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View Full Version : washer needed between prop and nut?


Joseph
03-29-2010, 02:06 PM
went to my brother in law's shop to have him help pull the prop on my 99 maristar and he sort of freaked when he noticed i didn't have a washer between the prop and nut. I'm a sort of leave it like you found it guy but he designs and builds firetrucks from scratch (blanchat manufacturing) so he found one and put it on. I came home later and went to the mastercraft bible (TT) and found that there isn't suppossed to be a washer. So the quick and dirty. Leave the washer? (but it's not stainless or brass and will prob rust off anyway) Replace it with ss or brass? or remove it? What will it hurt? (i'll have to give him a good reason) thanks guys in advance.

ahhudgins
03-29-2010, 02:12 PM
I've never had a washer on any of my Mastercrafts and I've never heard of them having one. I'm sure some of the techs will ring in on this one to confirm. But as you stated, a non-stainless steel washer is a NO-NO under water.

Kyle
03-29-2010, 02:16 PM
To remove or install a prop it only takes 5 minutes. I personally would remove the nut and remove the washer and install the nut back on WITHOUT a washer. You dont want the rust or any build up on the end of the prop shaft. You especially dont want to mix the different materials. Even if you let it rust off then there is a loose nut there.

You dont have to take the prop off and if it is tightened up the prop being pressed on is not going to be an issue bc you are not taking it off all of the way.

Spend 5 minutes and do it right so you dont have to spend 5 hours fixing new problems down the road, wishing the whole time that you took it off before the new issues happened.

Mastercraft Does Not put washers in between the prop and the nut.

thatsmrmastercraft
03-29-2010, 02:27 PM
I suppose since the prop does not spin on the shaft, there is no need for a thrust washer between the prop and the nut. I would still think that MC would have designed a washer to be installed to protect the back side of the prop from any galling from tightening the nut. But what do I know, I'm just a salesman. :confused:

EJ OJPROP
03-29-2010, 03:08 PM
No washer is needed. A good BRASS Ny Lock nut and SS cotter pin is all you need.

Joseph
03-29-2010, 09:12 PM
thanks. i'll be taking the washer off. Any tech answer about why a washer is not used or should not be used? i don't need as much tech talk as the "wax the bottom of your boat thread" but it is sort of interesting as to why or why not you need a washer. (can't believe i just wrote that. the weather really needs to warm up-lol)

ahhudgins
03-29-2010, 11:16 PM
I've changed many props in my life and have never boogered up any of them by not having a washer on them. That's about as technical as I can get. While you're under there taking the washer off, go ahead and wax the bottom to make it go faster!!:D

Shaun315
03-29-2010, 11:52 PM
thanks. i'll be taking the washer off. Any tech answer about why a washer is not used or should not be used? i don't need as much tech talk as the "wax the bottom of your boat thread" but it is sort of interesting as to why or why not you need a washer. (can't believe i just wrote that. the weather really needs to warm up-lol)

Aside from the mechanical reasons, brass+steel+electrolyte(water in this case) = galvanic reaction, should be enough of a reason to take it off.

MariStar-Man
03-30-2010, 01:13 AM
Aside from the mechanical reasons, brass+steel+electrolyte(water in this case) = galvanic reaction, should be enough of a reason to take it off.

That's exactly what I was thinking...

i guess I'll keep you on the payroll....lol!:D

Kyle
03-30-2010, 02:51 AM
It is installed without a washer because 1 there will be 3 different materials and you dont want to mix them and 2 your shaft is tapered. With a tapered shaft some props will slide further up the shaft than others. Some will not slide as far. This being the case washer size will change every time you switch props.

They just are not needed. Glad to see you are removing the washer and waxing the boat bottom so you can maximize your top end:D

erkoehler
03-30-2010, 08:00 AM
Never seen a washer used and we see some crazy stuff come through the shop!

Take the washer off!

east tx skier
03-30-2010, 09:54 AM
Just a heads up. For those of you who have nylock nuts holding your props in place, make sure you check them regularly. I had one work its way loose once and I have heard stories of that happening to other people as well. If you regularly remove your prop, you may want to replace that nylock nut every so often.

/using a castle nut now.

EJ OJPROP
03-30-2010, 10:14 AM
A castle nut instead of a Ny Lock? We replace a lot of those RH turning props that fall off shafts when the pin breaks and the castle nut falls off. Jus sayin....

thatsmrmastercraft
03-30-2010, 10:15 AM
That Nyloc nut is a one-time use fastener. When you install it, threads are cut through the nylon material and holds well. After it is removed, it is just another fastener. Actually, not as good as a plain nut as there are fewer metal threads to hold.

MariStar-Man
03-30-2010, 10:40 AM
I bought one of these the day I needed it to pull off the prop. I just checked my setup and theres a Nylock nut and a Silicon Bronze and Brass Cotter pin. (supposed to be stronger)

So Eric, Is it adviseable to change nylock nut whenever one changes the prop?

and Torque to app. 30lbs?

http://propull.com/index_files/ppf101_big.jpg

http://i180.photobucket.com/albums/x203/DocHoliday1964/1999%20Maristar/DSC01084.jpg

That Nyloc nut is a one-time use fastener. When you install it, threads are cut through the nylon material and holds well. After it is removed, it is just another fastener. Actually, not as good as a plain nut as there are fewer metal threads to hold.
I'm sure your correct MrMC, just curious what eric's thoughts are...

EJ OJPROP
03-30-2010, 10:58 AM
I usually do not replace the nut each time. Have done a lot of prop testing using the same ny lock nut. Would run the same ny lock nut in a race weekend on our outboard tunnel boats that would turn over 9,000 RPM. Guess I do not see the ny lock as a one time use thing. If the ny lock looks worn out, replace it. Even a used ny lock is much better, IMHO, than a castle nut that will back off with no pin. In over 20 years of doing this prop thing I have not seen a ny lock back off, plenty of castle nuts though.

