New Prop install question ...
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Engine Repair
Forum Discription: Engine problems and solutions
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=31174
Printed Date: October-08-2024 at 7:26pm
Topic: New Prop install question ...
Posted By: damonwells
Subject: New Prop install question ...
Date Posted: August-12-2013 at 5:14pm
| I just installed a new prop and hopefully properly used lapping / grinding compound. What is a good trick to hold the shaft in place without spinning while rotating the prop back & forth with forward pressure until there isn't much grit left to the compound ? Thanks, cheers, John |
Replies:
Posted By: ArtCozier
Date Posted: August-12-2013 at 6:42pm
|
Maybe I'm a careless boat mechanic, but I betcha over the 49 years that I have messed with inboard boats, I've probably installed a thousand props, and, except for an unlimited hydro (9000 RPM) I've never lapped a prop to the shaft. I have occasionally used Dykem Blue to see whether there is a high spot if there was a vibration problem. Art ------------- "Art" |
Posted By: boardersdad
Date Posted: August-12-2013 at 7:05pm
|
Many common questions are addressed in the: http://www.correctcraftfan.com/forum/forum_posts.asp?TID=27356&title=ccf-faq" rel="nofollow - CCF FAQ . This thread covers http://www.correctcraftfan.com/forum/forum_posts.asp?TID=12866&KW=lapping&title=proper-prop-installation" rel="nofollow - prop lapping . |
Posted By: boardersdad
Date Posted: August-12-2013 at 7:07pm
|
btw, I lapped my prop onto the shaft and I'm happy I did. Really improved the contact on the taper, which is what transfers all the propeller force to the shaft. Steve |
Posted By: damonwells
Date Posted: August-12-2013 at 8:00pm
| Thanks Steve ... I have and used that article, excellent. Perhaps I missed it, but I didn't see anywhere in there a good suggestion on how to keep the prop shaft spinning while lapping ? Cheers, John |
Posted By: baitkiller
Date Posted: August-12-2013 at 8:06pm
|
Take a short line and tie a figure it around the shaft coupling and across 1 or both mounts. Its not allot of torque. i have a shaft zinc on my boat so that gave me some purchase with a pipe wrench. ------------- Jesus was a bare-footer............. |
Posted By: boardersdad
Date Posted: August-13-2013 at 5:46am
|
Sorry, John, I forgot about the article below, which I had reviewed. He says, "It helps if you have locked the gear box into gear." As baitkiller said, there's not a lot of torque involved in lapping the prop. When you tighten the prop nut, you want to use a block of wood or a strap wrench. http://www.pbase.com/mainecruising/fitting_a_prop" rel="nofollow - Lap Fitting A Propeller To A Shaft btw, you said, "until there isn't much grit left to the compound". I don't think you need to do that. I needed 9 or 10 lapping revolutions to improve from about 66% contact to 85% to 90% contact (checked with Prussian blue). See http://correctcraftfan.com/forum/forum_posts.asp?TID=11467" rel="nofollow - this thread . The lapping compound I wiped away at the end still felt gritty. As it says in the article, you don't want to overdo it. Steve |
Posted By: 8122pbrainard
Date Posted: August-13-2013 at 7:33am
This only works with a manual trans. Most here have hydraulics which need the engine running to develop pressure to lock up ether of the clutch packs. ------------- /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 < |
boardersdad wrote:Posted By: damonwells
Date Posted: August-13-2013 at 3:18pm
|
YUP, in gear and engine not running, shaft spins ! Perhaps I need to invest in a strap wrench, Rigid Tools looks like they make a nice one. Thanks again, cheers, John |
Posted By: ArtCozier
Date Posted: August-13-2013 at 3:37pm
|
Couldn't you just put a pair of vise-grip pliers on the head of each coupler setscrew and let the handles bear against the bottom of the boat? Or put a large C-clamp on the coupler in such a way that it locks up the shaft. Just remember to remove it before you go to run the boat! It's a boat, not the space shuttle! Art ------------- "Art" |
Posted By: phatsat67
Date Posted: August-13-2013 at 3:59pm
|
Get a buddy and one of those rubber style wrenches around the shaft or coupler? Pete is a lapper guy.(Not that there's anything wrong with that! Seinfeld fans haha). I am a if it is smooth when I install it then its fine kinda guy. If shaft run out checks out and a vibration is still present with a new prop lapping would be something I would do. ------------- |
Posted By: boardersdad
Date Posted: August-13-2013 at 7:01pm
That's right, Pete, I forgot about that. |
Posted By: 8122pbrainard
Date Posted: August-13-2013 at 7:10pm
I have clamped a couple pieces of wood on the shaft. Remember if a ARE shaft is installed, it does not use the big sq. head set screws. No, we aren't building the space shuttle but, a proper taper fit is a basic mechanical engineering principle. ------------- /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: damonwells
Date Posted: August-15-2013 at 3:25am
| THANKS everyone for the excellent suggestions ... cheers, John |