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This is a sequel to an earlier question.

Park Tool's CN-10 (and similar, such as Pro's Team Cable Cutter, Jagwire's Pro Cable Crimper and Cutter, Pedro's Cable and Housing Cutter, Feedback Sports' Cable and Housing Cutter, Shimano's TL-CT12 Cable Cutter, and others), is labeled "cable and housing cutter".

But in Park Tool's own video Calvin Jones uses the side cutter pliers SP-7 for cutting (brakes) wound housing.

Is the (brakes-specific) wound housing too tough for the CN-10? I have enough extra cable length to experiment, but I'd rather not risk damaging the CN-10.

Will good hardware-store side cutting pliers (aka diagonal cutting pliers) do the trick, or is the SP-7 (or similar) really necessary?

Another experiment, as mentioned in an answer to the question quoted above, is to use a Dremel circular cutter. There I'm less worried about damaging something than having a circular cutting tool fly off into a body part (and I won't know whether I can do it fast enough to avoid heat that will melt the plastic parts until after the fact).

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  • To me a proper brake/shifting housing cutter like the CN-10 looks much more effective and suitable for cutting steel wires than a normal cable cutter an electrician would use. Knipex specifies the maximum diameter of "hard" (steel/iron) cable you are supposed to cut with their electrician cutters. For most side cutters similar to the SP-7 they only allow up to 2mm. Example: knipex.com/products/cutting-pliers/diagonal-cutters/…
    – Michael
    Commented Aug 23, 2022 at 17:35
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    @Michael Thanks. That's my feeling too. The CN-10 is curved to ensure that what's being cut will not slide out. My problem is that they themselves say it's not the right tool.
    – Sam7919
    Commented Aug 23, 2022 at 18:02
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    Cynically, park tool videos show a lot of tools, implying you need to buy them all. You don't.
    – Criggie ♦
    Commented Aug 23, 2022 at 23:46
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    With the Dremel you want to work slow, not fast. Speed is what builds up heat. I’ve cut every style of housing out there with a Dremel and it doesn’t melt if you take your time.
    – MaplePanda
    Commented Aug 24, 2022 at 3:03
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    @Sam I concur with MaplePands's approach. With brake housing I prefer to use a Dremel with a thin cut off wheel and work slow, and take a few breaks. It won't hurt to take the time, and the result should be a clean, square finished cut. I use the Shimano version of the Park CN-10 for cables and shifter housing, but for brake housing, the Dremel is my preference.
    – Ted Hohl
    Commented Aug 24, 2022 at 5:19

3 Answers 3

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Tools like the CN-10 and other bike-specific cable and housing cutters are meant to do one thing that other cutting tools struggle with: cut compressionless housing (parallel or braided wires) cleanly without any crushing or other mangling. They do it by cutting into all sides simultaneously.

Compressionless housing cutters are also good at cleanly cutting brake and gear inner cables, but good quality side and diagonal cutters do that too.

They cut through spiral housing without issue, but they don't typically do it as cleanly as a good side or diagonal cutter with good technique behind it. They're not designed to make it easy to slip in between coils on a spiral housing and cut it without any crushing of the spiral form, which has to be cleaned up if it occurs. That's not to say they can't be used for the purpose, because many people do and it can still be cleaned up to a fine result, but they are not optimized for the purpose. Some are less bulky and prone to those issues than others (the Shimano ones are relatively slender for example).

Side and diagonal cutters (they're used somewhat interchangeably on bikes) are a tool that vary enormously in quality. A lot of bad ones are not capable of cutting spiral housing cleanly either because they're not hard, sharp, and/or gapless enough. Since a lot of people only have examples of this type around or that's all they've ever handled, it can lead to a murky conversation about what they're capable of categorically. The very best diagonal cutters in good, sharp condition actually do a good job on even compressionless housing (I've only seen Knipex ones do this), although they still crush the housing more than a cutter made for the purpose.

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  • It’s a bit unclear what “they” refers to in the second and third paragraph.
    – Michael
    Commented Aug 24, 2022 at 6:00
  • For those of use that do a fair bit of electrical work, the idea of using our good side cutters on steel is almost painful (obviously the thing to do is get a 2nd set, but good cutters for steel that big are rather expensive)
    – Chris H
    Commented Aug 24, 2022 at 20:31
  • @ChrisH is it being steel really what's in question though? spiral housing doesn't seem very hard. the park side cutters are a basic chinese cheap one and they don't wear out particularly fast in daily use.
    – Nathan Knutson
    Commented Aug 24, 2022 at 22:16
  • @NathanKnutson good cutters for copper tend to be sharpened to a finer angle than for steel and are more easily damaged. The cutters I've visibly damaged on bike cable housing were big cheap ones meant for fat electrical cables. I bought some meant for steel and they did much better
    – Chris H
    Commented Aug 25, 2022 at 5:33
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In various busy workshop environments I have personal experience of, the CN-10 is the preferred tool. It is an absolute animal and extremely durable. Wear can also be adjusted out.

You are right that is can occasionally deform the end of spiral brake housing. This is avoidable but if it does happen there are two approaches to cleaning it up quickly:

  • Cleanest finish: Touch the cut end to a bench grinder for a very clean square finish. Takes a second or less (once the grinder has spun up). Does not melt plastic outer.
  • No bench grinder: Use your CN-10 or other cutters to nip off the small bit of spiral that is reducing the cable aperture. It's easy enough to do and this is most commonly done when the "perfect finish" isn't required or the bench grinder is unavailable.

I don't see the need for a tool like the SP-7 in a workshop dealing with the majority of bicycles. I would rather invest in a good quality pair of scissors.

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  • A hand file works surprisingly well too - 5 strokes should clean it up, and probably quicker than the grinder's spinup time
    – Criggie ♦
    Commented Aug 24, 2022 at 22:07
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Just wanted to document what one can do with just the CN-10.

The cut on the left is the result of using the CN-10 once on the wound cable. In the second image on the right I used the same tool to cut only a portion of the helix, with the objective of exposing the interior plastic sheathing to make it more likely that (during handlebar turns or other cable movements) the interior plastic sheathing will be the one that will touch the cable, not the wound helical steel cable.

left: after one cut; right: after the second cut

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