Prop. Casting Pics

[maa. melee]

I just got the propeller back this morning out of the oven where it has been sitting for a few days now. According to the guy there, it's completely stress relieved and ready for machining. (Plus it's a nice frosty color smile.gif )Mind you this prop. is still VERY ROUGH. In fact, you can still see the 'green' (black in color) sand from the flask on the prop. and the sprue on the hub. The hub is oversized in length and will be ground to perfection. Next step, basic grinding, then balancing, then final grinding, then balancing....
prop1 (http://img.photobucket.com/albums/v197/maa_melee/prop3.jpg)
prop2 (http://img.photobucket.com/albums/v197/maa_melee/prop4.jpg)
prop3 (http://img.photobucket.com/albums/v197/maa_melee/prop1.jpg)

[nedL]

OK, I'm impressed, very nice! Looks a bit like a cross between a traditional "Tru-pitch" and an "Equipoise" design. What is the diameter?

[Bruce Hooke]

Wow! How are you planning to do the machining? I knew a guy who wrote software to guide a CNC machine to shape BIG props. There must be a simpler way to do the job, especially on a small prop like yours, but it sure is a complicated shape and I'd imagine tiny differences in shape probably make a big difference in performance...

[maa. melee]

Actually Bruce I'm on a break from machining the hub. Since the sprue was 'lower' than the blades I couldnt use my bandsaw to cut it off because the blades might get damaged. I locked the whole prop. hub in a 3-jaw chuck, each jaw between 2 blades, and endmilled the sprue off, and used a dial indicator to make sure I was cutting parallel to plane containing the aft most points of the trailing edges ( :confused: uuuummmm????) After that I used a hand air grinder (like a dremel) with a steel burr to grind off most of the excess material that spilled over. Still alot of work to do!

THIS MIGHT HELP (http://img.photobucket.com/albums/v197/maa_melee/prop4mill.jpg)

Editted to indicate diameter. Diam=10"

[ 11-19-2004, 02:28 PM: Message edited by: maa. melee ]

[Garrett Lowell]

Very cool. And what will be wearing this handcrafted prop?

[maa. melee]

Work Skiff 18' (http://www.instantboats.com/skiff18.htm) When I finish building it hopefully next spring.

[Bruce Hooke]

Actually, what I was talking about was machining the surfaces of the blades, but maybe you aren't even worried that much about that.

[maa. melee]

The surfaces are amazing clean, smooth, and within tolerences. I made some guages and jigs for different blade cross sections and this will help me as I manually grind away.

[brian.cunningham]

Nice work!

Did you use software to design the prop, if so which?

[alteran]

Have any pictures of the engine you were telling us about?

[maa. melee]

I didnt use software to design the prop. Actually I just kept it around 10inch DIA. and having a decent pitch. The later done by eye. I kept the hub DIA. aroun 1.5" and made sure I had resonably thick fins to facilitate pouring because I could always grind them down. Im working on figuing out exactly what engine I need.

And no pics of "clanky" engine yet, alteran. Ill keep you posted.

[Victor]

Yeah, cmon, I'm dyin to see this motor!

[Paul Pless]

Victor,

While you and I rarely agree in the bilge, I sure do wanna see some pics of that motor.

Paul