The penetration is looking much more acceptable, and I think the thicker headtube could have helped that. Do you guys think the welds are cold enough, or do I need to go faster? I think going to the .045" rod really helped. It seemed like I didn't have to keep the heat up as much when I dabbed the filler material in.
    These are the two sides of the same joints. Any feedback is greatly appreciated!
    I gotta say, I was pretty psyched to see my first shiny looking weld!

    First time frame build, with CAD drawing! Would love feedback-weld7.2.jpg
    First time frame build, with CAD drawing! Would love feedback-weld7.jpg

  28. #28
    The cat's name is jake
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    I'd say you are making some improvements. Keep practicing - I personally think in the beginning, you are better off welding for an hour, then not welding anymore until the next day. If you do that regularly for awhile, you show more gain than say, welding 8 hours straight (keyword is "regular"). There is something in letting your brain process what you did overnight that I think is more helpful than just strict number of hours total.

    Can you take a picture of the tube coping setup that you have? Maybe someone can help get the setup sorted out from the picture.

    P.s. Nice looking tube blocks!

  29. #29
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    Great looking tubing blocks, the grey sections look a bit hot. The shiny parts are better.
    Keep up the practice. Without a heat sink it may be a good idea to weld a section and then turn the piece over and weld on the other side. Your HAZ look kind of wide and that would probably help. I started using this cheap HF piece as a heat sink until I made and bought my own.
    Tail Pipe Expander
    It's better than nothing and helps control the heat.
    take off the rubber bands and maybe use some wire loosely applied to hold it together when you take it out.
    Here's a not so perfect weld:
    Name:  11505646893_10a58df4f3_m.jpg
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    If you notice, it's a little hot on both tubes at the 3 o'clock portion if the top is 12:00, but the HAZ is a bit smaller. This is because that part of the joint is a lap joint and the 12 and 6 is a butt joint. I needed to let off the heat there and will try for better next time.
    140amps 30% on time 15% background pulse 1.8pps
    cheers
    andy walker
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  30. #30
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    Hey;

    Definite improvement in the welds. This coming from someone who knows what they should look like... not like mine. Nice tube blocks! I would think it would be very problematic to miter on most lathes, which I assume are old and variously tired. Rigidity is very difficult to achieve with so many interfaces. Speeds & feeds are tricky on tubing as well no matter how it is done. You might investigate using your mill, something like this.
    Attached Thumbnails Attached Thumbnails First time frame build, with CAD drawing! Would love feedback-crownarmmiter1.jpg  

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    And maybe try lapping the hole saw and the teeth also,
    pic from pvd,

    so the saw sits flush and true, and flip it around to either file the teeth or lap them without breaking them. I carefully file with it in the lathe so it doesn't grab the file. You might notice less pinging and grabbing.
    cheers
    andy walker

  32. #32
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    That tube cleaner idea is awesome!

    Those are head tube scraps, yes. I try to make sure I send a few head tube chunks to everyone who wants scrap because they are good simulations for actual bike joints (and they can double as fake BB shells for practice too).

    -Walt
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  33. #33
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    So you put it in the chuck and file the teeth as its turning? I tried touching mine up a bit with it stationary (seems like these makita hole saws are all high at the welded seam)

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    I have used lenox hole saws for a few years now. They are a little bit more than the run of the mill ones, but I pull them out of the box, toss them on the arbors and miter tubes. Never had one that didn't work just fine out of the box.

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    Yep, they have a bit of a bite and that takes the edge off and is cheaper than real annular cutters like Strawberry's. Lennox may work out of the box, but it doesn't hurt to true it up. Until Whit jumps into the conversation, I'll share his pic of the hole saw prep work:
    First time frame build, with CAD drawing! Would love feedback-facingholesawbutt.jpg
    turn it around and just lightly touch off the edges with a file carefully so you hold the file such that if it kicks back it goes away from your hand. The handle away from you.
    cheers
    andy walker

