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Guypie

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  1. And it came out like this. fairly yuck after heaps of fileing/sanding/scotch bright it looked a bit like this: Its kind of ok, but I'm not really happy with it. So with about a days worth of work in it I decided to scrap it and start again. Today I spent most of the day turning these out of some mystery steel from my box of offcuts: They look a bit like oldschool skateboard wheels. Much more happy with the outcome, I need to cut the shroud parts down to the correct size so I will probably go get a nice new file tomorrow and just do it by hand. I had a little test run on the lathe putting it off centre with the 4 jaw chuck. It would work but it was mildly terrifying, not to mention if the jaws slipped on the workpiece it could turn it to scrap metal real quick
  2. After a few hours of work (not even kidding, gotta go real gentle on the old girl!) I came out with these: I used a piece of stainless tubing I had to make the shroud part and tacked it on then remembered that stainless is poos and will go all sugary on the backside if it gets too hot as below. So I filed off the tacks for round 2 This time with 4130 tube: Then I welded it up...
  3. Aaaaaand welded in place: Will need to send a reamer down the tube as internally it has gone kind of hourglass shaped from welding it in place. I threw the frame back in the jig to see how far/close it was to original dimension, its pretty darn good! Using the height gauge it looks like in relation to the headtube the seat tube about 0.5mm off line. Which I don't think will be noticeable at all in the end product. I gave the lathe a cleanup at this point as the swarf overflow was starting to get sucked into the leadscrews which is generally a bad time This is my old lathe, its a selson probably from the 1920s. The headstock bearings are absolutely stuffed and it can only turn anything by virtue of being heavy. Too much cutting load and it starts to vibrate like crazy as the spindle "rolls in the slop" if that makes sense. I actually have another newer much better lathe on the other side fo the workshop, but it needs 3 phase that I don't currently have. To make the dropouts my plan was to turn some centres for the axle and weld them into a bit of tube, then cope the chain stays and seat stays to weld to the dropouts. kind of like this: but a bit more simplistic. So I got a chunk of stainless and started whittling it down...
  4. More pics of welds: These are the uglier ones: I think the one sied of the BB wasn't clean or still had paint residue in the steel cause it was a bit fizzy and I couldnt really do much about it. I popped it on the scales to see how things are tracking: 1556g, not too bad. I think it will come out around 2.7kg mark, I have been making the "dropouts" (thru axle so they dont drop anything out) and they are going to be a bit heavy hahaha. I turned a reducer out of stainless on the lathe, which took a long time because my lathe is very worn out. A heck of a lot better than no lathe though! In the frame: This actually added 10% to the weight of the frame so far haha. I don't really care about the final weight that much, but I think it is worth considering while I am making bits and pieces for the frame.
  5. Front triangle is now fully welded, a few rough patches as you would expect for a noob but on the whole I am pretty happy and fairly confident that if will hold together fine I turned up some heatsinks out of scrap ali I had laying around to try minimise distortion: Some of the welds: The heatsinks probably helped, but the headtube has ovalised a bit. I will probably just give it a bit of a squeeze to get it close and see how it goes.
  6. Some shots of the fitup: And tacked it in place. Current toll on the jig: 2 plastic parts melted haha. though they did their job, and 1 is still useable. As a single use jig I still think its pretty good. Probably should have gotten a bunch more done today, but ended up getting carried away on my morning bike ride and did 20km/700m vert up Pirongia mtb trails and was pretty tired after that!
  7. I had heard about the brake cleaner thing, pretty scary really. I figured out most of my problems with getting nice welds had more to do with sheilding. I'm pretty sure my torch body in just old and worn out. It has a gas tap on it that didn't have an o ring so I put one in, the wrapped it with electrical tape. I have borrowed a gas lens off a friend and that seems to help too and has brought down my gas flow requirement which is nice. I have a new torch body and gas lens setup on the way from aliexpress. After coping some of the tubes I had a couple of offcuts left so I had a little test on those with the gas lens setup: Happy with that. By this time I had already tacked the seat tube to the BB, so I just went ahead and welded that up. you can see it in the background of the above picture kind of, its not quite as good as my test weld as its a bit tricky with the BB being 3mm and the tube 0.9mm trying to get the heat to go where you want it. Heres a few shots of the tubes getting added to the jig: On the picture below you can see a little block that I 3d printed to get a level surface to reference so I could accurately clock the tube 90 degrees for the bottom bracket cope, also fresh deliverys from @ThePog thanks!: A few more pics to come in the next post...
