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Cut carbon steerer tube - need Park tool SG-8?

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Old 03-24-20, 06:55 PM
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HerrKaLeun
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Cut carbon steerer tube - need Park tool SG-8?

I got a fork with carbon steerer. i ordered the Park carbon blade. I also read the Park instructions, which doesn't mention the special Park blade
I know they have the saw guide SG-8 for $43, which for sure is great. Many cheaper tools don't seem to be wide enough for carbon blades.

If I don't buy the saw guide, I plan to do what this guy did.

He uses the band clamp as a guide. At minute 9 he sands over the cut and puts nail polish on. Neither is mentioned in the Park directions. So is he doing it better than Parks? I see the benefit of sanding and nail polish.

As for the need of the SG-8 tool: My theory is since the stem cap doesn't really sit on top of the steerer (there will be an air gap) it doesn't matter if the cut is not 100% square. So the band clap or some other guide should be enough. Or will I regret not buying the Park guide?
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Old 03-24-20, 07:39 PM
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A silver Sharpie to mark the cut line! I wrapped a strip of copier paper around at the mark to get an even line all the way around.
I assume you know about the gap required below the top cap, so it can pull up to make the pre-load. Make sure you know exactly where you need to cut, and why.

I pulled the fork off the bike.
Take it outside!! I don't want carbon dust in the house, I don't want to breathe it.

I used a hose clamp. A 32 teeth per inch blade. I didn't use a hacksaw tool, just the blade in my hand. I went around and around like he did, and used very light pressure. Pretty easy.
I probably sanded the end with some 320 or 400 grit paper.
I see why shops use the Park tool. Fast and precise if you are in a hurry.

I never heard about sealing the edge.

Last edited by rm -rf; 03-24-20 at 07:43 PM.
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Old 03-24-20, 07:39 PM
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I use two pipe clamps with two aluminum stem spacers between them (so they can free spin and the blade doesn't hang up on the clamps. Sure, a cutting guide would be nice to have lying around, but in 5 years I've cut two forks. So I vote no tool. Spend that money on other tools.
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Old 03-25-20, 03:00 AM
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+1 for you don't need the tool.
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Old 03-25-20, 11:16 AM
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In the shop, putting the cutting guide on the fork makes cutting the steerer tube quick, easy and precise. Well worth having.
At home, where I've cut maybe four steerers over my cycling life, an even wrap of tape, or a band clamp is all you need. Just go slow and cut your way around the tube, not just straight through it. It will be square enough, if not perfect.
If you plan on cutting lots of tubes, or you like having all the fancy tools and guides floating around the shop to make you feel 'pro', you don't need to buy the guide.
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Old 03-25-20, 11:30 AM
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If you cut the stem long enough to require a small spacer, say 5 or 10 mm, above the stem it will provide a flat 90º surface for the top cap to sit on and make have the steer cut exactly square less important.
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Old 03-25-20, 01:50 PM
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Could always buy on Amazon and use their free returns policy when you're done
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Old 03-25-20, 02:23 PM
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Originally Posted by HillRider
If you cut the stem long enough to require a small spacer, say 5 or 10 mm, above the stem it will provide a flat 90º surface for the top cap to sit on and make have the steer cut exactly square less important.
Yeah, my plan is to keep it a bit longer to have a spacer on top. Just in case i get a stem that is higher. Or use that on a bike with longer head tube.

Originally Posted by Sy Reene
Could always buy on Amazon and use their free returns policy when you're done
I don't have a problem returning items (and successfully did so on ebay, Alieexpress and amazon) if they don't meet expectations or are not as described or bad quality. But what you suggest wouldn't meet my ethics requirements.

Last edited by HerrKaLeun; 03-25-20 at 02:29 PM.
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Old 03-25-20, 03:00 PM
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Originally Posted by HerrKaLeun
I don't have a problem returning items (and successfully did so on ebay, Alieexpress and amazon) if they don't meet expectations or are not as described or bad quality. But what you suggest wouldn't meet my ethics requirements.
Nor meeting mine either.. just throwing this out there, as it's seemingly popular to buy lots of an item in all sorts of sizes or shapes, trying them on and then sending back what doesn't meet expectations at the seller's expense. It's why I think Costco changed their policies.. people buying large screen TVs the day before the Superbowl, and returning them the day after.

This thought led to wondering if there's any 'tool rental' business out there for bike enthusiasts (eg. run out of an LBS) for those items you don't want to buy, but need eg. once a decade.
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Old 03-25-20, 03:12 PM
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I use the SG-8 Saw Guide from Park Tool, a sharp hacksaw , and a file to smooth the rough edges. I've cut several carbon steerer tubes in this fashion and it works like a charm.
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Old 03-25-20, 03:28 PM
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Originally Posted by HerrKaLeun
I got a fork with carbon steerer. i ordered the Park carbon blade. I also read the Park instructions, which doesn't mention the special Park blade
I know they have the saw guide SG-8 for $43, which for sure is great. Many cheaper tools don't seem to be wide enough for carbon blades.

