Re: I want to build my own front sprocket! but how?FoSi wrote:
> Earl Bollinger wrote:
>>"FoSi" <email@example.com> wrote in message
>>>recently i converted my bike to SS fixed gear! using 17rear sprocket
>>>33front sprocket! i have horizontal "drop-out" so i made a 10mm rear
>>>Cr.Mo bolt axle to fit my Deore Hub! then i also did machined two chain
>>>tensioners.. to micro-adjust the tension, and to have the wheel always
>>>in place! untill here everything its fine!
>>>so.. i purchased a BMX 1/2x1/8" chain, puted it in place.. and noticed
>>>that the i need a thicker 33t sprocket at front!! like those BMX
>>>sprockets to fit the 1/8 chain... so im thinking in designing and
>>>building my own 33t front sprocket in 8mm 7075 aluminium !
>>>but i dont know were i can find technical info on how the sprocket is
>>>designed! is there a document with the standards for this?
>>>my setup>> http://img127.imageshack.us/my.php?i...procketbq6.jpg
>>>i have a 4bolt truvativ hussefelt crank, with the standard truvativ 33t
>>>Cr.Mo sprocket.. i need to design a BMX thick 33t sprocket
>>>like these: http://wethepeople.de/V3/bilder/product/war119_004.jpg
>>>(equal to this one, but to fit the 4bolt crank arm)
>>>can someone please helpme to find technical info about the bmx sprocket
>>>design + plus the truvativ 4bolt crank arm radius? this would be really
>>>thank you very much for reading
>>Well, you could make your own. But you need a new chainring to use as a
>>pattern, so you can get the teeth done OK without using a worn chainring
>>with worn down teeth.
>>Then you use a rotary table mounted on a milling machine. Drill the center
>>hole in a plate of aluminum or steel your choice of suitable thickness.
>>Then carefully mill out the circular shape in the plate of metal.
>>Then carefully mill out all the teeth. Then after you have your internal
>>pattern shape doen, mill out the internal web design.
>>Finally angle the rotary table and carefully mill out the angles as best you
>>can on all the teeth. You could even use a hand file or two to do this part
>>Now you could use a CNC machine, but the devil is in the details, as you
>>have to program in your chainring design. For some people this can be a
>>major project in itself. But once you have the CNC program done and working
>>well, you can save it and reproduce your chainring anytime you want to.
> Hi Earl!
> thats why i asked for the bmx sprocket standard technical paper/draw!
> so i dont need a pattern.
The 'recipe' is always secret. Once you have the 'recipe' anybody can
cook. Try TA, Shimano, or Campagnolo for their drawings or 3D models.
Posted by news://news.nb.nu