Fitting a prop sanity check

leaky

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This afternoon I have been getting ready to install my prop.

I read up a bit, fit it on minus the key, marked it, filed key, fit, removed, filed key, repeat, found key became loose on driveshaft right about when it fit the prop right. Deburred prop keyway, repeat with new key and was more careful...

Just thought I had a working key then realized not quite - slight chatter detected only when key is installed. Will be back to the file again.

But just now I discovered prop lapping:


Tomorrow will grab the blue stuff and lapping compound and will see what's what (then get back to filing I assume).

I have read 3 recommendations on coating the shaft prior to actual install - 1, nothing, a clean shaft 2 - thread sealant 3 - anti seize.. what do you guys think?

Then I have read about people actually using epoxy or 5200 on the threads - any opinions on that?

Torque on the nuts I am reading basically just horse #1 down (maybe 100 lbs but no need to torque it), recheck/horse in 10 minutes, horse #2 down, install cotter pin and call it a day?

Thanks in advance!
 

Diesel Jerry

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leaky

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If you put 5200 on the threads I will personally come and piss in your gas tank!

Haha I seriously thought that was just some idiot customer of yours and was laughing my ass off when I read that post you put up about it..

Then reading seaboard's article, I see where it came from - *HOWEVER* in his defense, he was NOT saying to just spread the shit all over your taper & prop rather he is saying to use it like you would loctite - on the threads. Similarly epoxy was referenced there and other places too.

Do you do anything to lock the threads or is your reccommendation on that basically just let the friction do it's job?
 

WoundUpMarine

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Diesel Jerry

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ArchHibb

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Install dry w/o anything on the taper. After proper lapping, the fit between prop, shaft, and key should be perfect. The interface between prop and taper is what transmits the torque, not the key which is only there in case the prop nut loosens. Adding neverseize or something will result in the soft metal key transmitting the torque which concentrates all the strain on the keyways - not good.
 

ARC

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I always thought a tape shaft works because of friction and compression . The key is just to keep it indexed. When set properly, if you remove the key and inspect it . There should be no sign of side loading. Using any lubricant would reduce friction and be counterproductive . The only place for lube is on the face of the prop where the nut is making contact. That allows for proper torque. If you want to put locktite on the threads it will not hurt anything. Hell, these days people put 5200 and everything including their garden salad, so sure put a dab on it so you sleep better.
 

leaky

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I have posted the procedure a couple of times. Today I am going to Lowe’s and Cabela’s after that I am open to a phone call if you wanted to talk the whole process out. As long you don’t mind a 5 and 8 year old in the background.
In short nothing on the threads. I go big nut first and tighten as much as I can with the application of common sense (ACS). This presses the prop onto the taper. Then remove the big nut and put on the little nut. Tighten as much as possible using ACS. Then the big nut again. Tighten as much as possible using ACS. I have never “torqued to spec” nor used a slug wrench. Up to 4 or 5 props per season for the last 10 years, not mentioning the ones I did with my dad from age 6 to 19. I have never had a prop come loose.

Thanks Jerry! - before posting I absolutely did search the forum and found one of your procedures :). It just didn't mention or dismiss the whole grease on the shaft & "loctite" on the threads thing so figured it's best to ask first.
 

leaky

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Very true. Draw 3 lines with a sharpie. Lapping compound available at any NAPA. No need to put anything on threads but double nut and pin.
A black or red sharpie works well as a replacement for dykem to check your lapping progress

Glad you guys mentioned that because the chain auto parts places open on a Sunday don't stock Prussian Blue. Sharpie it is.
 

Viexile

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If you put 5200 on the threads I will personally come and piss in your gas tank!
Since I can't "like" 15 times on a single post I'm quoting. I haven't touched 5200 in years. Jeeziz I hate that stuff. After refitting what - 10 boats - I've had some pretty fine things to say about prior owners and their use of 5200 OR silicone.
 

leaky

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Since I can't "like" 15 times on a single post I'm quoting. I haven't touched 5200 in years. Jeeziz I hate that stuff. After refitting what - 10 boats - I've had some pretty fine things to say about prior owners and their use of 5200 OR silicone.

I get the 5200 thing, though certain places I think it is warranted.

What do you dislike about silicone? I tend to reach for that when you just want a mild seal that won't pickup mold. Never had a problem with it in those applications.
 
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I have posted the procedure a couple of times. Today I am going to Lowe’s and Cabela’s after that I am open to a phone call if you wanted to talk the whole process out. As long you don’t mind a 5 and 8 year old in the background.
In short nothing on the threads. I go big nut first and tighten as much as I can with the application of common sense (ACS). This presses the prop onto the taper. Then remove the big nut and put on the little nut. Tighten as much as possible using ACS. Then the big nut again. Tighten as much as possible using ACS. I have never “torqued to spec” nor used a slug wrench. Up to 4 or 5 props per season for the last 10 years, not mentioning the ones I did with my dad from age 6 to 19. I have never had a prop come loose.
Other than the fitted props that are hydraulically pressed on using the SKF system, what DJ said is how we install propellers at the shipyard. Doesn't matter if it's behind a 6V92 or a locomotive engine hopped up on seawater aftercooling, this is how we do it. I've never seen any problems. Just that the wrenches get big.
How I install my stuff.
 
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Viexile

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Silicone is virtually irremovable, especially if you want to paint something. If you try to clean it off, then sand it, it just spreads it around. You can never tell if you got it all. A pissah when you're trying to use 2 part paints. Polysulfide above the waterline (for the most part), polyurethane below. I do use 4200, works fine. It's just 5200 will separate laminate trying to get it off.
 

leaky

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Silicone is virtually irremovable, especially if you want to paint something. If you try to clean it off, then sand it, it just spreads it around. You can never tell if you got it all. A pissah when you're trying to use 2 part paints. Polysulfide above the waterline (for the most part), polyurethane below. I do use 4200, works fine. It's just 5200 will separate laminate trying to get it off.

Ahh ok yes I get that about silicone, even though it comes apart absolutely is a bear that way. I bet you really love clear silicone :)
 
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