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Old 13-03-2013, 07:37   #1
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Galling

Would anyone be willing to share their pictures of keel bolt galling? Before and after clean up would be nice?

We have read the threads on re-torquing keel bolts and we know what galling is, but we don't know what would be considered significant galling.

Below are pictures of a 3/4" stainless keel bolt from our Pearson 31-2. The top of the bolt is dinged up, but where the nut meets the bolt looks pretty good.

Is this type of visual inspection sufficient for detecting galling? (The zoom on my camera is way better than my eyesight).





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Old 13-03-2013, 21:50   #2
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Re: Galling

On the second picture the threads at the bottom look weak. Maybe camera angle. The top looks OK, but bashed up.
Is there room to recut the threads with a die, screw a nut onto the bottom. and put a second nut on top, with the good threads, in case the nut on the bottom does not hold.
I would use anti-seize putting them back on.

Glen
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Old 14-03-2013, 08:21   #3
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Re: Galling

The bottom threads do look a little thinner (see the close up below), but healthy enough for reuse, I hope.

I don't have a die set, but I'll clean up the dings on the bolt with a file, and to avoid using a possibly galled nut, I'll buy a new one.

Of more concern is what looks like a crack on the second thread up. Not sure what to do about that. Any suggestions?



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Old 14-03-2013, 15:29   #4
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Re: Galling

SS can do stress corrosion cracking.
If just one, maybe ok, how many bolts, are there redundancies built-in?
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Old 14-03-2013, 15:41   #5
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Re: Galling

Sort of looks like a crack in the last set of pix just above the 2nd thread. I would clean it up with a wire brush/wheel and maybe do a die test. If not a crack then you could add a couple of washers to get up a bit so the nut sits in clean full threads. I never have liked stainless for keel bolts I would rather use plain old steel. Stainless suffers from pit corrosion as well as stress corrosion.
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Old 14-03-2013, 15:59   #6
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Re: Galling

If that is a crack and you don't want to replace the keel bolts, then I would move the nut further down, so less or thinner washers.

I would check every bolt with a die-test and video feed to a display (can use Skype for that nowadays) to enhance the image so you are really sure that no more cracks exist.
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Old 14-03-2013, 19:29   #7
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Re: Galling

Why did you have to take your keel bolts off?
Is the gray stuff on the bottom melted lead?

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Old 14-03-2013, 19:36   #8
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Re: Galling

I would personally get a piece of hardwood and give the top a smack with a hammer to see if the crack got bigger or the bolt snapped.. Had too many stainless fitting break on me from rotting inside out to take chances with keel bolts. Better to change them all than loose the boat.. The joys of boating LOL
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Old 14-03-2013, 20:22   #9
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Re: Galling

Quote:
Originally Posted by GlenM View Post
Why did you have to take your keel bolts off?
Is the gray stuff on the bottom melted lead?

Glen
Why, indeed? I've been thinking I should have gone the route of blissful ignorance.

There is some cracking along the keel hull joint and seawater was getting into the bilge. So, we are beginning the process of removing and re-torquing the keel bolts one at a time before sealing the keel.

That is bedding compound, maybe life calk, not lead. I will be cleaning up the bolts tomorrow to get a better look.

I was going to chisel some of the fiberglass out from around the bolt (1/4" x 1/2" down) in order to get bedding coumpound down around the bolt. If it is a crack, I could remove 1/4" of fiberglass from under the stainless plate to get below the crack.

I will definitely close my eyes and give it a good rap with a cudgel.

Can I run skype through the camera on my smart phone?

There are 10 keel bolts, six 3/4" and four 1". If the others bolts look good, I would be tempted to drop the nut down a little bit like Jedi suggested and pretended it never happened.
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Old 05-04-2013, 03:40   #10
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Re: Galling

I have a dye penetration kit on back order. In the mean time, I went over the bolt with a brass brush and took 100 pics from every angle. Couldn't see the crack. (I used a steel brush to get the last bit of corrosion seen in picture 1.)

The second picture shows more dinging on the upper part of the bolt.

I can screw the new nut up and down by hand most of the way. There are a few spots were I needed a little help from a wrench.

Moving forward.

I found a split die for thread repair from Murray Tools that I'll use to clean the threads. The split allows you start by placing the die on a section with good thread so you don't end up cross threading.

The specs from Pearson for 3/4" bolts is 125ftlbs. Everyone seems to recommend TefGel as a lube and to prevent corrosion. The problem is, I cannot bring myself to adjust the torque by a factor of 0.45 to account for the lubrication. This would result in a torque of 56ftlb. I'm afraid my keel will fall off!

(An experience marine mechanic told me I didn't need to adjust the torque. )

Question: Is SAE 20 oil enough to prevent galling when I torque the bolt????

I would then treat the bolts with marine grease annually to prevent corossion.






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Old 05-04-2013, 04:59   #11
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Re: Galling

Quote:
Originally Posted by Neo View Post
I have a dye penetration kit on back order. In the mean time, I went over the bolt with a brass brush and took 100 pics from every angle. Couldn't see the crack. (I used a steel brush to get the last bit of corrosion seen in picture 1.)

The second picture shows more dinging on the upper part of the bolt.

I can screw the new nut up and down by hand most of the way. There are a few spots were I needed a little help from a wrench.

Moving forward.

I found a split die for thread repair from Murray Tools that I'll use to clean the threads. The split allows you start by placing the die on a section with good thread so you don't end up cross threading.

The specs from Pearson for 3/4" bolts is 125ftlbs. Everyone seems to recommend TefGel as a lube and to prevent corrosion. The problem is, I cannot bring myself to adjust the torque by a factor of 0.45 to account for the lubrication. This would result in a torque of 56ftlb. I'm afraid my keel will fall off!

(An experience marine mechanic told me I didn't need to adjust the torque. )

Question: Is SAE 20 oil enough to prevent galling when I torque the bolt????

I would then treat the bolts with marine grease annually to prevent corossion.






You might consider re-passavating them. The wire brush will leave behind residue which will eventually rust. Citric acid works but I prefer Spotless Stainless.
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Old 05-04-2013, 05:02   #12
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Re: Galling

Both 3M and Fastenal recommend PTFE as lubricant when installing. I reckon a SAE oil could be okay if it is paraffin based.
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Old 05-04-2013, 06:10   #13
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Re: Galling

Quote:
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Both 3M and Fastenal recommend PTFE as lubricant when installing. I reckon a SAE oil could be okay if it is paraffin based.
Was PTFE around back in 1987 when my boat was manufactured? I'd like to know what they used. I'm thinking that 125ftlb might not be enough to seriously gall stainless, considering I couldn't see any galling on this bolt. Or maybe they used oil which was enough to prevent it.
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Old 05-04-2013, 06:21   #14
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Re: Galling

Quote:
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Was PTFE around back in 1987 when my boat was manufactured? I'd like to know what they used. I'm thinking that 125ftlb might not be enough to seriously gall stainless, considering I couldn't see any galling on this bolt. Or maybe they used oil which was enough to prevent it.
Indeed it was around at that time. 1987 isn't that long ago. Just use Teflon in a rattle can if you don't want to bother with the recommendations.
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Old 05-04-2013, 06:46   #15
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The torque adjustment for lubricationshould be applied to the torques published for just the type of metal of the DRY and CLEAN fastener. NOT to a torque spec from a boat manufacturer, who might or might not already have adjusted for an unknown lubricant.
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