  8. That is awesome! I will have to make one of those once I have finished on this bike
  9. PM'd about the lengths. Good to know that quality will do the job! I figured with the remaining tube I have I would make a tiny bike. So made a 1:5 scale version of the frame hahaha Started welding it together and had all of the contamination problems. I have been cleaning the metal with alcohol, I think it might not be aggressive enough so I figured I would call it quits for the day and try again later with some acetone. I have probably hit my learning absorption limit for the day as well. go to sleep and try again tomorrow.
  10. Here is the failed weld: While it certainly isnt going to win any beauty contests I think as a bike frame component that weld wouldn't fail, it took a lot of beating on to get it to crack. I coped and welded a few more joints and that's where I am up to now, I think there must be pockets of galve causing issues with the weld as I am getting little pockets of contamination even though everything looks nice and clean: ' I am probably going to do a few more practice copes and welds and then just go for it. I figure this is bike frame no.1, may as well just get it done and consider it to be a learning process and not a final product.
  11. Progress update: No further work on the frame But a lot has been happening working towards the frame build. I turned up an arbor for a 1" holesaw and welded the holesaw to the arbor as @Valiant suggested and got some 1" mild steel tube 1.2mm thick to practice welding on. It is galve which is somewhat annoying, so I ended up plugging the end and filling it with acetic acid to clean all the galve off the inside. I filed and sanded the galve off the outside, though I think there may still be tiny specs or pockets of galve hiding in the dips and divots of the surface as I am having a bit of difficulty with porosity occasionally in the weld. I also upgraded my coping jig as the hose clamps just weren't cutting the mustard. A couple of g clamps welded to a second piece of angle iron now clamp the tube: I lined the jaws in skateboard grip tape for maximum traction as if the tube slips it snaps the teeth off the holesaw which is super annoying. It works great. I might chop off the t bars and turn some thumb screws with a nut on the back to make it quicker to open and close when its mounted on the lathe later, but for now its good to go. This is my first practice piece: I thought burning through was going to be much more of an issue but it was not a problem. I found around 55a seemed to work best, the difficulty is getting comfortable and moving the torch in an arc so you don't end up balling your filler before you get to dip it in the puddle. I took that join over to the anvil and squashed it flat, it held together well: So I whacked it backwards and forwards until it failed. It took a lot, more than what I was expecting considering it wasn't a very pretty weld!
  12. I did wonder about tig brazing. I did a bit of googling and found a bunch of people who said it cant be done blah blah blah, but I found the same thing when I googled about mig welding a bike frame. Then there was one thread where a dude actually did it and it was fine. He even posted up a update a few years later and said it was still all good, no cracks or failures. It was a trials frame too so not something that would not have been nana'd either Edit: just had a look, er70s-2 is the recommended filler for 4130, its rated 483mpa tensile, the silicon bronze is 340mpa. Does that mean if the fillet is say 20% larger strength would be same same? Maybe we should make a few test pieces and smack em around with a hammer...
  13. Oh yeah, I forgot to mention that. The jig parts are 3d printed. Means I can sit by the fire inside while I "make" a thing in the shed hahaha. I am thinking it will probably be a single use jig, we will have to see how they come out after the frame has been in and out a few times.
  14. I have a tig, though I have a few hurdles to get over with it before getting on to welding the frame. First of all I am not very good at it, so practice is needed. Second, I don't have a pedal, a pulse function or downslope on my welder. I think if I can get a pedal sorted it will do the trick, it can take one but it is a very old cigweld with a 7 pin connector and I have not been able to find a pinout for it.
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