Resurfacing a Flywheel on a Mill???

Maglin

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I'm looking to resurface a few flywheels and am wanting to do it on my RF-45 clone mill. I don't have a rotary table so I'm planning on mounting the flywheel on some 1-2-3 blocks and fasten to the table with a stud and use some jacks on the perimiter to support the edges of the flywheel. Going to have to use both hand cranks and try to get a decent circle.

I'm debating on using either a grinding cup in a arbor or a 90* face mill to do the job. I also have to machine a step for the pressure plate. I know machine shops use a grinder and some even use a brake lathe. I have to purchase either tool so I'm wondering what would give the best results w/o a rotary table? I would think the grinding cup will cause less vibrations/chatter but I've never used a grinding stone in this fashion.

So which one is probably going to be the best route?
 
I hate to sound negative on your idea, but I believe that you will be disappointed. The parallelism required to run smoothly is pretty close, on the order of 0.0020 or less out of parallel. And that is measured from the mounting hub, not the backside out near the edge, which sound like where you plan on using the blocks. I don't think I could do it satisfactorily by hand interpolating a circle. I'm not familiar with your mill, but I'd consider building an arbor and using it like a lathe, and mount a facing tool in a vise or clamped to the table. That puts a lot of load on the spindle bearings, so I'm not too crazy about that idea either, really.
 
David Utidjian link=topic=2368.msg15909#msg15909 date=1307410768 said:
Please, do not attempt to mount a heavy flywheel in your mills R8 collet. That mill will not spin slow enough for the correct SFM and it could really get deadly if the flywheel comes loose.

-DU-

I retract my idea in totality, after a bit of thought, and David's thoughts. It was a bad idea. I must have been thinking about a bigger mill.
 
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Thank you for your input. The main reason it's costs savings it was cause most machine shops don't make the step the correct height. Mine has to be .609-.612" which isn't much room for error. I didn't think about the wheel blowing up. Yeah that would suck. I also have a bridgeport but the Y ways have a little damage and from center of travel to extreme travel on the Y it's almost .003" height difference. I plan to rescrape them in the future but I was hoping I could get it done at home. I can't guarantee parrallism on a arbor made on the lathe to better support the hub surface of the flywheel and thus why I was thinking about using 1-2-3 blocks.

The flywheel I need to do now is for a 2.0L 4 cyl and is small but was pretty expensive and has a few hard spots that a flycutter would probably have a hard time with. I guess I'll just look for a good machine shop and measure the step height before payment to ensure it's proper. I could then have it Blanchard ground for a ensured quality job. Cutting it on the lathe isn't something I wanted as I wanted the cutting marks perpendicular to the clutch surface for proper break-in. Guess after you spend $5K+ on a motor you shouldn't skimp on the small things like the flywheel resurfacing.

Again thank you for the reply's. As I get older safety is starting to become more important so I can be with my kids longer in this world and didn't even consider the grinding cup exploding.

Jeremiah
 
Mayhem link=topic=2368.msg16194#msg16194 date=1307855935 said:
David - any special considerations for skimming a brake disc on a lathe?

Sorry for hi-jacking the post

Problems with skimming a disc on a lathe is that they often have hard spots. You could overcome this with carbide tooling, of course.

Interestingly, I've discovered that prices on brake rotors have come down dramatically in the past 20 years. I bought a new set for my 1998 Dodge Dakota last year for $32 apiece. Obviously, they are going to be made in Asia or Mexico for that price but they are better than thin ones done on a lathe, even if you can do a perfect job.

I don't like to have rotors recut anyway since they seldom last as long as new ones due to the heat involved. Most shops get something like $20 apiece to turn them so you are approaching replacement value as well.

So I would say that it can be done on a lathe but for the lower prices nowadays, it's become unnecessary.
 
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