Bicycle Frame Build 08 - Bending Chainstays
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- čas přidán 13. 01. 2015
- Video 08 in the Beginner Build Bicycle Frame Series. If you ever wondered how to build a bicycle frame this is the place.
I finally get around to bending the chainstays in my homemade tube press.
#diy #bicycleframe #fixedgear #singlespeed #welding #machining #chainstays
Music:
Backed Vibes Clean - Kevin MacLeod (incompetech.com)
Life of Riley - Kevin MacLeod (incompetech.com)
Licensed under Creative Commons: By Attribution 3.0
creativecommons.org/licenses/b...
For what it's worth, its nice to experiment. Allows everyone to observe how the tubes gonna react. Great post dude.
Thanks man!
Another good way to make a clean bend without flattening is to cut a few slits half way into the pipe in a few evenly spaced positions along the bend. Then weld them over to fill them and grind/sand smooth after bending. This works especially well with sharp bends.
Amazing videos. Love it! Thanks for the great work.
There is a ratio of dish soap and water that is frozen for bending precision brass tubing for musical instruments. To find the ratio you will have to experiment. Instrument builders keep their mix a secret.
I like mixing cool aid in the mixture. When it melts, I can drink it. Kidding! I've since come to realize that I need to invest in a real bender :) My frozen water shenanigans are over!
More thrilling than Netflix commercials series 😂🤪😀😃
Great idea filling the tubes with ice. Will probably save me from the same mistake. I thought of filling the tubes with cement mix ( powder only, not the gravel & sand mixture ) and taping off the ends with duck tape. Never tried it though. Both methods might work. Only downside I can see for the ice method would be the low temp. Might make it harder to bend. I suppose with the cement powder method, the tubes could be heated a bit to make them bend easier. Some day maybe I'll test this method.
Maybe fill with sand can work to, a fine sand.
Apparently, adding soap to the water before freezing makes the resulting ice more flexible.
nice!
I'm interested to know why you used wood for one half of the form and V-blocks on the other half.
Wow, a roller bender is what you needed. And its a far more simple thing to build.
But aren't roller bender for larger raidus bends? And these chainstay tubes are not round, they're oval shape. Don't get me wrong thoough, I'd love to own a roller bender! ;)
@@PithyBikes Not at all. If the curve is consistent, then it would work nicely.
For a beginner, do you recommend frame building using Steel or Aluminum tubes ?
Also, what is the material for the frame tube material used in the video , & thickness?
I use sand but water is a f....g great idea!!!!!!!!!!!!!!!!!!!!!
you can use compacted sand
+Colin Riley yes, thanks! I need to get a real bender. Some day I'll do a video on that. :)
fill the tube with salt with the ends plugged, bend then and rinse out. it works good
I've heard of sand but not salt. Interesting! Could be good because salt can dilute.
A fine sand. I think it works.
I agree that the angular notch on the form contributes to the problem. My impression is that you don't really need a curve, though. What you want is a form that contacts the tube at a tangent that is as nearly parallel to the direction of force as possible, so only its edges. A square bottomed trench with a width slightly narrower than the tube will do. It maybe 'pinches' the tube a bit, but that force counters it kinking. This could perhaps be built up from metal (two plates separated with spacers, then a bent bar for the trench bottom) in a form that matches the taper of the chainstay tube.
+Sebastian Wiers Interesting idea. I've never seen a square channel for bending. It's been quite a while since that video so I've had lots of time to think about it. It think the best course at this stage is to simply buy one! :) What I've learned from observation is that the more form that touches the tube the better. This insures that the tubes wall have no where to go but bend in the direction you want. Thanks for watching :)
The ice technique has been used to bend brass tubing for musical instruments for many years...
Nice! I learned about his technique on MTBR forums. I think in this thread - forums.mtbr.com/frame-building/tube-bending-703950.html
Some musical instrument builders fill the tubes with melted lead while most prefer the soapy water. Obviously cleaning out the lead after the bend is made requires reheating the metal and carefully cleaning the interior of the tubing.
Clever!
Loving your journey. An idea only but laminating plywood might be good for a form and stronger. Otherwise some reprint or similar, especially f you can get some offcuts from work or similar!😀
iron or aluminium pipe?
You can use sand inside pipe and safe your time .. And thanks
mate make yourself a roller bender, more easy to do than all the work you have done., and you can bend a long section and cut as many sort parts as you need them good work .
+quickie3 Agreed, I need a better solution :) Thanks for watching.
