This is what.....
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=49454
Printed Date: April-27-2024 at 8:48pm
Topic: This is what.....
Posted By: 8122pbrainard
Subject: This is what.....
Date Posted: November-27-2020 at 12:05pm
happens when the marketing department doesn't involve the engineering department when they make a technical video. Do you use a adjustable wrench as a hammer?   https://acmemarine.com/blogs/resources/how-to-install-an-acme-prop" rel="nofollow - How to install an ACME prop – ACME Marine  Back yard hacking?------------- /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 < |
Replies:
Posted By: Fl Inboards
Date Posted: November-27-2020 at 1:40pm
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Adjustable wrenches to be used as hammer only while Standing under boat on lift!! ------------- Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise. 1993 Shamrock "fat" 20. 2008 Nautique 196 5.0 |
Posted By: Jonny Quest
Date Posted: November-27-2020 at 1:40pm
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Everyone knows that you use Vice-Grips and not an adjustable wrench for that. The locking mechanism on the Vice-Grips is a much better hammer. What a hack-job.
------------- Current 2003 Ski Nautique 206 Limited Previous 2001 Ski Nautique Open Bow 1994 Ski Nautique Open Bow Aqua skiing, ergo sum |
Posted By: lewy2001
Date Posted: November-27-2020 at 6:57pm
Ajustable wrench = Shifting spanner downunder or more commonly shortened to "shifter"  Can be used as a hammer when changing the prop on a lift or like I have seen CCF members do while still in the water at GL.  ------------- If you're going through hell, keep going http://www.correctcraftfan.com/diaries/details.asp?ID=2999" rel="nofollow - 89 Ski <a href="http://www.correctcraftfan.com/diaries/details.asp?ID=5685" ta |
Posted By: Gary S
Date Posted: November-27-2020 at 7:17pm
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You can bet the GL crew would be bending their props and lining up to have her loosen their nuts on their shafts as well
------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: KENO
Date Posted: November-27-2020 at 10:57pm
It seems like if you looked around a little at the Acme page you linked with the video on it, you'd find their "traditional weekend saver kit" that the girl in the video is using. Here's a link in case you can't find it http://acmemarine.com/products/acme-traditional-weekend-saver-kit" rel="nofollow - link It comes with the adjustable wrench as part of the kit. Maybe the kit was put together by the marketing department or maybe one of the secretaries..............or maybe by their engineering department. I think they know what a hammer is, since the "harmonic weekend saver kit." comes with an adjustable wrench and a hammer.to whack that harmonic prop knocker with unlike the "traditional weekend saver kit" You can call it backyard hacking, they probably call it something else like tested and approved by their engineering department. I know, I know..............they don't meet Pete's standards, but then again they don't quite follow their own written instructions either in the video. Any well equipped backyard hack knows there are an assortment of multipurpose wrenches like in the link below http://www.google.com/search?q=hammer+head+adjustable+wrench&sxsrf=ALeKk01Hk7AZALnWaJC_gI_5yx49_iWJqA:1606536343619&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiJ0dGgrqTtAhUlSTABHQDDAC0Q_AUoAnoECAYQBA&biw=1536&bih=722&dpr=1.25" rel="nofollow - link as for me................I'd probably just find a rock to smack it with
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8122pbrainard wrote:Posted By: 8122pbrainard
Date Posted: November-28-2020 at 6:12am
Ken, Thanks. Your demeanour is always a great start to my day. ------------- /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: swilliams
Date Posted: November-28-2020 at 6:45am
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She probably dropped the hammer in the water! I know I’ve got tools laying on the lake bottom. ------------- 1976 Martinique,350 Omc. 1975 Glastron/Carlson CV16,115 Merc. |
Posted By: KENO
Date Posted: November-28-2020 at 6:46am
Your demeanor is always just .................well never mind
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Posted By: DVskier
Date Posted: November-28-2020 at 3:58pm
| This is crazy! Acme used to have a write up on properly lapping the new prop to the shaft, I can’t believe they didn’t mention lapping. Also inscribing a line on the shaft to ensure prop is slid as far forward as possible. Good thing the video was for wakeboarders. Who cares if their props vibrate? |
Posted By: Duane in Indy
Date Posted: November-30-2020 at 9:16am
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OK, opening the can of worms. With todays CNC equipment and the accuracy of the equipment, I see no reason to waste time lapping the prop. If the shaft and the prop are manufactured on CNC equipment then the tapers have to be the same. The prop is programmed with the starting diameter and the finish diameter along with the starting and finish lengths. The shaft is given the same dimensions. If the machinery is accurate then the two have to be the same. (easily within .0005 inch) In the old days the lathe was set up with a taper attachment and could vary a fair amount. Then the prop was either bored with a taper attachment or reamed with a taper reamer. Those methods required extra work to get them to match. Pete (cause I know you will be first to oppose this) how is the drill chuck on a drill press or lathe tailstock held in?? With an unlapped Morse Taper. Just my $.02 cause I worked in aerospace machining since late '60's ------------- Keep it as original as YOU want it 1978 Mustang (modified) |
