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Singlespeed & Fixed Gear "I still feel that variable gears are only for people over forty-five. Isn't it better to triumph by the strength of your muscles than by the artifice of a derailer? We are getting soft...As for me, give me a fixed gear!"-- Henri Desgrange (31 January 1865 - 16 August 1940)

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Old 10-20-06, 10:00 AM   #1
Davidnssbm
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Cutting Carbon Fiber [Risers] ... How

My buddy picked up some Carbon Fiber Risers and they are way too wide. How does one go about cutting this? I hear the fumes/dust are dangerous, and any wrong move could thread the whole thing to ****...

Anyone have any advice?
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Old 10-20-06, 10:11 AM   #2
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trackstar cut mine for me no problem.
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Old 10-20-06, 10:18 AM   #3
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yeah, don't breathe the dust. i believe it contains many very fine, sharp grains and can do you damage. keep your skin covered and wear hand, eye and mouth protection.

otherwise, it's pretty straight forward. use a fine 32 tpi hacksaw and keep your cutting site wet to keep the dust down. some people wrap the cutting site in electrical or masking tape. helps to use a mitre to keep the cut straight, but otherwise, measure twice, cut once.

when the cut is done, finish the end off with some fine 400 grit sandpaper.

also, it may sound obvious, but be sure to cut an equal amount off each side. there's a bulge in the middle.
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Old 10-20-06, 10:25 AM   #4
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HIgh speed cutting disc - i.e. dremel w kevlar disc. Lots of dust, so wear a mask , eye protection and wash afterwards. The dust may irratate your skin and lungs. SOme people have used VERY FINE hacksaws with no KIRTH/KERF/KIRF(?), but you will ruin severial blades before you are done. After you are finished, I would recommend sealing the ends of the bars w epoxy or at lease super glue. Smooth out everything w very fine sand paper after the superglue dries. These last 2 actions reduce the prob of fractures in the future and keep you from hurting yourself. Good luck,.
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Old 10-20-06, 10:32 AM   #5
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I used a hacksaw to cut the steerer on my CF fork; do it outside, in the wind because if you breathe in that dust, you DIE! RIGHT AWAY!
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Old 10-20-06, 10:36 AM   #6
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Just cut them the dosn't isnt going to kill you. We put carbon fiber parts on bench grinders and **** all the time at the shop and never cover our mouths, but maybe were just cool like that.

Put some super glue on the end of the bars so to reseal the epoxy stuff or whatever.
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Old 10-20-06, 10:42 AM   #7
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i would be very careful cutting carbon bars. i believe that if you go to eastons website they tell you how to do it.
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Old 10-20-06, 10:52 AM   #8
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Quote:
Originally Posted by recneps
Just cut them the dosn't isnt going to kill you. We put carbon fiber parts on bench grinders and **** all the time at the shop and never cover our mouths, but maybe were just cool like that.

Put some super glue on the end of the bars so to reseal the epoxy stuff or whatever.
this guy dropped dead 2 minutes after writing this post.
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Old 10-20-06, 11:10 AM   #9
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The dust doesn't kill you, but silicosis is not fun. That **** only appears after a while, but when it does, it sucks big time. (I think CF powder works like carbon dust in mines in this regard. Not sure.) I'd wear a mask to be on the safe side.
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Old 10-20-06, 11:59 AM   #10
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Yeah, and recneps, start wearing the proper breathing filters when working with this stuff. I bet you're young enough to still have an immortality complex, so I say this as strongly as I can: you WILL deal with the consequences of everything you do when you're older.

LoFarkas is right, go google up silicosis, black lung disease, etc. and become paranoid, please.
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Old 10-20-06, 12:52 PM   #11
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I i have aluminum bars with a carbon fiber cover would i still need to super glue/epoxy the end.?
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Old 10-20-06, 02:40 PM   #12
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Quote:
Originally Posted by poopncow
HIgh speed cutting disc - i.e. dremel w kevlar disc. Lots of dust, so wear a mask , eye protection and wash afterwards. The dust may irratate your skin and lungs. SOme people have used VERY FINE hacksaws with no KIRTH/KERF/KIRF(?), but you will ruin severial blades before you are done. After you are finished, I would recommend sealing the ends of the bars w epoxy or at lease super glue. Smooth out everything w very fine sand paper after the superglue dries. These last 2 actions reduce the prob of fractures in the future and keep you from hurting yourself. Good luck,.
Respectfully... poopncow's suggestions above are overkill and fairly misinformed. There's no need to use a rotary tool ("Dremel") at all. In fact, you'll have more trouble cutting the bar in a straight line, since the tool is spinning so fast and generating it's own torque, your "line" will be difficult to control.

Also, because the diameter of the rotary tool's kevlar disc is smaller than the diameter of the bar, you won't be able to cut the bar in one pass....you'll have to cut from one side, and rotate the bar a "quarter turn" and cut again, and rotate the bar a "quarter turn" and cut again, etc..... Not easy or good.

You can, and should, use a regular fine-tooth hacksaw to cut carbon. The same kind of saw you would use to cut metal. It will glide thru carbon fiber bars, seatposts and/or fork steerer tubes quite easily, and you won't ruin the blade at all. In fact, it will only take you about 40 strokes to cut thru a normal bar, cutting with moderate pressure, and the blade will still be pretty darn sharp when you're done. Sharp enough to cut a dozen bars with the same blade, if you wanted to.

Also, "Sealing" the ends of the cut carbon with glue or epoxy serves no logical purpose.
If you cut the carbon straightly and cleanly, it's not going to unravel or "fracture".

I have personally crushed many carbon parts in a bench vise. I've smashed carbon road bars with a hammer. I once banged a carbon fork against concrete until it broke. Carbon fiber is much, much stronger than most people think. Use common sense and you'll be fine.

More info here: http://www.eastonbike.com/downloadab...-05-Carbon.pdf
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Old 10-20-06, 02:44 PM   #13
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*feeble cough*
..I think I've got the black lung, pop.

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Old 10-20-06, 03:44 PM   #14
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You can finish up the ends with some clear nail polish.
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Old 10-20-06, 04:02 PM   #15
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I've always favored a good chainsaw, but that's me.

If you can't do that, then settle for a 32tpi hacksaw. Cut straight, cut deep.
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Old 10-20-06, 05:28 PM   #16
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Hacksaw, 32tpi blade, table vise with nice fork cutting tool mounted, cutting fluid, measure twice/thrice, cut once.
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Old 10-20-06, 05:40 PM   #17
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Mcmaster-carr has some diamond edged blades for chop saws that are made for cutting carbon and phenolic ect, but theyre 200 or so dollars a piece.
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Old 10-20-06, 08:10 PM   #18
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Note to self take other peoples advice.

Maybe I'll just wrap a t-shirt around my mouth when cutting them from now on.
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Old 10-21-06, 01:31 AM   #19
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just use a hacksaw with a decent blade on it. if you are being carefull put a wrap of electrical tape around the line you are cutting. take your time, measure alot.

power tools=death to bike.
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