Hi Folks -
I've got a 2001 Sportsmobile with a Quigley conversion. It was time to replace the front rotors so I gave Sportsmobile a call which led to a call to Quigley to get the details. According to Quigley, my conversion uses rotors spec'd for a 1986 Chevy K30. But
they must be turned/milled on the interior to make room for the ABS sensor mounted on the drive shaft housing.
Quigley is kind enough to offer the modified rotors for approximately $145 per rotor plus shipping charges. Therefore, $300 and some change for the two rotors. Stock rotors can be found for around $50 a piece.
I did a bit of searching for more information about the modification required and came across the following threads:
SMB 4WD Parts Reference Thread
Quigley 4x4 Front Brake reference
With this specific post containing information on the material that needs to be removed:
Brake Upgrade for Quigley 4X4
Now with some better understanding of what was needed and with access to a CNC machine shop, I decided to tackle the job of milling the rotors myself.
I began by removing one of my rotors so that I could verify the sizing and previous milling that had been done. It matched the information from diagram in the post above.
Made a quick run to the local O'Reilly auto supply store and purchased a pair of these which matched the old pair:
BrakeBest Select Brake Rotor
Part # 5048RGS Line: BBR
To use our CNC mill required me to generate the CAM for running the machine. I measured one of the new rotors and modeled it in my CAD/CAM app Fusion 360. The interior ledge that requires milling isn't a continuous radius. But I modeled it as if it was continuous as it would be fine milling as if it was.
Here's the sketch profile of the material that needs to be removed:
And here is a render of the rotor with the ledge on the inside:
Next up was creating the CAM operations to remove the material. As I would be using a mill and not a lathe, my operations were picked for that machine. I created three operations:
- Pocket - Clear main portion of ledge
- Pencil - Clean interior fillet of ledge
- 2D Chamfer - Clean edges
Finally it was time to machine the rotor. I mounted it inside of our Haas VF2 SS mill, set the home position, then fed the machine the G-Code generated by Fusion 360.
And here it is being milled:
To finally produce the machined rotor:
And, of course, a shot on the vehicle:
If you made it this far, thanks for looking. And I hope there's helpful info in here for others.