Not sure on the silicone bronze and brass cotter pin....

piper_chuck
03-30-2010, 12:44 PM
My rule of thumb for nylock nuts is to replace them when I can turn them past the nylon by hand. I figure as long as they're still tight enough to require a wrench to thread them on that they're not going to come off on their own.

TMCNo1
03-30-2010, 03:10 PM
Depending on the application, s/s prop vs nibral prop, a new $4 Nyloc nut every time a nut is removed, is cheaper than a new replacement prop and the embarrassment of the tow back to the dock.

MariStar-Man
03-30-2010, 04:32 PM
>>Go here to see item<< (http://www.skidim.com/prodinfo.asp?number=NUTNYLBR3410)

Item Number : 2201

Unit Price: $9.50

"D.I.M. has a large selection of nuts, keys, and cotter pins in both brass and stainless steel. We recommend the nylock nut over the castle nut. If you have a Nautique with the castle nut and replace it with the nylock it will cover the hole for the cotter pin, but we have yet to hear of anyone losing a prop with the nylock nut (we know several that have lost them using the castle nut)."

Fits 1" or 1-1/8" shafts.


http://www.skidim.com/images/2201.jpg

TMCNo1
03-30-2010, 07:28 PM
I guess I need to buy some nuts and sell them.

TMCNo1
03-30-2010, 07:35 PM
I guess I need to buy some nuts and sell them.
Woah wait, I just need to sell my new 20 year old supply of new plain brass, polished brass, chromed brass, stainless and polished stainless Nyloc nuts,
56666

MariStar-Man
03-30-2010, 07:53 PM
Wow! With all the spare MC parts you have TMC#1, you could open a satellite MC Store...

Great organization. :)

thatsmrmastercraft
03-30-2010, 11:26 PM
I guess I need to buy some nuts and sell them.
Woah wait, I just need to sell my new 20 year old supply of new plain brass, polished brass, chromed brass, stainless and polished stainless Nyloc nuts,
56666

I hear if you buy that, a pristine boat comes along with the package.

east tx skier
03-31-2010, 12:03 AM
A castle nut instead of a Ny Lock? We replace a lot of those RH turning props that fall off shafts when the pin breaks and the castle nut falls off. Jus sayin....

Eric, I didn't seek it out. It came with the boat. So far, it has been much more successful at staying put than my nylock nut was. In either case, the cotter pin is the key element. Those loose props make an awful lot of noise in reverse. Thanks to the cotter pin, I didn't lose the prop in the lake when my nylock decided to take a break.

Reminds me, I need to spend $.30 on a new pin. :)

east tx skier
03-31-2010, 12:06 AM
I usually do not replace the nut each time. Have done a lot of prop testing using the same ny lock nut. Would run the same ny lock nut in a race weekend on our outboard tunnel boats that would turn over 9,000 RPM. Guess I do not see the ny lock as a one time use thing. If the ny lock looks worn out, replace it. Even a used ny lock is much better, IMHO, than a castle nut that will back off with no pin. In over 20 years of doing this prop thing I have not seen a ny lock back off, plenty of castle nuts though.

Not sure on the silicone bronze and brass cotter pin....

Mine definitely backed off and did not appear to be worn out. I'll definitely check my pin on my castle nut though. Easy enough to replace if need be. Nylock seemed like the right choice to me before I had that happen. I wasn't trying to say that a castle nut was superior by any means. Let's review the meat of my previous post:

Just a heads up. For those of you who have nylock nuts holding your props in place, make sure you check them regularly. I had one work its way loose once and I have heard stories of that happening to other people as well. If you regularly remove your prop, you may want to replace that nylock nut every so often.

I suppose there are plenty of things that could shear a cotter pin. So the advice is well taken. I was just reminding those with nylocks to check them because, in my experience, they can and do back off.

FrankSchwab
03-31-2010, 01:18 AM
In the aviation world, replacing Nylocs is standard operating procedure as far as I know - you never know how many times it's been removed/replaced, there's no way to create a standard measurement technique to know when one needs to be replaced, and they're cheap (most of them are small).

Of course, when a boat prop falls off, it tends to be a lot less of a crisis than when an aircraft prop (or aileron, or rudder, or wing, or...you get the idea) falls off.

/frank

rd1900
03-31-2010, 07:19 AM
Proper fastener performance is really a lot more complicated than simply choosing Nylock or Castle Nut. Every nut will come loose if it isn't tightened to the proper torque, which is quite hard to determine. Unless the threads have the correct stretch and compression load between the bearing surfaces of the nut and prop (in this case), the nut will always come loose. And too much stretch will deform the threads and make a weak joint.
The Nylock fastener is nice for vibration resistance in low load applications, but the nylon insert doesn't really do much to keep the nut tight.
Only torque will keep it tight, and as soon as the nut is a little loose is really isn't doing any work. And the cotter pin just keeps everything from falling apart, once the whole assembly is loose enough for the cotter pin to come into play the whole thing is a real mess.
And a washer is really just for load distribution, so it serves little purpose when it is the same size as the nut.
So you can really use any type nut you want if it is torqued properly, the cotter pin is just there to keep everything together if the nut becomes loose, and the Nylock nut is just a tiny bit of insurance if your torque is a tiny bit low.
On a similar note, the woodruff key in a non-splined shaft doesn't do any work either, it's the compression between the prop and shaft (provided by the torqued nut) that keeps the shaft and prop turning together.

east tx skier
03-31-2010, 11:18 AM
The torque is actually pretty heavy to get the castle nut on my shaft to a point where you can actually install the cotter pin.