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At some point in the future I'll be building up a gravel bike and I have my first ever all carbon fork. I've had a look at some guides and videos online regarding trimming the steerer, and there seem to be a variety of techniques, and I'm uncertain about the best approach.
Clearly there are health concerns around carbon dust and in the early days I recall people cutting through tape to trap any particles. One guide I've read suggests using facemasks, gloves and covering all exposed skin (although oddly no eye protection) but using masking tape to stop the cut fraying rather than to trap the dust. One video shows someone cutting through untaped carbon without gloves & (I think) mask (in this case they rotated the fork after each saw stroke); they did damp down the resultant dust with water before cleaning it up.
Do people use full PPE or is cutting through tape alone sufficient? I assume I can cut straight through the steerer rather than rotating it.
I have a saw guide that I've used on steel and aluminium steerers but I'd assume that a carbon specific saw blade is a must.
As a supplementary question, one of the videos I watched advises against having more than about an inch of spacers below the stem (this was on a 1 1/8" fork, mine's tapered) presumably to avoid snapping it. There was no paperwork with the frame/fork package I bought so I may need to talk to Ragley about any specific requirements for the fork.
I use a dremel with cut off wheel and a dust mask, outdoors if its not raining. I was cutting some carbon bars a while back and the hacksaw blade snagged one of the fibres and pulled it out of the resin, horrific 100mm streak!
Since then, always dremel with mask, zero chance of snagging.
Proper carbon blade (£10) and a saw guide (mine has a spacer you change for the wider carbon blade). Outdoors and I normally wear a mask.
I've done a few carbon steerers, wrapped a bit of masking tape around it, mraked where it needs cutting, put my steerer cutting guide on, checked my hack saw has a decent blade in it (I use a proper one not a junior hack saw), cut it off, cleaned it up with a fine file. Apart from doing it outside, I didn't really do anything different.
https://www.wiggle.com/p/lifeline-saw-guide?
I've only ever done one. I wrapped it with tape, to keep the cut perpendicular to the steerer, then cut to the edge of the tape with a good but not new Hacksaw (not Junior Hacksaw). I then ran a sharp File around the cut to clean it up.
I did this indoors, I didn't wear a mask or gloves or eye protection, I didn't worry about the dust but I did avoid breathing heavily while making the cut!
I'm very familiar with Hacksaws and how it does/should feel so you may choose to take precautions that I didn't feel I needed.
Same as @jag. Carbon is much easier to cut than alloy or steel. I keep a 2.5 mm spacer above the stem, so set the cut by spacing with spacers and stem and added a sacrificial spacer of 1.25 mm. Cut against that and slip on the 0.25 mm. I did clean up a little with a file.
I have done quite a few carbon steerers and only ever used a fine tooth hacksaw blade (32tpi IIRC). I mark then just spray it with water a few times to keep the dust down. Sandpaper to tidy the cut afterwards.
As per @Jamz = 32TPI blade and water to wash away the particulates. Realistically I suspect you only really have to worry about the particulates if you're working on an industrial scale, not above the kitchen sink, but it does feel better seeing the black stuff wash away.
Two old stems to make a guide, masking tape and a fine toothed saw.
I've cut several, just use a normal hacksaw and vacuum up the dust afterwards using the workshop vacuum, which has a decent filter (Festool).
I didn’t find that much dust came off it cutting it with a hacksaw. I didn’t use a specific carbon blade - I just used a hacksaw blade with the DH ear teeth possible. I put some tape around and cut through that as some videos online showed that. I’ve got a Lifeline cutting guide so got a perfect straight cut - make the blade do the work - don’t try and push down through the steerer quickly. Was a lot easier then I expected.
Great thanks.
So if I pop along to B&Q and get a 32tpi blade that'll be fine, I don't need anything specifically rated for carbon fibre?
I have a saw guide, they're great bits of kit.
Ragley state there are no maximums for spacers under the stem but recommend no more than 40mm to avoid flex.
Go to toolstation, part no 48146 gets you a tungten carbide grit blade that's ideal for the job, and comes in around £1.50
Most common issue I see is people tearing fibres out the bottom of the cut (aside from cut squint obviously). When its cut most of the way through it is easy to put too much down ward pressure and snag, I like to support the offcut as I finish the cut. I keep meaning to make a saw guide that clamps both side of the cut
I prefer a 32tpi blade to the the abrasive ones.
A little bit of care and you can get a good result in a short time, I use a sponge sanding block to smooth the cut out.
Most common issue I see is people tearing fibres out the bottom of the cut
This. Score all around with the saw and then cut through while supporting the offcut as suggested
I just use a bogo bi-metal hacksaw blade with the fork resting on my workmate.
If you can't cut a straight line with a hacksaw, practise a few times on something nondescript.
Thanks everyone. Will these do https://www.screwfix.com/p/magnusson-32tpi-multi-material-hacksaw-blades-12-300mm-5-pack/5846v https://www.screwfix.com/p/magnusson-32tpi-multi-material-hacksaw-blades-12-300mm-5-pack/5846v
Wiggle have a Lifeline one (£9.99) that they describe as a grinding blade specifically for carbon.
PJay - Yep they (Screwfix ones) will do this job and every other job you need a Hacksaw to do :o)