# Crown Race Cutting Tool – Always Required?



## jandras (Jul 4, 2006)

OK, dumb question here. I am building a bike from new parts and am starting to work on the fork and headset assembly and, more specifically, on pressing the crown race onto the fork’s crown race seat.

I am using a Cane Creek 110 IS headset and a DT Swiss XMC 130 fork with a 1-1/8” steerer tube.

I bought a Park Tool CRC-1 crown race cutting tool for this job, but I’m not sure it’s necessary.

The inside diameter (ID) of the crown race is 29.90mm. The outside diameter (OD) of the fork’s crown race seat is 30.03mm. That's a difference of .13mm and, according to the Park Tool website, "A difference between 0.05mm to 0.15mm is generally considered acceptable."

And, although it appears anodized, the fork's crown race seat looks precision machined, as is.

Bottom line, I am questioning whether or not I need to use the crown race cutting tool at all.

In fact, the Park Tool CRS-1 crown race cutting tool’s cutter is a 30.1mm cutter which is just a bit bigger than the 30.03mm diameter already on the fork. Based on dimensions alone, it seems to me that it wouldn’t do anything.

On the other hand, the instructions that came with the headset say it is “imperative” to use a crown race cutting tool to “turn and face the crown race seat of the fork” for “ALL frames and forks, new or used, painted or unpainted.” The fork did not come with any useful instructions on this issue.

Thoughts?

Thanks all.

Joe


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## Elvota (Oct 30, 2008)

In my 20 plus years of being behind the bike counter and in front I have never used a crown race cutting tool on anything.

I'd find it hard to believe that you could get a result more precise with a hand tool than straight from the factory production line.


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## Mike T. (Dec 30, 2003)

In decades of installing headsets I have yet to find a fork that needed the crown race seat cutting. The headset makers are just doing CYA (cover yo' arse).

I compliment you on taking precise measurements. Very few headset installers ever do. Whack away!


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## Jerk_Chicken (Oct 13, 2005)

I never even knew this tool existed. Just put the race on and continue with the build.


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## mx_599 (Dec 10, 2005)

i have this tool and use it all the time. however, i agree with the others as well. since you have it, run it lightly. if the fork is machined nicely then it will just skim the surface. it won't hurt it.

this isn't any worse than people chasing threads excessively...which can over-cut threads.

mx


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## jandras (Jul 4, 2006)

Thanks guys. I'm now wishing I hadn't bought this tool, but now I can stumble on with my first build. Joe.


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## Curious-George (Aug 10, 2008)

mx_599 said:


> i have this tool and use it all the time. however, i agree with the others as well. since you have it, run it lightly. if the fork is machined nicely then it will just skim the surface. it won't hurt it.
> 
> this isn't any worse than people chasing threads excessively...which can over-cut threads.
> 
> mx


i dont see how ``over chasing`` could cut threads, it would just follow through like all the other times


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## Bikinfoolferlife (Feb 3, 2004)

Never used one, have never seen one. What other tools did you buy for the build? I like tools, but there are limits...


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## themanmonkey (Nov 1, 2005)

OK, it really depends on the factory prep on the fork. Generally the steerer-tube is just fine in diameter, it's the crown seat and steerer/crown interface that sometimes needs a little trimming. Sure I've just thrown on crown-races on forks without prepping, but if I question to quality of the fork or the prepping I mill that sucker.

Of the last 100 crown races I mounted I milled about 30% of them. I'd say road forks come milled better than sus forks as a general rule.


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## mx_599 (Dec 10, 2005)

Curious-George said:


> i dont see how ``over chasing`` could cut threads, it would just follow through like all the other times


not true. taps and dies can "re-shave" threads when there is no problem or distortion. i am just saying...but i wouldn't chase anything unless i knew there was a problem or i thought it was distorted from welding or something.

don't chase threads for the sake of chasing. nothing gained.

mx


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