A roll bender will not help much on a tapered chain stay. Using the V-Blocks bender isn't a horrible approach. Nice work though, problem solution building is a path to a higher level of experience. Keep on
try fill pipe with sand
green goblin Ah yes I want to try this method some day! Beats waiting for ice to freeze :)
+Pithy Bikes Dont bother . Neither really works. The best way is to use a hardwood for the former and cut a groove that nearly matches the blade but even then you get some flattening occur. I've tried capping both ends, drilling a hole in one cap and then brazing a nut around the hole then filling it with sand and then putting a bolt in the nut and tightening it down into the sand as hard as humanly possible and still flattening ocurs. Not much maybe only 1/2mm but still noticeable. I think the only way is to have a groove in the former that exactly matches the shape of the blade all the way.
+fred I totally agree. I've been thinking of ways to make a new wood die that matches the diameter of the tube. I'll prob revisit this at some point. My current hodge podge die is less than ideal.
+Pithy Bikes If you succeed Pithy please post it. It''s my life's ambition to bend a tube without the damn thing flattening!
+fred the tricky part is chainstays that are not straight guage. Mine are oval at center so most likely I'll still get some amount of flattening. No flattening.. one can always dream! :)
How are you going to get the ice out????? Cool vids bro!
So question....most TUBING benders I've seen are different than PIPE benders, which is kind like what you have here...a tubing bender pulls the tube around a form, with dies on the inside and outside, where a pipe bender simply pushes in the middle (and kinks/wrinkles the tube)...like this...did you pick this because it's not a steep bend? Or because of the irregular cross section of the tube?...I'm getting ready to start building some frames just for fun, and I'm seriously considering just a 1/2" emt tubing bender (which is actually closer to 3/4")...
Nathan Hamler Hi! A tube bender with a die on the inside is a mandrel bender. I've never seen anyone build one of these as a DIY. Yes, you're correct, you cannot mandrel bend an uneven tube like the one I have in the video that is oval shaped in the middle. And yes, that's why I bent the tube in the way I did. Partly because of cost and just to see if this simple setup could do the job. I would love however to try and build a more traditional tube bender that has the two round dies, one for the radius and the other to do the pushing on the lever bar. I think most folks get the best results with that setup. I'd love to see someone 3d print a die for an oval tube. That would be a fun thing to try!
Its cause that piece of wood (form) is too big. With typical pipe bending the "form" or the shoe is normally just smaller than the pipe you're bending cause once bent the pipe will fit into the "form" so try a smaller gap in the form with a big gap it means more room for failure
Thanks for the tip. All around my wood form is pretty terrible. It's the wrong material to begin with. I used a 2x4! Yuck!
But great work
So the 2nd attempt with the frozen chainstay was with new chainstay, right? You did not freeze the wrinkled chainstay?
yetijoeyetijoe Hi yetijoe, Yes second attempt was with a fresh new unwrinkled chainstay.
Thanks for that question - I would have misunderstood.
hey there bloke, I'm wondering what diameter tubing you're using and costs all up for it? mind letting us know?.. I wonder if an exhaust shop would mind doing some bends for ya on the cheap? might be a lazier way of doing the odd bend here or there..
+Monstah Jones The tubing is from henryjames.com. I'm bending chainstays so meybe they're too small dia for a exhaust shop :( And the part I'm bending in this case is oval so its extra tricky.
To help keep the kinks out fill the tubes with sand before u bend it and replace your aluminum push with steel/aluminum wheels u can get them in the tubing sizes then u can just change them out with different tubes and your wooden piece u can make for the different size tubes also. Later dan
+djtoo7 right on. Thanks for the tip. I've got something cooking up for a better bender. Sometime in the future I'll start a build of it.
Cool, i got one of these when on sale for like 199, it dose most everything and can't build one cheaper...
later dan
www.eastwood.com/professional-tubing-bender.html
Ok we need try whit other kind of machine.
Yup, when bending tubing, you need to sandwich the sides of the tubing tight so they don't pop out while bending along with the inner most diameter of the tube with hard tubing. Soft metal tubing is more forgiving with the sides.That's the first I heard of using ice for that, good idea.
+prancstaman i now use sand but ice is best with oval tubes.
your problem is the bending tool, as far as you bent the tube your tool are maintaining the same preasure point just in the midle of the bent. you need a rotary die to change the presure point in all of the curve other wise the material on the midle just expand upd side and contract on the base.. in only one point.
+Fernando Echeverria I agree. The oval chainstays can present a problem with rotary dies. But, a good die is still better than what I'm doing right now. :)
what plasma cutter are you using? I got one but I can't run mine like that
Hi. The video is sped up so it seems faster. It's an Everlast Power Plasma 50 - www.amazon.com/Everlast-PowerPlasma-Plasma-Cutter-Cutting/dp/B0081BEVXW
I'm running it on a:
California Air Tools CAT-4620A
What kind of tip is that? Is it specific to the everlast machine?
