Had to modify a cassette lockring tool in a CNC milling machine

When racing started up again recently, it dawned on me that if I crashed my only road bike, a 2016 Roubaix, I might possibly have no road bike for months due to pandemic-related shortages.

I got lucky and a couple weeks later, got my hands on a Specialized Tarmac SL7 Comp with SRAM Rival AXS. I got lucky again soon after and scored a pair of Enve Foundation 65 wheels with an XDR rear hub body to fit the SRAM 12-speed cassette. Enve direct was showing 2022 shipping timeframes, so when BikeTiresDirect had one of these in stock, I jumped on it.

Everything went smoothly up until I had to move the rear rotor from the stock wheel to the Enve. The rotor is a centerlock that uses a cassette lockring tool. I had the tool, but its thru-hole was too small to clear the axle, even with the end cap removed. I could remove the entire axle and reinstall it later, but not wanting to risk damaging it, I decided to modify the $10 Park lockring tool instead.

Pictured above is the rear hub, disc, and lockring.

Pictured above is the lockring tool clamped in a vise in one of my CNC mills (Haas UMC-500 5-axis). As you can see, the hollowed out portion of the tool isn’t deep enough to clear the axle.

A quick probing routine (about 15 seconds) located the center of the bore.

Programming the helical toolpath in CAD/CAM software and running it took less than 10 minutes.

The finished product…

A zoomed out view of the interior of the machine.

Pictured above is another view of the finished product.

It fits! The axle measured right around 3/4". I machined the bore of the tool to 0.7650". Give or take 0.0002".

And here she is, in all her glory.

Still need to figure out my preferred bar height, then chop the steer tube. Also need to install my Enve SES Aero Road bars, but those will require a brake bleed due to internal hose routing.


$12 aus. :stuck_out_tongue_winking_eye: Not as much fun though.

I actually ordered one of those as well as a spare rotor, but didn’t want to wait til Wednesday. :laughing:

Tomorrow’s a national holiday in the states and I’m taking it out for the maiden voyage!

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Many many years ago, I pulled my RD on my steel bike into the spokes, stripping the RD mounting threads on a non-replaceable hanger. Had access to a machine shop those days (no CNC though). Drilled the hanger, machined an adapter, drilled the derailleur top pivot and tapped the hole, thinned the head of a new mounting bolt, and net result was the only RD to bolt from the inside out. Worked like a charm for years. Still have the bike, but as a fixie, so no more weird hanger.

It’s interesting you have a 5 axis mill but no lathe. I have a lathe, but no 5 axis mill. At least not one that works.


Why is Specialized doing this? Are they selling a “specialized” tool for this? This seems to be a pretty odd thing to do, but someone is doing it.

The other thread where I saw something like this was a Scott MTB, so I’m left befuddled.

That was my bike. The Syncros (Scott in-house) wheels that came with the bike have 6 bolt discs. It’s my carbon hoops with DT Swiss 240s hubs that require a different lockring for the front wheel.
As axles get bigger it’s inevitable.

Not sure if it’s Specialized or SRAM who decided to do this.

Park does make this now:

Not the best camera angle but my guess is the thru-bore is greater than .750".