If I don't buy the saw guide, I plan to do what this guy did.
https://www.youtube.com/watch?v=SoPQlxg4QXM

He uses the band clamp as a guide. At minute 9 he sands over the cut and puts nail polish on. Neither is mentioned in the Park directions. So is he doing it better than Parks? I see the benefit of sanding and nail polish.

As for the need of the SG-8 tool: My theory is since the stem cap doesn't really sit on top of the steerer (there will be an air gap) it doesn't matter if the cut is not 100% square. So the band clap or some other guide should be enough. Or will I regret not buying the Park guide?
That process works fine. I've done it twice.
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Old 03-25-20, 06:37 PM
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Originally Posted by Sy Reene
This thought led to wondering if there's any 'tool rental' business out there for bike enthusiasts (eg. run out of an LBS) for those items you don't want to buy, but need eg. once a decade.
For relatively small and cheap tools (and the Park tool is already the Bentley of those tools) the logistics probably is too expensive. Many years ago I finished our lower level. I checked out rental of a miter saw. Besides me having to drive it around, scheduling etc., one week would have cost me more than a decent saw. Well, I bought one and now 12 years later still use it on occasion. BTW, that finishing took me over a year and then some phases, so I would have had to pay more for renting the saw than for all the material and tools i bought.

Now renting a $42 tool:
- The LBS probably charges $15 for cutting it for me.... so if they charge $10 for renting, it isn't really worth it..
- I have to make arrangements, have to obey their shop hours etc
- I have to drive or ride to LBS.
- If I use their tool to not hire them to do the work for me, I get the same dirty look one gets when bringing in a bike they didn't sell.
- LBS needs to have more tools than they normally would since they always need to keep at least one of each tool in the shop for their own work.
- LBS also would work against themselves since with labor they make the most money.

The $42 bring it to my doorstep and I can do the work on my leisure in the middle of the night if I want to. I guess this is moot since I don't really need it. But even if I really needed it, buying is almost as good as renting or hiring out.
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Old 03-28-20, 06:51 PM
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So i got the blade yesterday. Never saw a carbon blade before, basically looks like someone put hard fuzzy crystals where normally the teeth are. it is a bit wider than a normal blade.

I marked the stem and put the hose clamp on the "keep" side of the mark. I cut while turning the fork. It was relatively clean cut (no delimanting). Sanded it a bit and put some car repair paint on (I didn't want to use my wife's nail polish).

I used a protective mask and vacuumed away all the filings.

If you cut a lot, I see the use of the Park tool. An LBS also has to show the customer that they do "special work with special tools one cannot do at home".
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Old 03-29-20, 07:07 AM
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Originally Posted by HerrKaLeun
- LBS also would work against themselves since with labor they make the most money.
.
I guess I was pretty much thinking that we, as cyclists and sometimes tinkerers, when we need some work of some sort done on our bikes, mostly either have a choice of:
A) buy the tool so we can do ourselves, or B) take it to the LBS to have it done.

Option A the LBS doesn't make a dime -- or at least typically the ones around here don't sell a lot of tools.
Option B -- the LBS makes some money on labor.
Option C -- they make a bit of money on the rental of a tool for some subset of the Option A pool of people.
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Old 04-02-23, 03:26 PM
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Unless you are incredibly dexterous, cutting without a guide will leave a few ragged edges. You can sand them and/or put some nail polish on the end (not a bad idea in general), but the end of the stem will be compromised to some degree.

If you use the cut guide twice, then you have paid for two visits to the bike shop.
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Old 04-02-23, 03:38 PM
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Originally Posted by shmuelyosef
Unless you are incredibly dexterous, cutting without a guide will leave a few ragged edges. You can sand them and/or put some nail polish on the end (not a bad idea in general), but the end of the stem will be compromised to some degree.

If you use the cut guide twice, then you have paid for two visits to the bike shop.
Well it’s been 3 years now since the op cut the stem wondering how it turned out for him.
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Old 04-02-23, 07:55 PM
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Originally Posted by DrIsotope
I use two pipe clamps with two aluminum stem spacers between them (so they can free spin and the blade doesn't hang up on the clamps.
This is brilliant!
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Old 04-03-23, 05:30 PM
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I've cut several forks never with any special tools. I just wrap the tube with blue painters tape then carefully measure and draw a line around the circumference where I want to cut. Then I just use a fine regular hack saw blade and carefully cut it as square as I can going slowly and watching the line. If it's visually off a significant amount, I touch it up/even it out with a flat file. I also dress both the inside and outside edges of the cut tube to round off the sharp edges of the cut slightly. The cut doesn't have to be perfect. Slightly uneven pressure due to a slightly not square cut on the edge won't hurt anything. As HillRider says above, a top spacer or the stem itself is usually (always) the point of pressure, not the top of the cut steer tube.

YMMV, but I don't think it's as fussy and difficult as it's made out to be. If I was in a shop doing other people's forks and doing it regularly, yes, I'd get the special tools. But for a home mechanic (even me who loves tools!), Nah

Last edited by Camilo; 04-03-23 at 05:36 PM.
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