It's a standard tip. But I'm not supposed to be using it the way I am in the video. The torch came with a stand off attachment. But I don't use that because the cut is not precise enough for my taste. I tend to burn out a lot of tips by contacting them right to the material like you see in the video. I think there are contact tips but so far I'm too cheap.
U need too use rollers than those two pieces at the end of the press
Hi nice video,
Have you tried put same sand to inside of tube?
I link to the video from Bike forum.
Another question, what is the milling machine model? It looks small.
Hi, I haven't tried to sand method. I heard about it though. I might give that a try. It is a tiny mill! It's a Sieg X2D mini mill. Thanks for watching!
Pithy Bikes Thank you!
Super Dry You're welcome! Hey in case you want to know.. I picked it up from The Little Machine Shop. littlemachineshop.com/ Cheers.
Pithy Bikes Thank you for your information. But one Big problem is I am living in Taiwan, the shipping cost is too much. Would you builder other bike? Recently, I also want to be a frame builder. I had buy some cheap Cr-mo tube to trial and error. good luck!
how about use those sticks rods as a filler, stuff them it in the heated tube and bend them togatharr
+aezif dhom not a bad idea. But it prob wouldn't pack enough to pressure the inside of tube wall.
you can use hot working too bend it fast
Thanks for the tip! I should get a real bender.. (-﹏-。)
Fill the tube with sand.
did you anneal the tube before bending?
Alex I did not. I don't know if folks anneal bicycle tubing before bending. Do they? Any info anyone can give on this would be appreciated.
Pithy Bikes im not sure about bicycle tubing in general, but 6061 t6 aluminum is a heat treated alloy for strength, so when you try to bend it, that is the reason my it will crack and break more often than actually bend. You need to anneal the aluminum first, then do your bending while the aluminum is at its softest, and once you have completed the frame work, the aluminum should be re heat treated to bring it back to strength. heat treating usually has to be done by a qualified shop though, as it is a difficult process with aluminum.
+Alex Dollar The tubes used in the video are steel, not aluminium.
Use sea sand in pipe
why using wood to bend the pipe? is'nt that will deform because of the force?
+Jacky Lock yes, it deformed. I admit it was a bad idea ;) some day I want to build a better setup. Thanks for watching.
+Pithy Bikes you can use hotworking metodh to bend it
If you are still using this bending method, might I suggest hickory or another hardwood, and like some others have mentioned, end grain will work much better. Buy one piece of 8/4(roughly 2" thick) or 6/4 (1.5") hickory and glue them side to side with some good wood glue to get the width you need. A round die on the router might work better than the angle you have cut too. That way it will distribute the pressure more evenly. The way you have it puts the pressure on two acute points in the block, making it more likely to split because it is pressing both down(the base of the block being down) and outward to the sides of the block perpendicular to the grain. Hickory is an extremely durable wood that holds up well to pressure and shock (which is why so many tool handles are made of it) and it is reasonably cheap, especially with how little of it you will need. I'm sure you already have a good solution, but I just thought I'd offer up a few thoughts that might help for similar applications in the future. I like your self reliant approach. Keep up the good work.
+Brian Choitz Thanks for this info! I do plan on changing my bender setup some day. Cheers!
Probably could have filled the tube with sand too. Probably easier than ice,
Indeed. :)
Ok 8 yrs have past, if you decide to bend like this again then best to make a slurry with sawdust and water and will be 10 times as stronger when frozen.
fill the bar whit sand and then bend
+rommeo27 Yes.
move over hot dogs :D
Sand...not ice!!!...... Tim Paterek sorry for him....Didn´t read your book...
Haha yes, I am now a believer in sand. :)
this is stupid man...just get an actual hand tube bender with a 1" die. it'll dimple in both sides nice and evenly, no kinks. and it takes about 2 minutes to bend an s-bend chainstay. simple!
+madm3chanic Thanks for the candid and honest response. I agree with you. My DIY nature wouldn't let me but by now I've wasted so much time and money screwing up tubes. It's time to get a real bender. Thanks for watching.
seriously, with all the money you invested to make this machine, you could have bought a tube bending machine, made for this purpose and more efficient... still interesting build though.
+DELBOURG matthieu agreed! 😂
Heck, a 12-ton hydraulic tube bender with a bunch of dies costs £60 on eBay (about $75). A universal compact bender (without the tube dies--you would have to make those yourself) costs £75 (under $100) from eBay or Harbor Freight and is way more versatile than your bender.