prop bending 101

[Duke]

Part 1

This is how I do it. Surely there are better ways and room for improvement but I wanted to share what I have.

I use an old Reese reciever with a 3/4 hole, scrap 1/2" aluminum plate, Solas prop tool, 3/4" -6 1/2" bolt with nut and a 24" cresent wrench. The bolt must be 3/4" to keep everything from having any movement. I also like the 24" cresent because it gets all the way to the root.

[Duke]

Part 2

Part 2

Using the plate allows you to set the prop gauge down as you are bending. This saves a great amount of time back and forth doing each blade. The Solas removal tool keeps the prop from moving while you apply pressure downward. If it still moves you can hold it with a wrench on top.

I was able to bend a stock DF 14-20 ( really 13-19) to 24 degrees like it was butter. The entire process only took about 10 minutes for all three blades!

Also try to keep the transitional curve as smooth as possible. Mark each blade the same amount up or down that you want for your desired pitch. Some only picth the trailing edge 1" while others go as far as 2 1/2". Only use the bottom of the impeller as you guide with the gauge, this is the thrust side of the blade and it tapers from top to bottom over a degree as it reaches the tip.

[800AMSOIL4U]

Great information. Thanks.

[steach]

I made a plate from scraps for my winch that looks like that. It's 2" box stock with a 1/4" plate welded to it.

I was going to make another one for a 5" vise but now I'll leave room for a prop, Thanx

[RX951]

[rossnemo]

(Some only picth the trailing edge 1" while others go as far as 2 1/2".)

Cool post Duke...Is the end result any different if the bend stops at 1 inch or goes to 2.5 inches up? This looks like what kawasaki calls a variable pitch impeller. My stxr stock impeller is listed as a variable and tails down the last inch just like the one you are showing after you bent it.

[jpa1300]

Duke:
Where did you get the prop gauge?
Thanks,
j.p.

[Mr Bill]

get your prop gauge from 2fast4u....

[Duke]

(Some only picth the trailing edge 1" while others go as far as 2 1/2".)

Cool post Duke...Is the end result any different if the bend stops at 1 inch or goes to 2.5 inches up? This looks like what kawasaki calls a variable pitch impeller. My stxr stock impeller is listed as a variable and tails down the last inch just like the one you are showing after you bent it.

Thanks Ross, the main reason for varying the length of the pitch is the amount you are changing. For example, going from a 19 to a 24 in only an inch would be too quick of pitch change causing a bind in the water flow. The smoother the water flow the better.

Variable pitch refers to the leading edge being different then the trailing. I believe most are variable pitch these days.

[Duke]

Duke:
Where did you get the prop gauge?
Thanks,
j.p.

The gauges I have are from Watcon but only because I didn't know Tommy (2fast4u) sold them. His look great and I believe are a little better priced.

[Duke]

Part 3

Also take note that when bending a DF for the GPR the outside diameter grows as you increase pitch.

You can carefully file or grind the outside of the prop while setting it squarely down on the liner marking the stop point each time. Jim's Performance can cut the OD for you also. Small tweeks back and forth don't usually require much fitment after the initial cut.

I believe .015 total clearence with prop loose in liner is ideal. .007 to .008 all the way around if bolted together. If running Carl's PVC insert it can be much tighter. Someone please correct if this is wrong.

[jeffsntx]

Also take note that when bending a DF for the GPR the outside diameter grows as you increase pitch.

You can carefully file or grind the outside of the prop while setting it squarely down on the liner marking the stop point each time. Jim's Performance can cut the OD for you also. Small tweeks back and forth don't usually require much fitment after the initial cut.

I believe .015 total clearence with prop loose in liner is ideal. .007 to .008 all the way around if bolted together. If running Carl's PVC insert it can be much tighter. Someone please correct if this is wrong.

Duke, I am having a problem with my ski turning WAY too many RPM's with the 14/20 Dynafly and the plastic liner I bought from Carl. I am going to pull the complete assembly apart tonight and see whats going on. I was under the assumption that the plastic wear ring would have to be "burned in" to the new prop. When I assembled the pump it just slid right in, so I am going to check clearances tonight and i will let yall know.

[WFO]

Good stuff Duke. I like that flat plate idea.

Very true about the outer diameter on the Dynafly. IMO do not try to cut it yourself, or even bend it unless you know and are confident in what you are doing. Jim does cut them, but so does Carl @ Island Racing, Erick @ Speedfreeks, Dave @ Impros, and any other actuall prop shops.

[Duke]

Good stuff Duke. I like that flat plate idea.

Very true about the outer diameter on the Dynafly. IMO do not try to cut it yourself, or even bend it unless you know and are confident in what you are doing. Jim does cut them, but so does Carl @ Island Racing, Erick @ Speedfreeks, Dave @ Impros, and any other actuall prop shops.

Those are great shops too! I often but unintentionaly overlook them because Jim is so close to my location.

Just trying to help out the diehard do it yourselfers like me.

[jpa1300]

Duke:
I found the Watcon unit; how do you contact Tommy for his version?
j.p.