Tungsten flywheels anyone?

[rschaffter]

no matter what anyone says,
I find the uranium story hard to believe.
uranium is a lot of fuss to machine.

It is quite possible it is true. 

Skpigear's post about half way down the page has some correspondence with Jim FitzGerald and a photo of the Cotton Brute; a 24 oz N-scale locomotive is pretty impressive...

http://forum.atlasrr.com/forum/topic.asp?ARCHIVE=true&TOPIC_ID=49615&whichpage=3

[SandyEggoJake]

Max,

In general, I'm v interested in some for a scratch built odd 0-6-0 switcher I'm doing.   As much as I would love the cheaper solution of a brass 14mm, my boiler will be a mere 74" scale OD (11.75 mm) x 225" scale length, so larger brass flywheel is not be an option. 

But neither of the stock motors I'm contemplating for this build have 7mm long flywheels.  Victor had suggested trying the Micro Ace 5 pole off the Atlas 2-6-0 mogul (http://www.spookshow.net/loco/atlas260.html) which I'm 90% sure I'll need to abandon given its 13mm diagonal dia of its square motor magnet might not take to kindly to so much shaving) or Bachmann's tiny sub 9mm OD coreless 5 pole off the Spectrum 4-6-0 ( http://www.spookshow.net/loco/spec460.html) which comes stock with a mere 1mm wide brass flywheel fixed to the shaft between the motor and worm. 

Still, I'm wondering if you might find broader interest to have 10 mm W flywheels cut in smaller lengths, say 1 or 0.75 mm (standard washer lengths)?  Then those needing more weight or more room can stack them and/or experiment with them adding more or less weight.  Cost per item would be far less as well and using smaller / standard stock might for automated machining, further reducing the price per unit.

Ironically, there's a group here my neighborhood the specialized in W parts.  http://www.tungstenheavypowder.com  They already make "tungsten penetrators" (armor piercing rounds) as well as moly furnace washers all to military spec.  On a whim I gave them a call to price out a 10mm x 1mm x 1.5mm bore W washer, and they are confirming capability and working up an estimate. 

-Jake

[peteski]

Have you used a flywheel puller? i suspect that you havent, cause it takes a bit of force to pull the flywheel off the shaft of a motor, therefore you would still have to use force to put one back on.

I guess we can spar about this forever.  You keep missing the point that Max wanted to make the Tungsten flywheels hole slightly oversize.  So yes, you need a gear puller or some other brute force method to pull the original brass flywheel off the shaft, then you simply and easily slip the new tungsten flywheel onto the shaft using some Loctite to keep it in place.

And yes, I have pulled flywheels and worms off motor shafts using a gear puller or other home-made solutions.

oh and secondly a unbalanced pinion gear can affect alot of things... like oh i dont know wear and tear of gears... and hmmm the bearings in a motor...
go ahead ask me how i know....

You are absolutely correct. That is why I think that a set-screw in a flywheel is not a good idea.  There are different degrees of unbalance.  As I mentioned before, there will not be much of an imbalance on a pinion gear which has a set screw in a small diameter collar.

But you win - since you obviously own some sub-miniature tungsten-carbide taps (which I do not own), go ahead and use set screws on your tungsten flywheels. I'm sure the flywheel will work perfectly. 

[mmagliaro]

I like the stacked washer idea! 

[nkalanaga]

Mike:  My comments on the dangers of machining uranium were based on reading about the Manhattan Project in high school.  Good to have some confirmation!

I wonder if my old high school still has those books in the library?  Several had enough details, including diagrams, that anyone with the uranium or plutonium could have built a bomb.  The uranium one is very easy, if all you want is a relatively inefficient boom.  I can't imagine a school library being allowed to let teenagers read that today.

[peteski]

I wonder if my old high school still has those books in the library?  Several had enough details, including diagrams, that anyone with the uranium or plutonium could have built a bomb.  The uranium one is very easy, if all you want is a relatively inefficient boom.  I can't imagine a school library being allowed to let teenagers read that today.

Maybe not, but I'm sure if you look (and probably not too hard), you can find that info on the Internet (plus lots of other info on making all sorts of nasty devices).  Who reads printed books anymore?

[u18b]

Maybe not, but I'm sure if you look (and probably not too hard), you can find that info on the Internet (plus lots of other info on making all sorts of nasty devices).  Who reads printed books anymore?

Haha.  There is no way I would google something like that.... and not expect someone from homeland security showing up at my door.

Now back to trains.

[nkalanaga]

I know it can be found on the Internet, as well as simpler ways to make big booms, some of which would probably do about as much damage.  It would be interesting to see if the books have survived 40+ years of wear and tear, or if I was the last one to read them!

Surprisingly, they also had a large sci-fi section, which I read through in the three years I was there, as well as the science section, and a lot of general fiction.  A very well stocked library.  I've seen less selection in public libraries.

[SandyEggoJake]

Max,

So I've not been impressed by the responsiveness to my RFP for W washers from the local company, but have since located one in China that already produces W washers in standard sizes and is willing to do a custom lot of 10mmODx1.5mmIDx1mmThick.  They claim they have already produced such a custom washer (as balance weights for several 1921 Rolls Royce wheels).  Their tolerance is typically +/- 0.1m, so it may require some post production selection for those suitable for flywheels.  Of course, as a stack of washers, some of the inherent imbalances might be adjustable. 

They are asking for a timing estimate (when needed by) which they suggest may impact pricing.  As my project is still on the drawing board, I have no urgency, but do you?

-Jake

[mmagliaro]

Jake,
I do not have any urgency for this.   I started this thread just to show my calculations and to show that I came to the conclusion
that it was probably not worth it because the increase in flywheel action to be gained wasn't worth the trouble.
I was not thinking about the benefit of the added weight in the engine, however.

+ or - 0.1 meter would be horrible.  They can't be serious.  They have to be able to make a 10mm washer more accurately than that.
My guess is that spec is meaningless and they are used to making things much larger than a 10mm washer.   You may as well
get a price from them, and we'll see how bad it is.  If it's reasonable, I'd still be up for buying a stash of them.

[SandyEggoJake]

my typo. 

+/- 0.1 mm. 

[mmagliaro]

my typo. 

+/- 0.1 mm.

Ah good.
Even so, in a 10mm flywheel, that's 1% error.    Is that good enough for a flywheel to avoid vibration?

[SandyEggoJake]

No idea.  Would require some testing.  And of course, by using stacked washers, some vibration might be able to be countered. 

[peteski]

Ah good.
Even so, in a 10mm flywheel, that's 1% error.    Is that good enough for a flywheel to avoid vibration?

I'm not a mechanical engineer but I try to play ine on TRW. 
Any imbalance will result in vibrations. How severe?  That depends on a several factors. Things like the resonant frequency of the mechanism and the the rpms.  Even small vibrations which might not be detrimental to the operation might be produce vibration which results in annoying sounds.

That is why flywheels in general needs to be as balanced as possible. Even the factory ones turned out of brass (which should be well balanced by design) are sometimes tweaked at the factory by drilling small holes in them or adding some sort of a putty to them. Even motor armatures (which by themselves are flywheels too) are often tweaked to be balanced by girding some of the material or by adding putty weights).

[JoeD]

I know where we can get a whole bunch of it

Since we are crossing into esoteric elements territory, why not go right right to depleted Uranium, a-la Jim FitzGerald?     Well, actually I am semi-serious.