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  1. #1
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    Finally made my first chainring

    I have been riding my Raleigh XXIX for 5 years and have wanting to make a chainring for it. I have all of the tools, but it has been hard to get around to it while keeping up with the regular jobs. I finally got one done this week. Took it for a spin this morning.

    It's a 33T to replace the one Truvativ ring that came on the bike originally.


  2. #2
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    Details, man, details. I'm all for custom ring makers. Looks heavy, though.

  3. #3
    Ride da mOOn Moderator
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    Always a +1 for cobblers...
    ...who make their own stuff!

  4. #4
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    Looks great!

    Word of advise: only make them for personal use / close friends.

  5. #5
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    Quote Originally Posted by icantdrive65 View Post
    I have been riding my Raleigh XXIX for 5 years and have wanting to make a chainring for it. I have all of the tools, but it has been hard to get around to it while keeping up with the regular jobs. I finally got one done this week. Took it for a spin this morning.

    It's a 33T to replace the one Truvativ ring that came on the bike originally.

    That's looking good right there

    Did you CNC or use a rotary table?


    Magura

  6. #6
    The need for singlespeed
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    How'd the first ride go?

  7. #7
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    I don't have a gram scale. I put it on my postal scale and it weighs somewhere between 40-50 grams. I didn't put much effort into making it light. Just wanted to try out the tooth profile. It worked fine on a quick 6-mile ride this morning.

    This one is machined out of 1/8" thick (3mm) 6061 material that I had on the shelf. I did it in two setups on my Fadal CNC mill. I ran the mounting holes, teeth and center bore in one operation and flipped it over to cut the step and ramp on the teeth on the other side. So it is very concentric: no runout. The teeth are machined to 2mm thickness. I will probably redo it with thicker teeth for the wider chain on my SS.

    What I learned so far: I need more clearance to mount the ring easily without removing the crank arm. I was barely able to get it over the spider. So cutouts are necessary.

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    If you decide to sell, please let me know. I like collecting various chainrings...

  9. #9
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    Quote Originally Posted by icantdrive65 View Post
    I don't have a gram scale. I put it on my postal scale and it weighs somewhere between 40-50 grams. I didn't put much effort into making it light. Just wanted to try out the tooth profile. It worked fine on a quick 6-mile ride this morning.

    This one is machined out of 1/8" thick (3mm) 6061 material that I had on the shelf. I did it in two setups on my Fadal CNC mill. I ran the mounting holes, teeth and center bore in one operation and flipped it over to cut the step and ramp on the teeth on the other side. So it is very concentric: no runout. The teeth are machined to 2mm thickness. I will probably redo it with thicker teeth for the wider chain on my SS.

    What I learned so far: I need more clearance to mount the ring easily without removing the crank arm. I was barely able to get it over the spider. So cutouts are necessary.
    How did you design it?


    Magura

  10. #10
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    Good for you, nice job! Are you going to have that hard anodized for wear purposes?

  11. #11
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    Quote Originally Posted by phsycle View Post
    If you decide to sell, please let me know. I like collecting various chainrings...
    I intend to get there before too long. I will not sell anything that I don't already have made. I know how that turns out. I need to get some 7075 material for strength and longevity.

    Quote Originally Posted by Mr.Magura View Post
    How did you design it?


    Magura
    Math and CAD. I used my old standby BobCAD V17. The software is 15 years old, but it's quick and efficient. For more complex stuff like fork crowns and 3D hot rod parts, I use a newer version of BobCAD.

  12. #12
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    Quote Originally Posted by ALBM View Post
    Good for you, nice job! Are you going to have that hard anodized for wear purposes?
    I will check into coatings that will hold up once I get some 7075. This piece is just a test mule to check geometry and function. I really want to see how long 6061 will last, just for fun.

  13. #13
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    Quote Originally Posted by icantdrive65 View Post
    Math and CAD. I used my old standby BobCAD V17. The software is 15 years old, but it's quick and efficient. For more complex stuff like fork crowns and 3D hot rod parts, I use a newer version of BobCAD.
    So, the hard way just like me


    Magura

  14. #14
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    Quote Originally Posted by Mr.Magura View Post
    So, the hard way just like me


    Magura
    Yeah, but I cheated in the execution. I have CNC mills. Your rotary table chainring is impressive.

    I honestly was a little lost at first, but I found some very helpful info on drawing sprockets that got me rolling.

  15. #15
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    Quote Originally Posted by icantdrive65 View Post
    Yeah, but I cheated in the execution. I have CNC mills. Your rotary table chainring is impressive.

    I honestly was a little lost at first, but I found some very helpful info on drawing sprockets that got me rolling.
    It's rotary table + file

    I'll ask my drawing guy if there is a shortcut, and post it if he has something up the sleeve.
    I couldn't make a CAD drawing if my life depended on it. He is on the other hand quite good.
    When I made mine, I just had the numbers on a Post-It. Not the way it's going to be in the future. Made like 3 or 4 that way.


    Magura

  16. #16
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    Nice job... Looks great.

