lapping compound ?
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=9567
Printed Date: September-27-2024 at 8:27pm
Topic: lapping compound ?
Posted By: dans
Subject: lapping compound ?
Date Posted: February-05-2008 at 4:38am
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Please explain this lapping procedure for installing a prop.What lapping compound is good to use & were do you get it. Do I just put it on the shaft & spin the prop by hand for a bit without the key in place ? What does this do ? Allow the prop to go further up the shaft? Thanks , Dan. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1404&sort=&pagenum=1&yrstart=1981&yrend=198582 - 82 2001 |
Replies:
Posted By: 8122pbrainard
Date Posted: February-05-2008 at 7:16am
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Dan, Lapping compound is a abrasive mixed in with a light grease. It is ment to remove any high spots on the shaft and the prop taper so the taper fits or "seats" better. Your procedure is correct. The taper fit is really how power gets from the shaft to the prop. You can get it at a auto supply. I would get one of the finer grits. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: eric lavine
Date Posted: February-05-2008 at 10:33am
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after done lapping and when installing the nut i will put a small amount of grease or never sieze on the nut face that contacts the prop, it wont gall and will allow the nut to turn easier once it makes contact, ------------- "the things you own will start to own you" |
Posted By: 8122pbrainard
Date Posted: February-05-2008 at 11:08am
Dan, Yes, grease or never sieze on the nut and threads ONLY. NOT on the taper. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
eric lavine wrote:Posted By: dans
Date Posted: February-05-2008 at 11:15am
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Thanks for the advise. I guess I got lucky cause my 1 year old 542 popped off with two taps on a piece of wood against the prop. Two light taps on both sides off the back of the prop.Question - Can I reuse the key? It's 1 year old & the shaft put a line down it. It still goes in easy. Thanks, Dan ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1404&sort=&pagenum=1&yrstart=1981&yrend=198582 - 82 2001 |
Posted By: eric lavine
Date Posted: February-05-2008 at 11:44am
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yes you can re-use, the taper and the key hold the prop, i think i mentioned this once before that we would press gears onto a plan taper shaft with no keys at all on the shaft or the gear and these gears had thousands of horsepower going thru them, they were called: keyless tapers...you would have to see it to believe it but they relied on the taper to hold the gear on the shaft. the way we would remove them was with a hydrualic tool into the end of the shaft filling it with gear oil and running a bolt into the tool and the hydraulic pressure would blow the gear off. ------------- "the things you own will start to own you" |
Posted By: 8122pbrainard
Date Posted: February-05-2008 at 11:52am
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Dan, You can reuse the key. Remember that it is the taper that does all the work. The line in the key as well as you being able to remove the prop with "two light taps" on the prop tells me someone didn't put in on correctly! The reason prop pullers are made is because they are required to pop the prop off a well fit taper. You really want to get some lapping compound and lap on the new prop. After you have twisted the prop with the lapping compound several times, remove it, wipe it down and look for different color areas. These areas will be the high spots that the lapping compound is working on. Continue until the whole taper is almost even.
The taper is a great idea. The most common use of it is the drill chuck on the end of a electri drill or cordless. The chuck has a female taper and the drill a male. No keys or splines!! ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: 8122pbrainard
Date Posted: February-05-2008 at 12:17pm
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Dan, Who put the one year old 542 on your boat? Have you been spending too much time over on "the" site? If so, you need more time here on CCfan with all the tech nuts/gear heads. Just kidding, I do enjoy the2001 as well!! ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: eric lavine
Date Posted: February-05-2008 at 12:44pm
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in dans case if the key was absent the prop s would have spun on the shaft so i should say the key keeps the prop from turning on the shaft, but is the taper that holds it ------------- "the things you own will start to own you" |
Posted By: dans
Date Posted: February-05-2008 at 1:01pm
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I put it on last time & used the method of marking the shaft with a sharpie without the key installed. . It was on good and lined up over the mark. The nut was also on good & lined up with the cotter pin hole. It seemed on good & didn't wiggle even when busting it loose last night. I think the wood Hammer method just worked good with two well placed hammer blows. I will try the lapping compound next time & maybe it will get a tighter fit.Thanks Eric & Pete for your help. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1404&sort=&pagenum=1&yrstart=1981&yrend=198582 - 82 2001 |
Posted By: 79nautique
Date Posted: February-05-2008 at 1:15pm
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don't get excited about the lapping compound you really don't need to do it as long as when you tighten it down with the keyway in place and it doesn't cover the mark you made when the key was removed when you trial fitted the prop. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: eric lavine
Date Posted: February-05-2008 at 1:49pm
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how the f would you lap it in anyways? Ive never lapped one in, if i did though i know an idiot like me would fire the boat and hold the prop to lap it. again dont try that btw ------------- "the things you own will start to own you" |
Posted By: 8122pbrainard
Date Posted: February-05-2008 at 7:30pm
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Eric, It is a recommended procedure by the prop manufacturers!
Does the drill chuck fall out of the shops drill press spindle too? Lapping in the prop is just one of those little thinks that I'll bet 95% of people putting on props don't do. I will confess, that I do not do it unless I suspect a problem with the taper fit. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: anthonylizardi
Date Posted: February-05-2008 at 7:51pm
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I just put a new prop on my 87 and I have no idea what you guys are talking about. Let me recap my understanding.
I know I am suppose to put lapping compound on the shaft maybe the prop too so the prop will take the shape of the shaft taper. How you grind it? Put the prop and nut without the key and turn it by hand? I like Eric procedure, I need to find somebody willing to hold it.  Just kidding
And, I should do that to reduce the loss of power transfer? Did I get that right? I have seen lapping compound when resetting valve. Probably is the same procedure. |
Posted By: LaurelLakeSkier
Date Posted: February-05-2008 at 10:29pm
Yes.....you are doing the same thing to the prop and prop shaft as with the valve face and seat. That is to say lapping mates the two surfces together for maximum surface to surface contact. |
Posted By: anthonylizardi
Date Posted: February-06-2008 at 1:49am
| Thanks for the information. I guess I learned something new. I will do this to my prop. |