Model Engine Maker
Help! => Specific Engine Help => Topic started by: awJCKDup on March 17, 2017, 10:45:14 PM
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Hi all, Ive been re-reading as much as I can about turning a one piece multi-journal crank. I see where a few guys have ground the journals with a tool post grinder or a substitute. My question is this: what are "acceptable" methods of finishing the crank if grinder is not available? also what grit stones? Any and all tips would be appreciated. I believe I am nearing the dreaded "Analysis Paralysis" with an some contributing "Puckeritis".
John
(http://i1189.photobucket.com/albums/z429/awJCKDup/100_4058_zpsjehqccf2.jpg)[/URL]
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Hmmm, crickets chirping :help:
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John--I've built about 25 engines, and all of my crankshaft journals have been turned using a 3/16" wide parting off tool. No grinding was involved. ---Brian
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No replies so i'll toss in my 2 cents worth. I turn everything to about .0005 over sized and then polish in the last half thou with 320 grit sand paper. Just cut a piece a little less than twice the width you need, fold it in half, and polish in the lathe to a smooth surface. This assumes a nice finish from the tooling.
That engine looks familiar.
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That is beautiful John. How far along is it?
-Bob
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I couldn't reply as I don't know enough. But I'm interested in finding out what you find out.
Sorry I'm no help.
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Brian thanks for the info.
Steve thanks, thats been my method on everything else I've built, none have been multi cylinder, so it wouldn't be too much trouble to make another crank. My feeling is If I get this made, I won't want to make another. Just trying to do it right the first time, and don't have a grinder. You've a good memory, I showed you pictures last year at NAMES.
Thanks Bob, that's an up to date pic. all internal block and head machining is done, the crank is roughed out, and the bell housing and adapter is made. Still planning on additional machining on the oil plan and I left tons of material on the valve covers, not sure what I will do there.
Zee, now we know. If Steve's have lasted, thats good enough for me, I know he's put a lot of time on his engines.
Thanks everyone
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(http://i770.photobucket.com/albums/xx349/stevehuckss396/V8Demon/DSCN1217s-1.jpg~original)
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John.......after seeing the picture of Steve's crankshaft, I hope you have the time to document the process of turning yours. Should be fascinating!
Jim
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Jim,
My old tool buddy said I was the biggest procrastinator that he knew, personally I think he was wrong, I think I'm just lazy. So while I will take some pictures, I would caution you not to get your hopes up. I suppose knowing ones limitations is a good thing, but I'll try.
John
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Well I gave it a shot, and I'm happy with the outcome. Here's some pic's, I was so busy frettin and puckerin, I didn't get many.
(http://i1189.photobucket.com/albums/z429/awJCKDup/20170322_093513_zpsyohsb8z4.jpg)[/URL]
(http://i1189.photobucket.com/albums/z429/awJCKDup/20170324_225733_zpsntbdk3kf.jpg)[/URL]
(http://i1189.photobucket.com/albums/z429/awJCKDup/20170325_183618_zpsg4vif6f5.jpg)[/URL]
(http://i1189.photobucket.com/albums/z429/awJCKDup/20170331_140946_zpsvmgbu936.jpg)[/URL]
Thanks for all the help
John
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That's a great lookin' crankshaft!! :praise2:
Pete
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John that crank looks great. Well done.
-Bob
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Thanks guys
John
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Impressed. ............. Very. :ThumbsUp: :)
Nick
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I was so busy frettin and puckerin
Apparently a very successful technique. ;D
I use it myself but generally don't get the great results like you did.
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Thanks Nick and Zee. Took a shot at the split bearing inserts yesterday, something I thought would be NON puckering......scrapped the first two, decided on a time out. Got them made today, still need alittle hand fitting.
John