    I've been talking to a friend that makes parts to see about getting some custom chainrings made. Let us know when you get around to selling these... I'd be up for buying one for my SS.

  17. #17
    one chain loop
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    Quote Originally Posted by CB2 View Post
    Looks great!

    Word of advise: only make them for personal use / close friends.
    I agree, but just in case you decide to go full production, put me on #1.
    everything sucks but my vacuum cleaner.

  18. #18
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    While the machine was set up, I ran a revised version of the bash guard I have had on my Blur.


  19. #19
    ride more
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    That looks really nice

  20. #20
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    Quote Originally Posted by icantdrive65 View Post
    While the machine was set up, I ran a revised version of the bash guard I have had on my Blur.
    ]
    Wow, I'd like one of those. Current bash guard is a porker.

  21. #21
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    This one is ridiculously light. It looks like it barely tips the scale over to .03 kg, so I'm guessing low 30s until I weigh it on an accurate scale.



  22. #22
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    You really got the itch

    I did a similar design years ago. It turned out to be too weak, and collapsed under heavy load.

    I did a revised version later where I did the cutouts pretty much the same, but with an end mill with a radius from both sides, and left a thin wall in the center. That one worked well.

    Later I started using a mix of aluminum and composites, as that seems to offer a better weight to strength ratio.

    Soon I'll have to make some more, as I'm about to be out of rings. I guess I'll look in the direction of the Hope design, but with carbon in the mix.

    Magura

  23. #23
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    Quote Originally Posted by Mr.Magura View Post
    You really got the itch

    I did a similar design years ago. It turned out to be too weak, and collapsed under heavy load.

    I did a revised version later where I did the cutouts pretty much the same, but with an end mill with a radius from both sides, and left a thin wall in the center. That one worked well.
    Were the cutouts triangular like mine? How long did it take for the chainring to fail?

    I made the lightweight one a 32T and put it on my Blur. I am itching to get out and ride it, but the rain is hitting us pretty hard here.


  24. #24
    one chain loop
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    Shame to hide that chainring..
    everything sucks but my vacuum cleaner.

  25. #25
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    Quote Originally Posted by fishcreek View Post
    Shame to hide that chainring..
    Yeah. I should get some new bolts so I can run it without the bash guard.

  26. #26
    one chain loop
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    Beautiful work by the way
    everything sucks but my vacuum cleaner.

  27. #27
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    Quote Originally Posted by icantdrive65 View Post
    Were the cutouts triangular like mine? How long did it take for the chainring to fail?

    [/IMG]
    It looked very similar.

    It failed first time it hit a log.

    It looked good though till it failed.


    Magura

  28. #28
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    I'll ask my drawing guy if there is a shortcut, and post it if he has something up the sleeve.
    I couldn't make a CAD drawing if my life depended on it. He is on the other hand quite good.
    When I made mine, I just had the numbers on a Post-It. Not the way it's going to be in the future. Made like 3 or 4 that way.
    I downloaded some sprocket files from here to get me started:
    CAD files Chain wheels

    Still talking with the laser cutters - they won't do any machining, think flat 2.5mm will work?

  29. #29
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    Quote Originally Posted by cdn-dave View Post
    I downloaded some sprocket files from here to get me started:
    CAD files Chain wheels

    Still talking with the laser cutters - they won't do any machining, think flat 2.5mm will work?
    That's in a terrible language, and they want me to make a user ??
    Any chance we can exchange those files as emails?

    If you just have them made according to the thickness you need the teeth (8-9-10sp), and make the rest of composites, you're good to go.


    Magura

    EDIT: I just spoke to my drawing guy, but forgot to ask.....

  30. #30
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    Any chance we can exchange those files as emails?
    Sure, send me a pmail with what you need (# teeth, file format). Right now I've got 32/33/34 teeth in ProE format.

    I'm building for a singlespeed with a 3/32" (2.3mm) chain, so if that's tight I'll either file the teeth the 0.2mm or throw on a 1/8" (3.2mm) chain.

    @icantdrive - how did you figure out the height/squareness of the teeth and how does it perform? I rounded mine off (in CAD)

  31. #31
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    Quote Originally Posted by cdn-dave View Post
    Sure, send me a pmail with what you need (# teeth, file format). Right now I've got 32/33/34 teeth in ProE format.

    I'm building for a singlespeed with a 3/32" (2.3mm) chain, so if that's tight I'll either file the teeth the 0.2mm or throw on a 1/8" (3.2mm) chain.

    @icantdrive - how did you figure out the height/squareness of the teeth and how does it perform? I rounded mine off (in CAD)
    I could hardly imagine 2.5mm would be an issue with a 3/32" chain. I have made mine 2.4 as I recall. The height/ squareness, is a matter of entry/exit angle of the chain.
    In a cad system, the easy way is to draw a chain on the smallest rear you intend to use it with. Then you can see if the edges collides on entry/exit.

    You got a PM in 5. Thanks.

