sharpening props, what do you use

[phillnjack]

Some people dont like sharp props, but some people like myself like to have real sharp propellers.


Here is my super time saving blade sharpener.
This little gadget will get a propeller razor sharp if you want to go that far.

a few might laugh at this little gizmo and think its rubbish and wont work.....
Believe me, after 5 minutes on a stainless prop with this and the blades are very sharp .

what do you use to sharpen yours ?

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[282]

I have never touched a prop, just sent it to a prop shop if needed. Interested to hear input on this.

[phillnjack]

anyone ?
come on , some of you must have cut yourself on the prop blades.

[frogII]

metal file , just to clean up the nicks & burrs
never had one sharp enough to hurt myself

[whipper]

hand File and have tried a diamond stone before also but nice quality fine hand file seems to work best. Not big fan of super shave sharp. Every prop Ive tried that was like a razor has cracked!!

[XstreamVking]

I have been told not to use a steel file on a stainless prop by my prop repair guy.

[whipper]

I have been told to not use a steel file on a stainless prop by my prop repair guy.

Yes never use a regular steel off the shelf file. There are hardened files made for stainless. I dont know what mines called of the top of my head but i know its for SS / Cobalt ect.. Just ask an old Machinist they will show you the right tool for the job. i think working with any thing Stainless the tool needs to be hardened material. Ceramics,Diamond, hardened to Vickers 1200+..They make real nice hand files but needs to be quality, not any old file.

[phillnjack]

I always preferred the stones and oil to get things real sharp, until this little gadget turned up.
Not had a problem with getting too many nicks in props, well not in stainless, I have crunched up few alloy props hitting big chunks of wood though.

now ive said I have not damaged a stainless you can bet next time out I will bugger one right up.

[eli]

probably cool tool i m old school strips of sand paper and small smooth hone stone

[Euroski]

Have any before and after performance results?

[phillnjack]

for comparison on a prop I sharpened back in the spring I got huge gains by sharpening it.
remember I only have a 60hp triple evinrude on a 13ft tri-hull type boat so these are not going to be huge gains as with 200hp plus motors.
I tried a Omc 12 3/3 x 23 alloy prop (omc 390895) , it was brand new and to be honest a total piece of crap for my boat.
it was terrible for prop walk and once it got to 35 - 36mph it was trying to corkscrew the boat to the point of danger. and veering left at the front.
Holeshot was very poor and just a nasty handling prop full stop. top speed was 38 mph and could only get engine to 5500/5600 rpm.

So I set about sharpening it up as the leading edges on the prop were very blunt and very thick.
I tried it and the holeshot was drastically improved and handling much better, no more prop walk and top speed 41.3mph at 5900 rpm.
also very noticeable at just above idle speed there was no large bump of water at the right hand side of engine like before.
so to me that's a huge improvement, before it was sharpened it was not a usable prop, just emergency get you home job.

Last year I was using a 13x19 sst ( omc 384142 )and gained 1.5 mph by sharpening the prop, it was in good condition already, but not sharp.
Holeshot was the pretty much same, as far as I could notice but mid to top end picked up slightly better, and top end rpm up by 200.
1.5mph is a huge gain when chasing every extra bit trying to get to 50mph.

I have experimented a fair bit over the years and always found a slight improvement by having props very sharp.
On alloy props you can sharpen but they must be a right on the last bit and not a tapering sharpness or they will just nick up in salt water.
stainless props I have had are NOT thinned props, just very sharp. I dont have a problem with them breaking because I dont have a large
edge of the blade sharp, nothing like what Winrace do to theirs, they have about 1/2 inch area ground all along the leading edge.

on my Campion Allante 195 with a Volvo 290sp outdrive I had a 23p stainless and sharpened that, and to be honest I could not see or
feel any difference.

my problem with ultra sharp props, is me always forgetting I have sharpened the ba****ds and cut myself to bits handling them.
on the boat its no problem as I use the red plastic PROP SOX to keep the props from getting nocked about or hurting anyone near the boat.

[dpanky]

The theory is to remove just as little metal as possible from the prop using the finest grit possible. Remove metal only from the back of the blade around the leading edges, never from the front. Keep the sanding paddle wheel or disc moving so as not to create flat spots on the prop, and blend in the metal over large areas.
I hold the prop firm using blocks of wood or a bench vise. Use heavy cloth to protect the prop in the vise, and make sure it is tight. Direct the drill in the proper direction so the rotation does not grab a sharp edge. Wear eye glasses and a mask.

The paddle wheels and polishing wheel can be purchased at Menards, Fleet Farm or ACE hardware.

I usually sharpen the back of the blades first, using the 3M medium and fine paddle wheels. They can take off a lot of metal fast, leaving only small scratches. From the back of the blade, use the paddle wheel to shape a straight sharp edge of the props leading edge from the tip to the hub. Keep moving the wheel and blend in over a large area. Touch up the leading edge of the prop blade with folded sandpaper, running the paper up and down the blade until sharp and smooth.

The front of the blade usually has scratches, and these can be removed either with the paddle wheels above, or with the screw-on 3M fine grit papers onto the 3” backing, 100 or 80 grit.

Once the major work has been done above, it is hand sanding with wet or dry sandpaper. I use 9” x 11” sheets, cut into fourths, then folded two times to get a sanding surface of 2 ¼” x 2 ¾”. Dip the sandpaper into water and apply pressure to the prop. Depending on the depth of the scratch, one may go from 220, 320, 400, 600, 800, 1000 to 1500 grit. At about the 800 or 1000 grit, use the buffing wheel on the end of a drill. Apply liberal amounts of Mothers Mag & Aluminum Polish to the prop held in the vise and apply pressure to the area to be polished. Polish with the buffer in the correct direction. The surface should turn mirror like. Apply Mothers again if necessary, or sand areas again that cannot be polished out. Polish one blade at a time, rotate from blade to blade on the one side, turn the prop around and polish the other side. Finish the hub and other areas.

Finish up by hand polishing the entire prop with the Mothers, inspect prop for any areas that need to be redone.

[phillnjack]

thats a nice pair of polished props.
they look proper bling and like brand new.

an old prop shaft would be absolute perfect with a flat on the part in the vice.
I would not use aluminium polish on a stainless prop, takes too long, use correct grade for the metal and then go through the grades to get the results you want.

we all have our own methods of polishing, so its what suits us best.

once again those props do look very very nice.. is that a Raker and a SRX ?

[dpanky]

Yes, a 22" Raker and a 23" SRX. I hold the prop in position on the bench with blocks or in a bench vise, making sure a thick cloth between the prop and the vise prevents any scratches to the prop.

[olboatman]

Very nice job dpanky! When I was younger I would sharpen the back leading edge of my brass(bronze if you must) props with a fine file then sand smooth. I sharpend the aluminum prop used on my modded 25 hp OMC because I couldn'd find any ss of the proper fit or size. I did see a rpm increase (just over 100) but didn't have gps to check speed. Used a Dremel with a carbide burr then sanding wheel and finished by polishing the whole prop. I was reluctant to touch my ss props but dpanky may have opened that door.....WTF as my framer says" its nothin money can't fix"! Gary