Drilling flywheel for 10" clutch

[Yoyodyne]

Originally Posted by JWL

I would do it on the CNC mill or the vertical mill with the digital read-out using X and Y coordinates. Almost any shop could do that by establishing "zero" off the crankshaft register counterbore. The drilling and tapping and counter-drilling should be done perpendicular to the clutch face. My biggest problem would be finding the coordinate measurements that I worked out several years ago and have not used for at least 5 years.

Any modern machine shop should be able to do this. The problem may be that they don't recognize the bolt pattern. I remember long ago when i was long on ambition and short on experience someone brought me a truck flywheel to put an 11" PP pattern on. After hours of stepping off existing holes and making measurements and running the calculator I tumbled to the fact that the Long PP pattern is a standard pattern with a few holes missing. IIRC, it's either an evenly spaced 12 hole or 15 hole pattern with only 6 holes used, which makes it an easy job using jig borer coordinates, either directly from a modern DRO on a mill, or from a Machinists Handbook. Call every machine shop near you and ask if they can drill holes in a flywheel using X and Y coordinates, if one says yes take the wheel and PP to them with this thread printed out. Automotive shops often aren't equipped for this, but every job shop is.

[malpais]

Found a guy locally that can and has done thr drilling. He's list the coordinates and says he'll drill it when he refigures them. We'll see. Thanks for the help.

Gordon.