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Old 11-20-2019, 08:32 PM   #7
Joe K
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Join Date: Jul 2010
Location: Cow Hampshire
Posts: 4,175
Default Re: Proper crankshaft grinding

Quote:
Joe, I hope you don't get mad but I'm going to offer a little different perspective on what you have stated, -with the exception of your last paragraph which I think is true.
Not mad and it appears you have taken almost all I have said and added to it. THIS is the purpose of the board.

And it has been um, (gosh) 40 years since I went through my little trial by crankshaft.

I think back to "truing" the center in my 1906 Flather lathe and I realize I was using the flywheel flange for truing, so no skim cut required - but it did help the crankshaft straightener get a better bite and do a better job.

Generally my experience with engine mains mirrors yours - but there is this "theory" about grinding the minimal amount and to do so may require relocating the center. Now with "aftermarket cranks" fully available perhaps the need/desire is not so much?

I will admit to not doing engines every day (fortunately) and I have the ultimate respect for anyone who did - or does. Including that Knight Engineering of Pigeon Cove dude who brought me the bad news of a bent crank. He like most others in his trade did the best he could with what he was given.

And, yes, cranks can bend merely in sitting - I have one on the floor right now on its side which every day I pass and think I should do better to "keep 'er straight." But not to the tune of 0.015 like my original engine crank showed AFTER grinding. This was the product of a grinder who didn't give a $*it.

Maybe it was his bad day?

Joe K
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