# Tips for cutting a carbon ISP and fork.



## JPDynamics (Sep 27, 2010)

Hey everyone,

So building up a bike has been something i have wanted to do for a while now and i have recently purchased my first carbon frame with an integrated seat post and carbon fork. I like to do my own bike maintenance but unfortunately cutting carbon is something i have never encountered before. I actually used to work construction so i am good with tools and i have cut many metal pipes but never carbon. Does anyone have any tips or tool recommendations for cutting the ISP and fork. I know how long my ISP/fork have to be and i would rather not have to take it to Performance Bikes where they would charge me $60 for 1 hr of labor and $50 to make the cuts. Any help would be appreciated.


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## MarshallH1987 (Jun 17, 2009)

I used a 32 tooth fresh hacksaw blade when i cut my steer tube. I figured out the length i needed, put an old stem on just below where i wanted to make my cut then followed it as a guide. I think i used some really fine sandpaper to clean up the edges after.


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## baker921 (Jul 20, 2007)

I think I'd try and find a better bike shop before going down the D.I.Y. route.
In these situations I always ask myself three questions:
- Have I done it before?
- Do I need special tools?
- What is the cost of failure?


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## Salsa_Lover (Jul 6, 2008)

It is an easy job

- figure out the right height.
- setup a cutting guide, most new frames come with the cutting guide.
- hacksaw
- remove cutting guide
- finish imperfections with a file or sandpaper

done.


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## charlieboy (Sep 10, 2003)

*measure twice cut once!*

It's as others say - just take it easy. If you have experience with handtools, as you have, you should be fine...

Measure and measure again (and once more for luck)
Be sure you are following maker's instructions re seat post height and amount of steerer to leave above the stem and spacers etc
Use a cutting guide
Wear a mask 
Use a new blade on your saw - carbon-specific not necessary IMO, just a good quality fine tooth one will do
Saw steadily
Cut half way from one side then rotate and cut through from other side to avoid any fraying/splitting at final few strokes
Sanding/finishing the cut - do it 'with the grain', again to avoid any fraying of fibres


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## Andrea138 (Mar 10, 2008)

Put masking tape around it when you're cutting. That helps cut down on splits in the top layers of carbon.


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## ewitz (Sep 11, 2002)

if you want to really do it right. Takes a little more effort but the end result is flawless.

For $8 it is hard to argue

http://bike.com/park-tool-csb-1-carbon-cutting-saw-blade-park-tool-bike-tools


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## damnilocano (Feb 10, 2010)

Definitely get the carbon blade for the hacksaw. My "mechanic" recommended I get one if I were to DIY on my TCR Advanced SL.

He uses a sweet repair stand. I'm guessing you'll need one that can rotate unless you want to make the cut horizontally.

Has one of these: http://www.giant-bicycles.com/de-at...ct/carbon.seat.post.clamp.adaptor/2803/37927/

Here's Giant's how to: http://docs.google.com/viewer?a=v&q...2dhUdY&sig=AHIEtbQYBIRnSDf05Oxqvt92B5nBR3bWrg

Good luck with it.. I'm scared of ISP's.


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## rx-79g (Sep 14, 2010)

A regular fine hacksaw blade will work fine. I like to use clear packing tape to wrap the area to be cut, use some sort of cutting guide, and use the saw to score all the way around what you're cutting before sawing through.

If possible, do it outside in a breeze to carry the fibers away from you. Rinse with water, wet sand if necessary (but it shouldn't be), then rinse again. Make sure you fully understand the way the seat thingy attaches and how you want to stack the steerer and reinforce it from the inside with a good plug before cutting. Longer is always better than too short, yo.


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## tuffguy1500 (Jul 17, 2008)

baker921 said:


> I think I'd try and find a better bike shop before going down the D.I.Y. route.
> In these situations I always ask myself three questions:
> - Have I done it before?
> - Do I need special tools?
> - What is the cost of failure?


^^^^^^ this
I used a tube and seat post cutting guide/clamp to my aero seatpost and cf steerer tube. I didn't want to risk free-handing a cut. Results were spectacular, and like you, this was my first carbon bike/fork/seatpost so i wanted to ensure it was perfect.


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## JPDynamics (Sep 27, 2010)

Thanks for the replies everyone, it makes me alot more confident. I am going order a repair stand, carbon blade and a saw guide from park tools. 'And while we are talking about forks, is there a maximum height for carbon spacers?

Also does anyone have any recommendations for some anti seize or grease?


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## bmxhacksaw (Mar 26, 2008)

So you'd rather buy $300 worth of tools then pay a shop $20-40?


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## rx-79g (Sep 14, 2010)

bmxhacksaw said:


> So you'd rather buy $300 worth of tools then pay a shop $20-40?


How is an $8 cutting guide and a hacksaw blade $300, let alone $20?


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## SilverStar (Jan 21, 2008)

rx-79g said:


> How is an $8 cutting guide and a hacksaw blade $300, let alone $20?


Did you miss the part about the repair stand? Technically, it's not a tool but is a fixture, but still...even a cheap one isn't that cheap.


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## looigi (Nov 24, 2010)

baker921 said:


> I think I'd try and find a better bike shop before going down the D.I.Y. route.
> In these situations I always ask myself three questions:
> - Have I done it before?
> - Do I need special tools?
> - What is the cost of failure?