  36. #36
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    Quote Originally Posted by afwalker View Post
    Great looking tubing blocks, the grey sections look a bit hot. The shiny parts are better.
    Keep up the practice. Without a heat sink it may be a good idea to weld a section and then turn the piece over and weld on the other side. Your HAZ look kind of wide and that would probably help. I started using this cheap HF piece as a heat sink until I made and bought my own.
    Tail Pipe Expander
    It's better than nothing and helps control the heat.
    take off the rubber bands and maybe use some wire loosely applied to hold it together when you take it out.
    Here's a not so perfect weld:
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    If you notice, it's a little hot on both tubes at the 3 o'clock portion if the top is 12:00, but the HAZ is a bit smaller. This is because that part of the joint is a lap joint and the 12 and 6 is a butt joint. I needed to let off the heat there and will try for better next time.
    140amps 30% on time 15% background pulse 1.8pps
    cheers
    andy walker
    Flickr: afwalker's Photostream
    Walker Bicycle Company | | Walker Bicycle Company
    Thanks for the tip- there's a HF not too far from here, I'll check out the tailpipe deal.

  37. #37
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    Notcher shenanigans/ more TIG practice

    So here is a picture of my original setup for notching tubing. It was made using the materials available to me, and I machined the lower clamping surface so it is parallel to the angle iron for holding the tube.
    First time frame build, with CAD drawing! Would love feedback-lathe1.jpg

    I figured getting rid of one potential area for flex, the quickchange tool holder would be a good start, so I swapped back to the original (turret style?). I also locked the crossfeed while cutting, since I had only locked the compound toolrest previously. Finally, I got rid of the stupid milwakee cutter, and found these cheap ones at the hardware store, made in the USA, with the arbor built in. Not sure if they'll give me enough length for smaller angles, but so far with these tweaks it cuts much better. Still slow, but no popping and pinging. Also tested a 70* angle cut, and checking with a digital angle guage came out perfect, so I'm pretty excited about that!
    First time frame build, with CAD drawing! Would love feedback-lathe2.jpg
    The headtube joints I was welding measure somewhere between a 1-3/8" and 1-1/2" O.D., so I used the 1-3/8 cutter and used a 10" file to make the joint fit better. I figured a little practice with perfecting joints with a file will come in handy!

    Tonight's welding pictured is both sides of the same joints. I have some areas I'm happy with, and the fact that I didn't burn any holes or melt the end off of the headtube is good, but overall heat input seems the same, maybe more in places. It seems like the underside of the DT takes a lot of filler; I thought it went great, but it looks a little undercut in hindsight.
    Which brings me to my current dilemma- sometimes when I try speeding up I'm not able to feed enough filler into the puddle to keep it from getting all flat and overheated.
    I think it's probably mostly just need more practice. Gonna shoot for roughly an hour a day throughout this week.
    First time frame build, with CAD drawing! Would love feedback-weld8.jpg
    First time frame build, with CAD drawing! Would love feedback-weld8-1.jpg
    Thanks everyone for the props on the tubing blocks- it was fun to do something that would help, but was a little easier

    I'm learning a lot- thank you guys for all of your input!
    Scott

  38. #38
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    Just for clarification - the oxide coloring that you see near a weld is not the same as the HAZ. It's very commonly misidentified as such. The HAZ corresponds with changes in grain structure of the base metal, due to heat. The coloring you see on the metal from welding is where oxides are forming on the surface at fairly low temperatures - from around 400-650 degrees F.

    Think about it this way - the effects of a HAZ are a time/temperature dependent reaction. The colors on the surface of the metal can be dramatically altered by shielding. This does not change the time / temperature aspects, but does change the temperature when the metal is once again in contact with oxygen, which is when the oxides start forming again. The surface oxidation color band is not the same thing as the HAZ.

    With a properly prepped and shielded setup, you can make a puddle, not move the torch, cut the arc, and you should end up without any oxide coloring if you leave the torch in place with a few seconds of post flow. Even though there is no discoloration, there is still a HAZ. You just can't see it, because it's structural change in the metal.

    Sorry for the disruption - carry on!

  39. #39
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    Regarding the popping and pinging - I almost guarantee that a substantial portion of that is the fault of the hole saw. Some of the other suggestions about truing the back of the holesaw by turning them in the lathe are good - it does indeed help.

