The Ford Barn

V848 Ford · 10-30-2015, 11:55 PM

I micked the crank in my 255 block and can only find .ooo2 out of round so I think I will put it in the lathe and polish it. What is the correct grit to use?

40 Deluxe · 10-31-2015, 01:39 AM

Try crocus cloth.

flatheadmurre · 10-31-2015, 02:41 AM

If you dont have a belt polisher for the purpose make a clamp out of 2 pieces of hardwood.
That way you will polish it straight and flat.

34PKUP · 10-31-2015, 04:56 AM

Sounds like .0002" is within service limits.
Exactly how do you propose to polish only the high side of the journal and not touch the low side.
Suspect you will do more damage than any perceived correction by attempting to polish.

JWL · 10-31-2015, 06:28 AM

You can buy crank polishing belts from Goodson and others. But, unless you can offset the crank as it would be in a crank grinding machine it will be difficult to do a proper job.

GOSFAST · 10-31-2015, 06:53 AM

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You can use the method shown in the photo below. It is taken directly out of the Chevrolet "Power Manual". It uses the chosen paper cut in strips and a short length of rope. This method does NOT require "spinning" the crank!

It does work but takes some practice to get the "feel". If you "play" with some "600" grit paper you won't cause any damage or remove any material.

Thanks, Gary in N.Y.

P.S. We have a "dedicated" belt-style crank polisher, uses "240", "320", "400", or "600" grit (we rarely use the 600). I will also add .0002" (2 tenths) is a "non-issue", you will find more "error" than that in new brgs.

woodiewagon46 · 10-31-2015, 09:58 AM

I agree with 34PKUP, leave it alone. If you really don't know what your doing, you can cause more damage to the crank. .0002", I wouldn't do a thing.

HP Hunter · 10-31-2015, 10:20 AM

I polish all cranks before they get put into any motor.

Harry

flatheadmurre · 10-31-2015, 11:49 AM

If you can polish it correctly its an inprovement.
Done incorrectly it can result in a worse then before status.
A standard belt for a crankpolisher is supposed to be running highspeed and to corse for handpolishing in a lathe.
That woodpiece trick aint to bad in a lathe...many Scania truck cranks was finished that lowtech way in production

Its basicly the same idee as using a block for sanding you get a flat surface.

deuce_roadster · 10-31-2015, 12:46 PM

First off, how sure are you that the mic you are using is accurate to that degree. Second, it is within tolerance and you can only make it worse by accident so just leave it alone, you won't be making it any better.

Ross F-1 · 10-31-2015, 01:26 PM

I'd worry about getting all the abrasive and filings out of the oil passages afterwards. Leave it alone!

Bored&Stroked · 10-31-2015, 05:29 PM

Why don't you post a couple pictures of your journals? I'd like to see them - just to see what condition they are in. If they are good, don't screw with it.

If not, take it to a crank grinder and have them polish it the right way. Why take a chance with a method that is suspect at best . . . especially since you're probably buying a new set of bearings.

jake197000 · 10-31-2015, 07:04 PM

what gofast listed is fine way to do it.works great.

Karl Wolf · 10-31-2015, 08:13 PM

Quote:

Originally Posted by GOSFAST

You can use the method shown in the photo below. It is taken directly out of the Chevrolet "Power Manual". It uses the chosen paper cut in strips and a short length of rope. This method does NOT require "spinning" the crank!

It does work but takes some practice to get the "feel". If you "play" with some "600" grit paper you won't cause any damage or remove any material.

Thanks, Gary in N.Y.

P.S. We have a "dedicated" belt-style crank polisher, uses "240", "320", "400", or "600" grit (we rarely use the 600). I will also add .0002" (2 tenths) is a "non-issue", you will find more "error" than that in new brgs.

If you tear strips of crocus cloth to the width of the journal, place them on a 3 foot piece (or so) of gaff tape, you will have a long run of the crocus cloth.
Now, put the crank on end. Maybe with the flywheel or in a vise.

Walk around the crank while you pull the crocus strip from side to side.
I've done this lots of times and it works great... Don't forget the compressed air to clean your grit from oil passages.

Karl

Ronnie · 10-31-2015, 09:09 PM

If you really think that it needs a polish go down to the local machine shop and buy a crank polishing belt and take it home and use it as described and be done with it. The cost of the belt is less than a burger at McDonald's and 320 or 400 is all you need.Never mind the crocus cloth voodoo and all the rest here just get the belt they come in a 91" x 1" length or 72" or 64"as a common size cut it for the ease or operation clean it up well after u are done and you are done far from rocket science.

R

V848 Ford · 11-01-2015, 12:52 AM

Thaks for all the info. guys I am going to practice on a junk crank first. I have standerds for checking my micks out so i don't screw the crank up.

