Adding or subtracting rake??

[Mark75H]

Ron, can you add or subtract rake the same way you change pitch or is rake pretty well set when the blank is cast?

[zuperboat]

I was told you can change the rake but its expensive. I believe they heat the prop change the rake or pitch, only slite changes. Then reharden the prop with a cryo. I have heard of it being done but thats not something I would accept. EVER!!!!

[Mark75H]

I have worked in a prop shop and changed pitch on props. Sometimes heat is needed, but not always. Some props may be hardened, some cryo'ed, but most are not. If they were all hardened, few would ever bend, instead they would just loose a blade and Ron's advice to repitch in a vise with an adjustable wrench would be impossible. :)

Back the my question ....can Ron change rake on props?

[Ron Hill]

I'm assuming, you want some dialogue regarding my thoughts about RAKE...

Ground Rules...As Butch Cassidy said...

Pitch...12 inches of pitch, the angle the blade is on, to go 12 inches in one rotation of the prop!

The pitch gauge is on the 20, just to help you get the idea...

[Ron Hill]

The angle of which the blade is on the hub....Now, my way of measuring isn't fool pfroof, but this is HOW I DO IT..

My rake guage is lined up the go right through the middle of the propshaft. and I call the rake, the place where my straight edge is flat...frequently, on a cleaver this is the trailing edge...

So, we agree to pitch and rake...

ADD; Rake is the angle of which the damn blade screws down into the water....A ZERO RAKE works great on submarines.....because the prop is 100 per cent under water....Each pin hole in an OLD OUTBOARD was 5 degrees...15 degress rake,same as three pins out, with the propshaft parallel with the bottom...The higher the rake, the more bow lift....because the prop screws down into the water, pulling the transom down, lifting the bow....

[Ron Hill]

Nothing is easy, but, this, again, is how I do it...(AND honestly, I don't worry about rake...because I use my eye...I worry about pitch...)

Here is a 15 degree cleaver, but I measure it as a 12...

[Ron Hill]

Here is the REPITCH IT YOURSELF PROP...

Picture one.....is the "STOCK BLADE" and measures 5 degree..

Second blade/Second Picture: Increased pitch, resulted in lose of 5 degree rake...

[Ron Hill]

Do I change them in WAX???

Blade one: Straight rake on the traling edge...

Blade two: Laid back blade...


So, do I change the RAKE in WAX...SURE do!

FYI: I'm sighting down the blade that is pointing at me (you)...

[Ron Hill]

Ok, here, I'm adding diameter to a 45 wheel....my goal by adding diameter will be to lower the rake, a degree or two, as I feel the bigger diameter will carry the bow....rake, doesn't help speed, in my opinion, it helps handling...

[Ron Hill]

Here is BONDO off a good 45 wheel...

Notice how the tip lays back...She lays back about an 1/8 in one inch, with 7 degrees rake.

[Ron Hill]

Interesting, I was working on RAKE most of the afternoon yesterday...all on 45 wheels for Chad....

Same wheel, no heat, just a hammer and block of aluminum.....Straight bad edge, 3 degrees more rake...

Which pro will lift the bow the most???

[Ron Hill]

We ran great at Bakersfield...we didn't wreck out boat. We didn't tip over. We didn't break our motors...our drive got practice, and we didn't beat anyone...

But, I added a little rake to the wheel..I felt we weren't carrying the boat on the prop, so I added rake...About 3 degree on the tip...or 1/2 pin hole...Our driver is 210.....in a 45...he can use the lift!

[Ron Hill]

I rolled the tip just a little to get the bow up...

You can't really see what I did on the last two pictures, but I just rolled the tip a 1/16.... just "bent it" over a socket wrench...with a small hammer...seemed better, we got third the last heat...Of course, I borrowed a wheel from RJ West...

Hey, what can I say..

I know a lot about props...If it is a good one keep it...don't give it back...don't get it copied...keep it...

I like straight trailing edge, some guys really don't, they don't like to lift the boat, they like to push the boat...

[Ron Hill]

Sam,

Since you asked this question, I could not remember his name...

When Capnzee (Rod Zapf) ran 280, I helped him with props...Then when he went "BIG TIME" and got a 5 Liter, he ran big mother Mercury Props...He bought the boat from John Gibbs and Gibbs had made props for it, but for some reason Rod sent his 5 Liter prop to George Lockhart. It was a 15 degree Mecrury cleaver...Rod had wanted more bow lift...

After he got it back from George, that thing had about 22 degree rake, and he had bent it at the hub. Totally beautiful work...Must have gotten it pretty hot, because where he bent it, she was ove a half inch thick...The prop ran well...wasn't the first time I was impressed with his work or the last.!

Ron