    The #1 holesaw you are after is the Starrett 6-pitch hole saw. You can order them up from MSC, and they will be at your door in a matter of a few days. The next in line are Morse and lenox holesaws, but really, try to get the Starret ones. If you true one of those up, they will cut very well, for an amazingly long time. Additionally, they can be resharpened with a careful hand at the grinder, regrinding each tooth (unless the teeth are broken off). I'd be willing to bet that with the 6-pitch holesaw, you wouldn't detect much difference between the QCTP and the 4-position turret toolpost.

    RPM should be in the neighborhood of 300 rpm for typical bike related holesaw sizes. I wouldn't go much above 350 rpm - go lower rather than higher for these.

  40. #40
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    Quote Originally Posted by BungedUP View Post
    Regarding the popping and pinging - I almost guarantee that a substantial portion of that is the fault of the hole saw. Some of the other suggestions about truing the back of the holesaw by turning them in the lathe are good - it does indeed help.

    The #1 holesaw you are after is the Starrett 6-pitch hole saw. You can order them up from MSC, and they will be at your door in a matter of a few days. The next in line are Morse and lenox holesaws, but really, try to get the Starret ones. If you true one of those up, they will cut very well, for an amazingly long time. Additionally, they can be resharpened with a careful hand at the grinder, regrinding each tooth (unless the teeth are broken off). I'd be willing to bet that with the 6-pitch holesaw, you wouldn't detect much difference between the QCTP and the 4-position turret toolpost.

    RPM should be in the neighborhood of 300 rpm for typical bike related holesaw sizes. I wouldn't go much above 350 rpm - go lower rather than higher for these.
    I ordered the three main sizes of Starrett hole saws that I'll need today- thanks for the tip! I'll face the back of them when they get here. I also had my spindle rpm down to about 90. Bumped it up for todays cuts to around 250 and it seemed to cut just as well, but I was able to feed the tube through quicker.

  41. #41
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    Quote Originally Posted by TrailMaker View Post
    Hey;

    Definite improvement in the welds. This coming from someone who knows what they should look like... not like mine. Nice tube blocks! I would think it would be very problematic to miter on most lathes, which I assume are old and variously tired. Rigidity is very difficult to achieve with so many interfaces. Speeds & feeds are tricky on tubing as well no matter how it is done. You might investigate using your mill, something like this.
    I like that idea, but don't think I can afford a vice like that. Seems like I'm getting the kinks ironed out of my lathe setup, but this is definitely a possibility; or just doing it with a hacksaw and file if I have to!

  42. #42
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    More TIG

    With the hole saw setup working decently, I was able to semi-quickly prep my joints for tonight (and the fact that one of the "notches" was already cut from this scrap by Walt). I moved where I'm welding to a higher, more comfortable table which was a nice change.

    I almost feel like I've taken a step back, but I'm not sure. No holes in the welds, but I did weld my tungsten to the metal for my first time ever.
    I was having trouble with my Tungsten becoming contaminated when I don't think I had actually hit anything.
    I've been clipping the end of my filler each time I start up again (since I have the bad habit of removing it from the argon immediately). Argon is at 15 cfh, and things are cleaned to bright metal inside and out. Sprayed with simple green, scrubbed then rinsed and dried really well. I really have no clue what is causing it. Any ideas? The only thing I can guess is that I'm closer to the puddle than I think.

    I really need to practice keeping my torch angle aligned with where I'm at on the tube. I kept melting off globs of welding rod inadvertently which kinda ruins my whole flow. I believe this is BB material welded to .035 (angled tube) and some sort of very thin butted material through the pierced hole. Not super proud of these guys, but maybe I can learn something from them:
    First time frame build, with CAD drawing! Would love feedback-weld9-2.jpg
    First time frame build, with CAD drawing! Would love feedback-weld9.jpg
    First time frame build, with CAD drawing! Would love feedback-weld9-1.jpg

  43. #43
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    Hey;

    Your first time dipping the electrode? I'd almost call you a liar on that one. That's usually the first thing anyone fuses to a tube! Yes, the filler can jump to the electrode if you get an amperage spike, hit an irregular spot, waver in your position, dip at the wrong time, or just get too close. I find that I cannot weld very much at all without having myself braced against the work, and that makes it very difficult. The hardest part from my perspective is being able to roll with the contour of the joint as you weld. Any movement on my part and I lose my distance from the work and my weld wanders.