10-30-2015, 11:55 PM	#1
V848 Ford Member Join Date: Jul 2010 Posts: 99	correct grit for polishing crank I micked the crank in my 255 block and can only find .ooo2 out of round so I think I will put it in the lathe and polish it. What is the correct grit to use?

10-31-2015, 01:39 AM	#2
40 Deluxe Senior Member Join Date: May 2010 Location: now Kuna, Idaho Posts: 3,779	Re: correct grit for polishing crank Try crocus cloth.

10-31-2015, 02:41 AM	#3
flatheadmurre Senior Member Join Date: Apr 2015 Location: Sweden Posts: 3,045	Re: correct grit for polishing crank If you dont have a belt polisher for the purpose make a clamp out of 2 pieces of hardwood. That way you will polish it straight and flat.

10-31-2015, 04:56 AM	#4
34PKUP Senior Member Join Date: Feb 2011 Posts: 794	Re: correct grit for polishing crank Sounds like .0002" is within service limits. Exactly how do you propose to polish only the high side of the journal and not touch the low side. Suspect you will do more damage than any perceived correction by attempting to polish.

10-31-2015, 06:28 AM	#5
JWL Member Emeritus Join Date: May 2010 Location: Fitzgerald, Georgia Posts: 2,204	Re: correct grit for polishing crank You can buy crank polishing belts from Goodson and others. But, unless you can offset the crank as it would be in a crank grinding machine it will be difficult to do a proper job.

10-31-2015, 09:58 AM	#7
woodiewagon46 Senior Member Join Date: Jun 2012 Location: Long Island,NY Posts: 1,555	Re: correct grit for polishing crank I agree with 34PKUP, leave it alone. If you really don't know what your doing, you can cause more damage to the crank. .0002", I wouldn't do a thing.

10-31-2015, 10:20 AM	#8
HP Hunter Member Join Date: Jan 2011 Posts: 78	Re: correct grit for polishing crank I polish all cranks before they get put into any motor. Harry

10-31-2015, 11:49 AM	#9
flatheadmurre Senior Member Join Date: Apr 2015 Location: Sweden Posts: 3,045	Re: correct grit for polishing crank If you can polish it correctly its an inprovement. Done incorrectly it can result in a worse then before status. A standard belt for a crankpolisher is supposed to be running highspeed and to corse for handpolishing in a lathe. That woodpiece trick aint to bad in a lathe...many Scania truck cranks was finished that lowtech way in production Its basicly the same idee as using a block for sanding you get a flat surface.

10-31-2015, 12:46 PM	#10
deuce_roadster Senior Member Join Date: Oct 2011 Location: Shelton, WA Posts: 3,800	Re: correct grit for polishing crank First off, how sure are you that the mic you are using is accurate to that degree. Second, it is within tolerance and you can only make it worse by accident so just leave it alone, you won't be making it any better.

10-31-2015, 01:26 PM	#11
Ross F-1 Senior Member Join Date: Nov 2010 Location: NM Posts: 2,438	Re: correct grit for polishing crank I'd worry about getting all the abrasive and filings out of the oil passages afterwards. Leave it alone! __________________ '52 F-1, EAB flathead

10-31-2015, 05:29 PM	#12
Bored&Stroked Senior Member Join Date: Jan 2011 Location: Central Ohio Posts: 5,073	Re: correct grit for polishing crank Why don't you post a couple pictures of your journals? I'd like to see them - just to see what condition they are in. If they are good, don't screw with it. If not, take it to a crank grinder and have them polish it the right way. Why take a chance with a method that is suspect at best . . . especially since you're probably buying a new set of bearings.

10-31-2015, 07:04 PM	#13
jake197000 Senior Member Join Date: Sep 2010 Posts: 350	Re: correct grit for polishing crank what gofast listed is fine way to do it.works great.

10-31-2015, 09:09 PM	#15
Ronnie Senior Member Join Date: May 2010 Location: Canada Where it snows Posts: 2,058	Re: correct grit for polishing crank If you really think that it needs a polish go down to the local machine shop and buy a crank polishing belt and take it home and use it as described and be done with it. The cost of the belt is less than a burger at McDonald's and 320 or 400 is all you need.Never mind the crocus cloth voodoo and all the rest here just get the belt they come in a 91" x 1" length or 72" or 64"as a common size cut it for the ease or operation clean it up well after u are done and you are done far from rocket science. R

11-01-2015, 12:52 AM	#16
V848 Ford Member Join Date: Jul 2010 Posts: 99	Re: correct grit for polishing crank Thaks for all the info. guys I am going to practice on a junk crank first. I have standerds for checking my micks out so i don't screw the crank up.