Posted By: DVskier
Date Posted: November-30-2020 at 2:26pm
| I stand corrected. My apologies Duane. This is the first I’ve heard of manufacturing tolerances being so tightly controlled. |
Posted By: Fl Inboards
Date Posted: December-01-2020 at 4:37pm
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Having run into this before on lapping props to shaft taper. Reminder shaft builder is not same machine shop as prop builder. machine Tools do differ from shop to shop. That was one of the things that was better constant when the prop manufacturer is the same shop as the shaft manufacturer. My problem is sure as heck i lap a prop and second run down the slalom course i hit a turtle and bend a blade...not worth the effort! ------------- Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise. 1993 Shamrock "fat" 20. 2008 Nautique 196 5.0 |
Posted By: Kristof
Date Posted: December-01-2020 at 5:26pm
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On my third ACME prop on my boat... Never lapped one, just put it on and go. Never had any problems or vibrations worth mentionning...
------------- - Gun control means: using BOTH hands! - Money doesn't make one happy, but when it rains cats and dogs, it's still better to cry in a Porsche than on a bicycle... |
Posted By: Duane in Indy
Date Posted: December-01-2020 at 6:37pm
Machine tools do vary, agreed. BUT CNC machines don't vary. Blue print dimensions for the taper are the same no matter whether for the prop or the shaft. All manufacturers are held to the same dimensions Machine tools are no longer the norm Doubt that the factory boat builders ever lap. Waste of their time. We quit lapping surfaces in the '80's. Lap if you care to. ------------- Keep it as original as YOU want it 1978 Mustang (modified) |
Posted By: 8122pbrainard
Date Posted: December-01-2020 at 6:49pm
Dave, I don't feel your apology is needed because I think Duane is missing an important issue. Just as Jody mentioned, all machining isn't the "perfect" CNC standards he has mentioned especially when you match old to new or even new to new from different sources. The old to new comes to play since there are many out there upgrading to the newer CNC props on older boats with older prop shafts. Then I've found the new to new doesn't always work ether. In recent years, I've done 4 double taper prop shafts 3 ARE's and 1 GP. All tapers were slightly off and required lapping. I was surprised that even from the same manufacturer the tappered bore couplings at the trans end didn't match the tapered shafts. The props I've done all need lapping no matter CNC or old cast hand worked. LAP your props people. Duane, How many props have you installed and have you checked there tappers?
------------- /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: Duane in Indy
Date Posted: December-01-2020 at 7:08pm
Pete, If you spent more time reading my posts thoroughly instead of just picking things apart then you would have noticed what I initially said. You ask how many I have lapped? Don't need to cause I know they are now machined to exacting standards. I know my field of expertise. You need to study more on modern machine practices and then you would understand what I am trying to tell you. I also stated "lap if you want" but you are wasting time. We all have our fields. Mine was working in tolerances that occasionally were + or - .000050. Yes, 50 millions of an inch. That is 1/2 of a .0001, one ten thousand of inch. I don't know squat about Fluid Dynamics like you do but I know CNC machining. Thanks and have a good evening End of discussion. ------------- Keep it as original as YOU want it 1978 Mustang (modified) |
Posted By: Hollywood
Date Posted: December-01-2020 at 7:50pm
| Lapping a prop is like winterizing with -100F antifreeze |
Posted By: 75 Tique
Date Posted: December-01-2020 at 8:57pm
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or having an aneurysm because someone ties up their boat using the lifting ring because it is a lateral vs a vertical load. ------------- _____________ “So, how was your weekend?” “Well, let me see…sun burn, stiff neck, screwed up back, assorted aches and pains….yup, my weekend was great, thanks for asking.” |
Posted By: 8122pbrainard
Date Posted: December-02-2020 at 6:17am
