t2p

I will be cutting (trimming) carbon fiber handlebars in the near future

I plan to use a hacksaw - have standard blades and also have a Park blade intended for carbon fiber

( also have a Park cutting guide )

Do you have a preference - standard blade vs blade for carbon fiber ?

Any personal size experience with the Park blade for carbon fiber ?
.

Andrew R Stewart 

Generally the finer the blade's teeth the less likely the carbon will tear or split. An abrasive blade has a far finer "tooth count" (80 grit is 80 teeth per inch, as example) then a 32, 24 or 18 tpi blade has.

Having said that I have cut dozens of bars and steerers with a sharp 32 tpi blade using light pressures and fine sand paper (actually production cloth) action of the cut's face to both smoothen the face and round/de burr the edges with no issues yet known.

Good tools are nice but experience is a greater factor. Andy

70sSanO

Andy,

Would you wrap the bar with masking tape where the cut is being made?

John

Litespud

I’ve cut a few carbon steerers with a regular hacksaw blade. I use a new blade for the purpose and wet everything down at start and during to reduce dust. Let blade do the cutting and don’t lean on it - a little slower but no splinters. Finish the cut end with sandpaper

delbiker1 

I have cut a few seat posts and cf steer tubes. I do wrap the cut area, not where the blade cuts, with tape. I also use a regular thin blade and cut slowly with little pressure, and keep checking the alignment and the cut through out the process. Sand to smooth the edges. The only guide I have used is hose clamps, but an actual guide might make it easier and keep the cut aligned. I have never had an actual failure doing this. Andrew R Stewart, IME, gives good advice.

HillRider

I also use a 32 TPI new hacksaw blade with light pressure (basically just the weight of the saw). I wrap the cut line with tape to prevent splintering and to make the marked cut line more visible. I have a cutting guide that works well but have used the edge of a radiator clamp as a guide in the past. The most important thing is to "measure twice and cut once".

Andrew R Stewart 

If the tape helps you maintain the saw cut in the right place and end up fairly straight than yes. But you say you have a cutting guide which should do both jobs. If you're thinking the tape will prevent splintering or delamination then I don't think the tape will do much.

BTW lacking a saw guide one can use two radiator hose clamps to help control the sawing line. I also find that when sawing tubes or bars if I start the cut all the way around the stock, creating a shallow groove, the saw blade will follow the path of lesser resistance (or better said the saw will want to cut where the starting groove is). I haven't had to use either of these techniques on a carbon piece as I have various guides to use on steerers and such. Andy

70sSanO

Thank you Andy.

I was wondering if the tape would help to prevent splintering.

John

hayden52

The few times I've cut CF i used a Dremel high speed cutter. No need to worry about splintering.

HillRider

If you use light pressure on the saw, particularly as you near the end of the cut, splintering should not be a problem but the tape does make for a smoother cut line.

Eric F 

I've always had easy and clean results on carbon parts with a fine-tooth hacksaw, tape, and a hose clamp as an alignment guide. A quick rub with fine sandpaper eases the edges to finish the job.

SoSmellyAir

This is timely advice as I soon need to cut a 400 mm CF seat post for a new build with a vintage (i.e., 2000) frame that has a horizontal top tube.

Eric F Andrew R Stewart HillRider delbiker1 Just buy two of these?

Everbilt 1/2 - 1-1/4 in. Stainless Steel Hose Clamp 6712595 (homedepot.com)

Other than sanding to deburr the new end, do I need to add some epoxy to prevent splintering in the future? Or would I end up supergluing the seat post in the frame?

Eric F 

I just use one, and pay attention to keeping the blade against the band. I have never dressed the cut end with anything, and haven't had an issue. Superglue would probably work (let it dry before you put the post in the frame). Clear nail polish would probably work, too.

Andrew R Stewart 

The end of a seat post is a pretty unstressed spot. Not at all what i would suspect the top of a steerer sees. I have painted the cut face of a carbon tube with both paint and epoxy. Can't say that either addition made any difference. Andy

SoSmellyAir

Thank you, this is an excellent and logical point.

Camilo

I've cut several CF steer tubes and handlebar ends and one seat post with just whatever hack saw I have on hand, and no guide. I put tape on the tube, mark a perfectly "square" circle (or several marks on the right line) around the tube where the cut needs to be, and carefully and slowly cut so that the cut follows the marked line. Nothing special except go slowly, adjust continually and dress the cut afterwards.That said, for cutting down a seat post it really doesn't need to be square at all. For steer tube and handlebar ends, it should be decently square, but exactly square is not necessary. If it is not good enough with careful free-hand sawing, you can square it off better with a file to get it within whatever personal tolerance and/or aesthetics you need.