    Magura

  32. #32
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    Quote Originally Posted by cdn-dave View Post
    @icantdrive - how did you figure out the height/squareness of the teeth and how does it perform? I rounded mine off (in CAD)
    I just copied what is already out there and working. It works great so far. I have not had much chance to test it out since the first ride. We are getting hit with a pretty decent storm right now.

  33. #33
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    New question here.

    Are you cutting these from sheet stock or off the end of a billet?

    Reason I ask if sheet stock where are you getting your supplies. I need a new supplier for making skid pans for Moto Trials bikes! Mine has stopped stocking sheet aluminum, I guess the race car business dropped off for him.

    On another note, love your designs so far, the bash guard is beefy and should handle a lot of abuse.

    Thanks

  34. #34
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    Quote Originally Posted by NEPMTBA View Post
    Are you cutting these from sheet stock or off the end of a billet?

    Reason I ask if sheet stock where are you getting your supplies. I need a new supplier for making skid pans for Moto Trials bikes! Mine has stopped stocking sheet aluminum, I guess the race car business dropped off for him.

    On another note, love your designs so far, the bash guard is beefy and should handle a lot of abuse.

    Thanks
    Thanks. I have just been using 1/8" 6061 sheet that I have on the shelf. I am having trouble finding a supplier for thin 7075 sheet. At least an affordable one.

  35. #35
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    Rio Tinto Alcan - Home Page

    Those are the guys we call Alusuisse around here. They got anything you can imagine, and then some.

    Magura

  36. #36
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    Quote Originally Posted by Mr.Magura View Post
    It looked very similar.

    It failed first time it hit a log.

    It looked good though till it failed.


    Magura
    The question is: Do people want a lightweight chainring or do they want one that stands up to abuse? Aren't bash guards for people who want to grind logs and rocks? Just trying to find the balance. Now I want to mount it on the XXIX without a bash guard.

    I took the lightweight ring out for a spin on my Blur today. I forgot what it's like to shift from the granny gear to the middle without all the pins and ramps on modern chainrings.

  37. #37
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    Quote Originally Posted by icantdrive65 View Post
    The question is: Do people want a lightweight chainring or do they want one that stands up to abuse? Aren't bash guards for people who want to grind logs and rocks? Just trying to find the balance. Now I want to mount it on the XXIX without a bash guard.

    I took the lightweight ring out for a spin on my Blur today. I forgot what it's like to shift from the granny gear to the middle without all the pins and ramps on modern chainrings.
    True. I just don't like stuff that breaks if you look at it wrong.
    I know for a fact, that loads of the people on MTBR don't care, as long as it's light.
    I just gave you my experience. I didn't say it was bad or wrong.
    Personally, I just hate when equipment fails, thus that design went in the bin real quick.


    To get reasonable shifting, just mount 3 or 4 pins, that helps a lot.


    Magura

  38. #38
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    If anybody needs any testing done on their chainrings I would gladly do the job for you

  39. #39
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    Quote Originally Posted by sasquatch rides a SS View Post
    If anybody needs any testing done on their chainrings I would gladly do the job for you
    That's mighty generous of you, thanks for the offer.

    Where do I send the first 10?


    Magura

  40. #40
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    You are a prime candidate to take on HBC's client list.... have a go at a 29t spiderless middleburn and i'll send you some cash and test it for you
    Trek 9.9 Superfly SL
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  41. #41
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    Quote Originally Posted by ozzybmx View Post
    You are a prime candidate to take on HBC's client list.... have a go at a 29t spiderless middleburn and i'll send you some cash and test it for you
    I hope you meant Icantdrive and not me


    Magura

  42. #42
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    I dont mind who wants to make them, i'll send the cash anywhere
    Trek 9.9 Superfly SL
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  43. #43
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    Quote Originally Posted by ozzybmx View Post
    I dont mind who wants to make them, i'll send the cash anywhere
    In that case I can inform you, that you were writing to Icantdrive65



    Magura

  44. #44
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    I was aiming it at him but just in case you were thinking about it.... put me down as your first customer
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  45. #45
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    Quote Originally Posted by Mr.Magura View Post
    That's mighty generous of you, thanks for the offer.

    Where do I send the first 10?


    Magura
    10?

    I'd gladly test 1

  46. #46
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    Quote Originally Posted by sasquatch rides a SS View Post
    If anybody needs any testing done on their chainrings I would gladly do the job for you
    BCD and tooth count? I could use some outside R&D. I have been riding the lightweight ring on both of my bikes, but can't get out much between rainstorms for the last week.

  47. #47
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    Quote Originally Posted by ozzybmx View Post
    You are a prime candidate to take on HBC's client list.... have a go at a 29t spiderless middleburn and i'll send you some cash and test it for you
    One speedbump I am running into is that I don't have all of these different cranksets to measure and test fit for splined chainrings. I honestly don't know much about them.

    I do have an old XTR crankset circa ~2000-2002. Too bad those are out of vogue.

  48. #48
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    Just got a few pieces back from anodizing.



  49. #49
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    Quote Originally Posted by icantdrive65 View Post
    Just got a few pieces back from anodizing.


    That middle one is beautiful!!

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    Those rings are beautiful.

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