Duane, Sorry you feel I haven't read your comments, but I ensure you I have. I ask you to read the context of this thread again and undersatnd what it's about. The lapping is about what's out there concerning prop and shaft tapers and not what can be done with CNC machining. It's a suggestion for best practices I and as Jody mentions encourage. Jody has probably changed more props than I ever will in my life. Acme propeller who I'd say makes the most CNC props also states: "To help ensure vibration free operation, the propeller must be properly mated to the shaft taper" "The tapers of the shaft and propeller should be in contact over at least 75% of their surface area to transmit power effectively and without undue stress" " If tapers are not in proper contact, but tapers ARE to the same speccification. a proper lapping compound can be used to seat the propeller to the shaft taper" Have you heard about CC's problem with breaking prop shafts on the big G boat? I have a friend with the problem who's gone through I believe 5 or 6 shafts. CC did try several different shaft alloys without success but then the theory of improper taper contact came up. This to me was logical because his shaft breakage was in the middle of the taper. The last attempt to correct the breakage included lapping the prop to the taper and so far it's worked since the early summer. Also of concern of mine is the surface finish of the CNC bores I've seen. I'm certainly not the expert I believe you are but at best, I'd say it's no better than about a 352 RMS. To me, that surface finish sure can't help the contact area. I appreciate your comments on CNC machining and do respect your machining knowledge. ------------- /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: Kristof
Date Posted: December-02-2020 at 6:23am
and ------------- - Gun control means: using BOTH hands! - Money doesn't make one happy, but when it rains cats and dogs, it's still better to cry in a Porsche than on a bicycle... |
Posted By: KENO
Date Posted: December-02-2020 at 6:25am
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I think the original intent of this thread was so that somebody could call the Acme people backyard hacks
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Posted By: 8122pbrainard
Date Posted: December-02-2020 at 6:34am
But then the context changed.
------------- /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: KENO
Date Posted: December-02-2020 at 6:44am
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So like with most things today, there's more than one way to install your prop, Why not just let this whole topic die, it's been covered multiple times here on CCF already..
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Posted By: Morfoot
Date Posted: December-02-2020 at 7:49am
....and it's only Dec 2! It'sGonna be a long winters. ...........Lap! 
------------- "Morfoot; He can ski. He can wakeboard.He can cook chicken.He can create his own self-named beverage, & can also apparently fly. A man of many talents."72 Mustang "Kermit",88 SN Miss Scarlett, 99 SN "Sherman" |
Posted By: wayoutthere
Date Posted: December-10-2020 at 10:59pm
| The wrench pliers pin nut and prop can all go the bottom, what the hell did i tell you about wearing that ring in the water dammit |
Posted By: Gary S
Date Posted: December-11-2020 at 7:29am
I thought the main problem was finally narrowed down to the keyway being cut and extending out further than the propeller hub ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: DVskier
Date Posted: December-11-2020 at 10:05am
| Who knows? It is unlikely that Correct Craft will ever divulge what really was going on with the prop shafts snapping. Good riddance I say! |
Posted By: 8122pbrainard
Date Posted: December-11-2020 at 11:33am
In this case the theory that worked this summer was lapping. I've mentioned before that I believe 100% of the torque can be transmitted via tha taper and Acme says 70% goes through the taper. There are many examples where tapers are used only. I remember Eric saying that some of the internals in transmissions are taper only. So, in this case of the G braking shafts a fully lapped and seated prop has worked.
------------- /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: Gary S
Date Posted: December-11-2020 at 12:30pm
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I'm not so sure of that Pete - I think that was a theory and it didn't work out. I think the keyway being broached too far up the shaft was what was found.. The old ones you could see the keyway when the prop was mounted,the new ones prop covered the keyway completely on the pictures I saw on PN. Couple of cable ties and some black tape would fix it right up ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: KENO
Date Posted: December-11-2020 at 3:55pm
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Maybe your friends shaft is still together because they solved their problem in the last year or two and a lapping job did nothing to prevent breakage. That many broken shafts on one boat must be a record, I think CC would have wanted that boat back to do a little root cause analysis. Just think of all the money and resources expended over the years by a bunch of engineers at CC, Acme and various shaft suppliers and who knows who else................and all they had to do was listen to Pete and do a little lapping. They should all be fired
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Posted By: 8122pbrainard
Date Posted: December-12-2020 at 5:06am
Yes, I understand the keyway position was determined to be a problem. My friends last shaft broke after the change was made. It was clear that the forward area of the prop/shaft taper wasn't seated. The material removed for keyways causes a weak spot and also stress in the area. It would be interesting to know if they ever considered not machining the keyway in the shaft at all?
------------- /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 < |