^^^^^ This?

- If not having it done it before is your criterion, you'll never do anything.
- Goody. Another tool buying opportunity.
- No guts, no glory. No risk, no reward. No sense of accomplishment.

You don't need a work stand to cut a steerer, last time I checked. It is handy to have for many other purposes, including routine cleaning and lubing of the bike. You pay for the tools and you still have them when you're done. You pay the bike shop and you got nothing to show for it...except less steerer.

If you're going to pay a shop to cut your steerer, why not pay somebody to ride the bike for you too? 

HTFU

IMHO


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## rx-79g (Sep 14, 2010)

SilverStar said:


> Did you miss the part about the repair stand? Technically, it's not a tool but is a fixture, but still...even a cheap one isn't that cheap.


I was kinda taking it for granted that a repair stand is good for other things besides cutting a seat tube, and will continue to be useful for general maintenance, saving future visits to the LBS.

It is also unnecessary for the job at hand. So I don't see it as a cost to do THIS job.



Despite all the how-dee-do, cutting carbon is not a big deal.


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## PoorCyclist (Oct 14, 2010)

the frame didn't come with a guide with a slot to cut the post?
which makes the job almost fool proof, after the cut, slide the guide down the post and use it as a guide to file the edges flush.
(describing what the LBS did for $30) they put the frame upside down on a work stand.


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## JPDynamics (Sep 27, 2010)

Unfortunately my LBS is performance bike shop who charges out the *** for any type of work done. For this job they quoted me $60 for an hour of labor and an additional $50 for the two cuts. I do not know if this would be cheaper than buying all the necessary tools/stand (which i now understand i do not need for this job) but i would rather learn how to build a bike even though it might not be the best option money wise. I am picking up a repair stand because at the moment i do not have one and i know i will need one for future maintenance and repairs. Anyways thanks again everyone for the input, i really appreciate it.


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## looigi (Nov 24, 2010)

JPDynamics said:


> ...i would rather learn how to build a bike even though it might not be the best option money wise. I am picking up a repair stand because at the moment i do not have one and i know i will need one for future maintenance and repairs...


Bingo. Give that man a cigar!


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## Mel Erickson (Feb 3, 2004)

Two metal hose clamps for your cutting guide. Fifty cents a piece but you probably have a couple laying around.


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## Kristatos (Jan 10, 2008)

Bravo! All good advice in this thread except the parts about handing your new beauty over to some snot-nosed wrench at an LBS to hack it up thinking they'll do a better job. 

Regarding spacers on your fork there's no max height unless the manufacturer says so. Obviously you have to be able to fit the stem though, with the top bolt of the stem above the top edge of the steer tube.

On the grease question - which parts exactly are you referring to? 

Also, on the fork what type of expander assembly came with it? Does it have a sleeve that you glue in or something else like an expander bolt?



JPDynamics said:


> Unfortunately my LBS is performance bike shop who charges out the *** for any type of work done. For this job they quoted me $60 for an hour of labor and an additional $50 for the two cuts. I do not know if this would be cheaper than buying all the necessary tools/stand (which i now understand i do not need for this job) but i would rather learn how to build a bike even though it might not be the best option money wise. I am picking up a repair stand because at the moment i do not have one and i know i will need one for future maintenance and repairs. Anyways thanks again everyone for the input, i really appreciate it.


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## baker921 (Jul 20, 2007)

Kristatos said:


> Bravo! All good advice in this thread except the parts about handing your new beauty over to some snot-nosed wrench at an LBS to hack it up thinking they'll do a better job.


Nice own goal Kristatos. The good advice came from bike shop wrenches who I and many others rely upon to help us. My advice was to find a better bike shop, but with the reassurance of forum "experts" it seems that this can be a safe D.I.Y. job.


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## Kristatos (Jan 10, 2008)

baker921 said:


> Nice own goal Kristatos. The good advice came from bike shop wrenches who I and many others rely upon to help us. My advice was to find a better bike shop, but with the reassurance of forum "experts" it seems that this can be a safe D.I.Y. job.


Trust me there are plenty of LBS wrenches in my area that would mess it up badly. For sure there are some that might do a better job than I could but the difference would be negligible. I doubt many come into these forums seeking advice just to then hand their bike over to their LBS blindly. Try not to be so sensitive.


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## SilverStar (Jan 21, 2008)

rx-79g said:


> I was kinda taking it for granted that a repair stand is good for other things besides cutting a seat tube, and will continue to be useful for general maintenance, saving future visits to the LBS.
> 
> It is also unnecessary for the job at hand. So I don't see it as a cost to do THIS job.
> 
> ...


Aw...I was just messing with you. And you're right on both accounts.

For me, ANY excuse to buy tools is acted upon with no hesitation!


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## JacksonDodge (Mar 26, 2006)

Kristatos said:


> Try not to be so sensitive.



Try not to be such a pompous DB.


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## urawildman (Aug 16, 2009)

Tape the ISP and stuff the inside with tissue. You don't want carbon dust in your bottom bracket.
Carbon dust..avoid getting on your bare skin; and DO NOT breathe in the dust.
Sanding block for finishing touches
Good luck


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