prop treating

[Gary]

Anyone have a good source that will do Nitride treating for stainless props? Cryogenic treating will not work so can't do that.
Thanks

[fweasel]

Nitride hardening is a common treatment of performance automotive engine crankshafts. Perhaps look up a local engine builder or machine shop and see if they can help you out.

[rol243]

Gary, theres really not much point in hardening up a stainless steel prop to be used for electric power . this is more common when using berillium props which are used for high performance gas powered boats. stainless props are pretty tough.

[Gary]

Well the berillium would last 25% less than the stainless that I use. Right now I can usually get 10 runs before I throw a blade with stainless. I don't mind buying lots of props..... it's just getting them each to be exact every time and that's the part that really sucks.

[fweasel]

Out of curiosity, how fast are you spinning these props that you're throwing blades so often? And what diameter?

[Gary]

45-46,000 rpm, 48mm in a Phil Thomas 45

[dasboata]

45-46,000 rpm, 48mm in a Phil Thomas 45

who's SS wheels are you using CNC ed?

[CraigP]

Sounds like SAW rotations.... I think you need the whole prop shaft and prop to be balanced at those speeds as an assembly. Not many have that kind of rig...

[Gary]

I use Prather props right now and yes it is for SAW.

[CraigP]

Have you heard of anybody using a rotational assembly balancer for RC Boats? I’m just not sure you can do it with a flex shaft, it requires too much diametric clearance in the application. If I was running those speeds, I would definitely use a solid shaft on roller bearings and balance as an assembly. The amount of blades you lose means your running in water with much floating debris or your prop is suffering from occipital lobing, which is a secondary harmonic vibration and it’s really destructive! I learned the hard way about this balance issue when I started pushing an 871 blower on a blown alcohol digger up towards 40,000rpms. BTW, love the Prather SS props!

[Shooter]

Gary,

Glad to see you are back at it! I still can't believe how fast you have that boat going! I'm not sure if it's what you are looking for, but there is a process conducted on SS by Bodycote called Kolsterising. They ran samples for our hydraulic components years ago and it was relatively inexpensive. Might be worth a call.

http://www.bodycote.com/en/site-serv...sterising.aspx

[dasboata]

prop treating

Sounds like SAW rotations.... I think you need the whole prop shaft and prop to be balanced at those speeds as an assembly. Not many have that kind of rig...

How would you be able to do that Craig I would say impossible on a flex shaft


Sent from my iPhone using Tapatalk

[CraigP]

They have those balances for airplane propellers that you can use with a shaft. It my understanding that they are more accurate than magnetic types, although I don’t use one, but I’m not trying to spin 45K either! This would probably work with a flex shaft, but the clearances needed to run the flex just makes balancing it a joke, IMO.

You guys got me thinking, a fairly dangerous thing! I think I would use the 3/16 hardened stub shaft, put a piece of flex on that just to make the bend. Then put a piece of straight shaft to the other end of the short flex. You’ll need a lathe to tool the hole into the straight shaft, so you can make a good brazed welded attachment. This would allow a bearing clearance for the majority of the drive line and only having it loose for the short piece of flex. What you guys think about that?

[Gary]

Thanks shooter....just gave Bodycote a call and they are going to get back to me!

[Gary]

Well now they want to know what type of stainless it is and I can't find any info on it. I will keep searching tonight.