Crown race cutter issue fix and Scotchbrite coolness

I have learned most everything I share on this blog from others.  I read blogs, forums, talk to builders a bunch. Blogs and forums are great, but I learn the stuff nobody wants to write down by just talking with other builders.  There is definitely somewhat of a ‘secrecy code’ with some builders so they won’t share certain things but others could care less and love to share the tricks they’ve learned.  I don’t really remember half of what-came-from-where with the techniques and tips I offer here, but when I do remember I’ll do my best to quote my source so they get credit and not me.

Anyways, these two things are pretty simple, nothing big, but I just happened to really think they’re cool this last fork build.

I have Cyclus (economy framebuilder tool) fork crown race cutter from Ceeway.  My first recommendation is buy the best you can afford…otherwise you’ll be selling your less than ideal tooling very soon for the thing you should’ve bought in the first place.  The Cyclus is a nice blue-handled cutter, but there’s enough play in the inner diameter of the shaft that you can over-cut the crown and end up having the crown race slip right on with no effort. This is especially likely when cranking on the cutter like with a lugged fork crown.  You will also get a very very uneven and rough surface finish.  I know they sell a cutter with an inner cutter that may give better results, but I can’t verify that. Peter at Ceeway offered these pieces of advice that may help:

a) Use plenty of cutting oil.
b) File down the OD of the crown race so the cutter has to do minimal work. The cheaper Cyclus ones don’t have an inner cutting face, but even with it, it is best to give the cutter just the finishing to size work. Otherwise the cutter can end up tearing the metal and that would leave it undersize.
c) Even pressure. I know it’s hard when you’re pushing yourself. The design can be somewhat old fashioned with the threaded nut not being useful on most forks these days. You should find a quick release or something that will enable you to use the spring to provide the pressure.
d) obviously no cutting on chrome.

So, after I had undercut the crown race diameter so that i got a loose fit, I added some 50N silver to the crown real quick so not to overheat the crown/steerer braze, and tried using the spring supplied with the cutter (but usually only used with 1″ threaded steerer tubes) and slid on a 30mm seat collar to give some even tension to the cutter.  It worked flawlessly. So with doing this you can use a cheaper cutter I guess…but I’m still wishing I had a better cutter…or even better a lathe!

2 Responses

  1. I unwrapped my Cyclo race cutter today and scratched my head as I looked at the threaded 1 1/8th spring tensioner. Who uses threaded 1 1/8th steerers? I used one of my paragon tube blocks to hold the spring against the cutter and gave it a few turns before I realized it wasn’t cutting like I expected. After a little searching I came across your site and saw that you are using the same tool. My next step is to use the file a bit like you suggest to get the dimension closer to the finished size. Maybe 450 for the Park tool is a bargain.

    • For lugged crowns without a lathe it’s a total PITA. I think the Cyclus cutter that cuts both the face (down) and outside of race (inside of cutter) would work better (like the Park version), but filing to start the process will prolong cutter life/money and give a much smoother finish. I learned the hard way…

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