Reboring and Rekeying a Prop

[fstbttms]

Originally Posted by mikogold

Isn't there a standard procedure?

Sure. But what it is depends on if you listen to people who do this work for a living or if you listen to someone who heard it from a guy in the yard who heard from the old salt down the dock who said that's what commercial fishermen used to do back in the day.

[model 10]

Originally Posted by NoTies

The overwhelming body of evidence and best professional practice is against you on this.

Pete; That is just not true. As if it matters but I am a a very experienced aircraft mechanic. We have been using anti-seize compound on tapered prop shfts ever since they figured out that if they used white lead on a tapered shaft they could get it off again. Granted powered boats have been around longer but do you really think the quality of a boat is equal to an aircraft? Not from what I can see.

[fstbttms]

Originally Posted by Guy

Pete; That is just not true. As if it matters but I am a a very experienced aircraft mechanic. We have been using anti-seize compound on tapered prop shfts ever since they figured out that if they used white lead on a tapered shaft they could get it off again. Granted powered boats have been around longer but do you really think the quality of a boat is equal to an aircraft? Not from what I can see.

Do yourself a favor- call your local propeller repair facility and ask them what they think. Please be sure to report back here when you've been re-educated.

[model 10]

Do you really think I need to be "re educated" because you don't agree with me. Sorry pal but I hold you in pretty low esteem when it come to this. Why on earth would you think that 100 years of good practice is wrong because you think so? So if you need proof call a prop shop yourself and ask them what they put on a tapered shaft, I don't need to.

[charliehows]

Originally Posted by bobconnie

Gee fella take from a 50 yr machinst, the keys is 90% of the job !! It's what holds all the power to the prop!! No way can ya do a really decent job with a hand file !! To pay a pro to bore it and then take the chance of messing it up trying to save few dollars seems like a penny wise and dollar foolish decision. Just my 2 cents

have to disagree - its the result that matters, not the method, i've designed, engineered, finagled and bastardised all sorts of machinery over the years and, although i agree its better to get a job like this done properly, you bloody well could do it with a hand file if you had to. But 'had to' means you're sitting on a beach in the Marquesas or something, not saving a few bucks...

[NoTies]

Originally Posted by Guy

Pete; That is just not true. As if it matters but I am a a very experienced aircraft mechanic. We have been using anti-seize compound on tapered prop shfts ever since they figured out that if they used white lead on a tapered shaft they could get it off again. Granted powered boats have been around longer but do you really think the quality of a boat is equal to an aircraft? Not from what I can see.

I don't know much about aircraft so won't comment much but as this is primarily a boating forum and marine engineering is my profession I do feel eminently qualified to comment. They operate in different mediums so a different set of problems. Now I realise you are talking about aircraft I can understand the use of a very carefully controlled amount of antiseize between the taper surfaces as I guess an aircraft prop is engineered a lot lighter than a boat prop so wouldn't hold up to well to the stresses of removal. I worked in supply & logistics for the NYANG for a while and saw how the line shop guys operate, they are positively anal, which is a good thing. I wouldn't, however, trust the average boat owner or even a marine professional to fit a prop wet. I can just imagine handfuls of grease oozing everywhere.
A little more clarity would have been nice before I went all medieval on your ass.
Do you spray the white lead on to obtain even, proper film thickness?

[NoTies]

Originally Posted by bobconnie

You show me a prop installed without a key that will not slip under power sooner or later and I will gladly change my opinion!

Examination Notes For Marine Officers: Securing propellers
I predict you won't change your opinion though. An opinion is not a fact, no matter how strongly it's stated.
There is another type of machinist in this world. She generally can be found in a sweat shop in Bangladesh and no matter how many pairs of pants she sews up she will never be a clothes designer.

[fstbttms]

Originally Posted by Guy

So if you need proof call a prop shop yourself and ask them what they put on a tapered shaft, I don't need to.

I have called a prop shop (the largest one on the West Coast, BTW) and asked them this very question. But as an aircraft mechanic, you clearly know everything there is to know about boat propellers and can't be told anything about them.

But hey, I get it. You're backed into a corner and can't admit you're wrong. Not the first time I've seen it here.

[captain58sailin]

Every prop I have pulled in the last 45 years was put on dry. I have always installed my props dry. From my perspective it is harder to keep the prop on the shaft than remove it, the point for me is to insure the prop doesn't come off until you want it to. To address the OP you can have the hub of the prop machined out to match your prop size. I use a local machine shop for these kinds of modifications, but our local machine shop works primarily in the marine applications. I would insure that the taper itself is smooth and clean before lapping the prop to fit the taper. I usually perform my prop and shaft work at the same time so that they are balanced and matched as well as possible before putting them into use. That means having the shaft trued and the spots where the cutlass bearings have been riding built up and turned down to diameter depending on the amount of wear.

[Cheechako]

Originally Posted by fstbttms

In the case of a sailboat prop shaft, what is being located? The prop's orientation on the shaft is irrelevant.

Yeah I dont get it.... if the taper drives the prop 100%, why is a key needed at all?

[NoTies]

Originally Posted by Cheechako

Yeah I dont get it.... if the taper drives the prop 100%, why is a key needed at all?

See post #40

[mikogold]

ok guys, i went to fred$jamie and got the prop bored. it turned out that even if my shaft is 30mm the tapper is a regular 1 1/4 tapper. sice I was there i asked about a few questions:
- what moves the prop, is the tapper 100%. the key is just a safety feature in case the prop gets loose. a properly tappered prop doesnot need a key to work.
- the props are always installed with a dry feet, nothing in between the metals.
if you lapped the prop you put something in between to do that but then you remove it and is a dry fit.
cheers