How critical is the flatness of the magnet retainers? I am useing a dial gauge and can get the middle of the plates within .005, but when I go to either the top or bottom of the retainers, I get less or more clearance than in the middle, up to .010 difference. I have tryed tapping the retainners with a brass hammer and this helps somewhat, but they are still not as flat as I would like, or am I beeing too picky? Is this clearance a big factor in getting a good one flip starter? G..

I usually go by the high points of the plates.

I don't think .005 difference will cause a problem. The important thing is that the magnets be close to the same clearance all the way around and that the closest is not less then .025 from the coils.
Norm

George,

If you are within .010" quit fooling with it. It is going to work fine!

Royce

The quality enigma :

Perfection is the enemy of Good Enough and Good Enough … Isn’t.

Somewhere in between lies reality.

Be_Zero_Be

So what happens if you are closer than .025 to the coils, assuming they don't contact each other? This stuff is all new to me and I want to get it right. George..

The .025 is a safety measure. If you are closer, they could make contact due to vibration or expansion of parts. If they do make contact, you will experience the "BIG BANG". The "BIG BANG" can cause something to break. This could be something as small as damage to the magneto to as large as a broken crankshaft, transmission cover and block or axle, driveshaft, differential. Moving parts don't like an abrupt stop! Something will break.
Norm