Shaft Metal

[Sakura Maru]

Hello, when making your own prop shafts, meaning the rod that actually holds the prop, what sort of rod metal are you using and how are you threading it?
Revell

[patmat2350]

Some use brass or even aluminum... seems to work ok within limits, but for best durability you want stainless steel (NOT plain steel!).
And it's best to get stock that is precision ground... sometimes hobby shops have SS rod which is rough, oversize, and/or not straight.
Stainless is tough to thread, even when gripped in a lathe chuck, but it can be done.

If that's not for you, contact one of our better suppliers for a custom built shaft and stuffing tube.

Pat M

[Sakura Maru]

Thanks Pat,
I've been having a go at threading 303 stainless (bought from Small Parts Inc.). It IS tough, it just spins with the die when clamped in a vise. I may just have to send these pieces out and have them done at a local machine shop. While your suggestion makes perfect sense, I like to try making my own stuff so I don't have to wait for it or send out to Europe.

[frankg]

:) SAKURA MARU- I thought I would give you a heads up for stainless steel precision ground shafting and three bearing stuffing boxes with “O” ring seals. www.mackproductsrc.com :)

[Sakura Maru]

Link don't work....

[Aerominded]

Try

www.mackproductsrc.com

;)

[Umi_Ryuzuki]

I just use 1/8" or 5/32" brass rod.

I drill out any threads in the prop and silver solder the propellers on the shaft.
Had the same propellers on one boat for 20 years.

:)

[patmat2350]

A trick that helps for me:
Use a vise with sharp teeth or serrations on the jaws, and grab the shaft BETWEEN the bearing surfaces.
After threading, hit the damaged area with a file so that it will pass through the bearing's bore.

[Sakura Maru]

I just use 1/8" or 5/32" brass rod.

I drill out any threads in the prop and silver solder the propellers on the shaft.
Had the same propellers on one boat for 20 years.

:)

You don't get that galling / seizing problem I've been hearing about? Or is it because the rpms we're dealing with in tugs and other scale ships aren't enough to heat up the sleeve/shaft joint?

[patmat2350]

As long as you keep lube on it, it will work. Our scale applications we just don't have the loading that requires the traditional hard steel journal on a softer bearing alloy.

One area where it makes a difference- whipping. Long unsupported shafts (like the span between two bearings in a long stuffing tube) can start to whip once the shaft reaches its critical speed. Steel will perform something like 3x better (higher speed capability) in this regard.

My personal preference: Go with the better stuff if I can, just because I can: Precision ground stainless and removable/servicable props (sorry Umi!).

[pompebled]

For scale ships, I use whatever is at hand, for my fast electrics I only use spring steel, which works better than the softer stainless shafts.

It is a bear to thread, I use the lathe in a metal workshop of a friend (and sometimes even his staff, to do it for me...) and it needs to be sanded down to fit the ballbearings, but I never have had any problems with running these springsteel shafts, just keep them greasy, as they most certainly will rust.

Regards, Jan.

[Umi_Ryuzuki]

You don't get that galling / seizing problem I've been hearing about? Or is it because the rpms we're dealing with in tugs and other scale ships aren't enough to heat up the sleeve/shaft joint?

I think I replaced the shafts on that "20 year old" boat recently...
Or maybe I just thought about it... can't recall. There is wear at
the bearings, but I have never had a stuffing tube and shaft seize up.

I would imagine that is because of the lower RPM.

_______________
_______________

Pat,
No problem,.... I don't know everything... I just think I do... :p

What echo's in my mind here is Cliff Shaw's old saying,...
You CAN'T DO That.....

Which essentially means
"sure it works for you", or
"It works for now... " or the long version,
"You don't know what,... parts, metals, machining, voodoo magic,... went into
the construction by "X" person, so "you" can't do it the same way".

:)

My problem has always been that the stainless steel tolerances were
different than the brass tolerances, and the shaft/bearing sizing never matched.