    Practice...

    Understand that - in the extreme - all that fancy welding Peter and others can do does make a variously theoretical if not practical difference, but what you are doing now will glue a bike together, and it will probably hold and last to a reasonable degree. Yes, good welding is more structurally viable in the extreme, and overall will be more reliable and long lived, but at a certain point just becomes eye candy and a point of pride for the craftsman. For the rest of we schlubs, well, thankfully, you can make a bike without it. Don't get too hung up on it and let it get in the way of building your bike!
    Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
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  44. #44
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    Quote Originally Posted by thedudeman View Post
    I also had my spindle rpm down to about 90. Bumped it up for todays cuts to around 250 and it seemed to cut just as well, but I was able to feed the tube through quicker.
    At least with a belt drive machine going to higher RPMs means lower torque, which might reduce the tendency of the cutter to dig in and snag. You'll have to feed slower to keep the MRR in the same range.

  45. #45
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    Oh I've contaminated my fair share of tungsten from hitting the puddle! Hahaha, this is just the first time I had to undo the collet, pull my torch off, then break the tungsten off my metal.
    I didn't know filler could get on the electrode from amperage spikes or irregularities...

    Thanks for the encouragement- I'm going to still try and hit my goal of an hour a day for the rest of the week and see what happens. Looks like the starrett hole saws will be here tonight- that was sure fast!

  46. #46
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    I don't know about the starrets but the lenox (better than starrets IMO) come in 1-7/16" for perfect head miters. Also 1-3/16" for ex butted seat tubes.

  47. #47
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    Hey;

    I've had one bad experience with the new design Lenox hole saws. They've changed the design of the slots in the side, hyping them as easier to dig the discs out of or something. I've worn out dozens of the old style straight slot ones, but the FIRST TIME I used one of the new ones, the edge of the angled slot threaded itself onto the edge of the part I was holing and mangled the hole saw, within 10 seconds of hitting the trigger. Pissed me right off. The new design is an answer to a question I was not asking. Your results may vary, but I'm not impressed.
    Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
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    Could have been a bad one with a lip on the edge of the slot or something. I've literally used 250-300 of the new style ones over the years with no real issues.

  49. #49
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    thedudeman - don't worry one bit about going backwards. It's not really going to happen if you regularly practice. As much as humanly possible, take the desire for what you want it to look like, vs. what it does look like out of the equation. Sometimes it gets better, sometimes it appears to get worse. The big picture though is that practice = overall improvement. It is what it is, and it WILL get better with practice. Don't sweat what happened tonight, vs what happened last night. Try to just enjoy doing it (which you very well may be).

    Much of the process of improvement happens at a subconscious level. Initially, most of the improvement will just happen, and you won't understand why it gets better (you may not even be able to tell what you are doing now that you weren't doing before).

    John is right as well, that what you are doing now will hold a frame together.

    -Peter

  50. #50
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    Ok, so I'm looking at some of your pictures, and trying to figure out anything that might help you.

    Your base metal is overheating in part due to it's small size. Small chunks are going to heat up quickly, and then can continue oxidizing long after your shielding gas is removed. These oxides can interfere with welding, and stainless fillers are more difficult to control once this happens. I wonder if I'm seeing a little of that in your weld bead. In order to try and wet out a stainless filler on an oxidized metal surface, you need more amperage. Thus, you either don't get the puddle profile you want (poor wetting out), or you put more amps down and all of a sudden the puddle opens up and now you are looking at Lake Superior! 312 or 880T isn't as bad as some that way - it's better than 309L in that regard, but your regular old ER70S# doesn't behave that way. Once you get closer to welding your frame, you could switch back to the 880T if you were wanting to use that.

    You might try .045" ER70S-2 or 6 filler, and see if things get a little easier. The bead won't be as shiny, but you may have a more consistent shaped bead. Once you get closer to welding your frame, you could switch back to the 880T if you were wanting to use that. Alternatively, you might keep the total temperature of your work down by giving it time to return to ambient temps, or cleaning the oxides off with a brush or some such. You could also come up with a heat sink of some sort.

    Just a few thoughts, but don't think about them too much.

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