[Closed] Cutting carbon

Don't use a tube cutter. No, no, no, no, no!

Use a nice fine tooth hacksaw blade and an old stem or two as a guide or a proper saw guide or some old spacers to protect decent stems if you don't have any old ones or a guide.

Do it outside and clean up with soapy water over the drain and you can cut it wet if worried about dust. Clean up the cut with some fine wet and dry (wet).

Thanks andyl

No worries. If you are brave and have an angle grinder with a diamond blade then it will be done in seconds 😉 but use plenty of water. I'd probably suggest the hand saw route and measure at least 3 times though.

Yeah measure twice (or 3 times) cut once

It's a fine DIY job if you're careful. Have you got a cutting guide? They're pretty useful as it's hard to file down a carbon steerer without it fraying.
A carbon saw is basically a normal hacksaw blade but blunted, so if you'd got one lying around use that. And wrap some electrical tape around the area that you're cutting so it doesn't splinter.

A proper diamond carbon saw won't fit in the slot of a cutting guide as it's too fat, so use the guide and a standard hacksaw blade. The cut doesn't actually have to be perfectly square because the cap will accommodate a small angle.

The best advice I can give is to secure the steerer firmly in a vice (not so tight as to crush it, obviously), use a new blade and and go at it with firm, even strokes so as to keep the cut neat and prevent fraying and mess. Then finish off with wet 'n dry or wire wool.

Better off with a dull blade actually, not a new one.

Standard hacksaw here, just use a bit of tape a guide.

I have actually done it with a tube cutter in the past and I've not died yet. Reckon it's fine as long as you go very slowly and don't crush the tube.

go at it with firm, even strokes

😀 😳

Might be worth buying one of those clamp on guides or use an old stem so you've got something to saw against and keep the cut straight .. Not sure I'd just use tape unless you go really slow

I have actually done it with a tube cutter in the past and I've not died yet

Are you sure?

Just out of interest, what's the reasoning behind using a blunt blade rather than a sharp one?

Dremel cutting disc ftw

Are you sure?

Well it's not exploded in a fireball in the last year. And I probably applied less force than a stem clamp does.

Wrap it in masking tape mark where you want to cut with a biro,
Check it , then check it again.
Then assuming you don't have a proper cutting guide slide a old stem up(or down) to just below your mark and clamp loosely then cut very slowly with a fine toothed hacksaw blade.
Once cut remove everything and if done properly there should be very little to clean up, I normally just take off any edges with some wet-n-dry.

Hacksaw for me on road bike, no issues, just take your time.

I used a tube cutter very loosely to mark a line around it, as a faint scratch. Then I went round with a junior hacksaw just deepening the line slightly, round and round cutting slightly more each time until there was enough of a groove to make five or six cuts through. Each cut was downards into the wall of the tube, never got the hacksaw halfway through the tube so the teeth were never pulling sideways on the fibres.

Old stem idea is a good one though to make the mark.

Oh and in the instructions for mine, it said I had to leave 10mm above the stem at all times, which is a little annoying as I already had about 15mm of spacers for future adjustment capacity, so now it looks sub-cool.

32tpi hacksaw blade, park cutting guide in vice, steerer tube wrapped in masking tape to prevent delamination. Lubricated with soapy water. Cut softly (flatter angle than usual 45 degrees) with wetted rag under cutting guide, over large dustbin with bin bag. Mask, disposable gloves and safety glasses.

After cutting, rag and contents into bin, steerer finished with fine grit paper and soapy water over bin. Then mask and gloves into bin, bin bag sealed.

I've cut 100s of carbon steerer's and integrated seatposts 🙂

Rofl ^^^^ how much dust were you expecting ? You hardly get a fallout from cutting a small carbon tube .

As someone has said above, masking tape wrapped around several times to stop it fraying. This also allows you to clearly mark your cut line with pencil (or biro)

Edit - and yes, use a hacksaw, I used a non-new 32tpi (metal/plastic) blade.

I suspect filing any significant amount off would be difficult - I used a file (going up the steerer to avoid fraying) to lightly tidy things up once I'd cut it but I imagine actually trying to remove length could lead to significant fraying.

Fine hacksaw and and old stem as a guide. Once you've finished cutting, leave the stem on and use a flat metal file to remove the excess.

I certainly seem to take a more laissez faire approach than many it would seem.
I just rest fork on end of table, cut by eye with hacksaw and blow off any dust.

Only difference for me between alloy and carbon steerer is that the carbon one is a few seconds quicker to cut.

fine tooth hacksaw at 1am in the morning done hurriedly because you've got to be up early in the morning to go for a ride. don't worry about the dust or little frayed edges as they'll be covered by the stem.
bish bash bosh. done.

kerley is going to DIE*

*i don't know why though

kerley is going to DIE*

*i don't know why though

We are all going to die. If the cause of my death could be linked to my carefree approach to cutting carbon steerers and bars I would be amazed.

There are 1,000s of things that would get me first