36 replies to this topic

[Mr. M]

The material properties of these are similar. What are the implications of building wire frames from one or the other?

[Gator Bob]

Chris,

 

SS hollow tubing vs. solid steel wire?

Or solid stainless 'wire'?

[DOCinCanton]

I would expect that what we call "piano wire" (which we use today to build IRRA^TM  chassis) is a 300 grade stainless steel. What would be important to me is the Young's modulus comparison of the two wires.

[Marty N]

For the same "weight" of material the tubing by nature of the larger diameter will be stiffer. In contrast, IF the tube and wire are the same diameter the tube is lighter and not as stiff.

 

As far as piano wire vs SS wire of like diameters such as TIG wire, piano wire has a better "memory" and a higher yield point. Takes a hit better. SS is slightly lighter...ever so slight and doesn't corrode.

 

For what 2 Cents is worth.

[Ramcatlarry]

and of course SS is harder to solder, usually requiring the higher acidity flux .....

[Gator Bob]

Doc,

If you want to get technical.... lol

 

Hooke's Law might be more applicable.

 

The wire spring characteristic is changed through altering the tensile strength during the soldering and bending processes.

 

Also, keep in mind that a chassis flexing creates heat and the fact that it becomes the motors heat sink that will alter the elastic potential energy as it varies with temperature and the resultant macroscopic vibrations will effect performance of an isotropic component such as a chassis rail. 

 

 

[DOCinCanton]

Bob, What you described is NOT Hooke's law.

 

Also, the little amount that the chassis flexes will only result in an almost unmeasureable amount of heat. Never enough to change the elastic modulus of the steel wire. The motor bracket and the attached steel rails will heat up more from the motor than any flexi could possibly create.

[Gator Bob]

Did I get that wrong?   

 

I thought it was the 'Law of"

Strain/stress tensors and torsional resistance of a wire.

 

Kinda like the front 'springs' in a Mopar  

[DOCinCanton]

Bob, are you talking about the True stress or the Engineering stress?

[Gator Bob]

I'm talking about cutting class today and the stress of trying to jerk the front wheels off the ground in a SuperBee SixPac.... lol

[DOCinCanton]

Chris, getting back to your original question: Assuming that you are talking about solid wire (not tubular rod) the only implication I can think of is in the manufacturing of each type of wire. When we bend straight steel wire into a 90 degree bend, we have greatly exceeded the porportional limit of the wire. So the ductility of the wire is important. So the source of the wire is important and how it is manufactured. I know from personal experience that the wire I buy from Bill in those three foot lengths are ductile enough. I have gotten piano wire in the past that snapped when I tried to make a 90 degree bend. 

[MSwiss]

The material properties of these are similar. What are the implications of building wire frames from one or the other?

I was surprised awhile back, while at an Ace Hardware, to see K & S had stainless steel rod.

 

IIRC, I bought a length of 3/32" to try for jig axles.

 

As far as for chassis rails, I don't see the benefit.

 

Along with probably not soldering as well, piano/music wire has proven itself as a good slot car chassis material.

 

A nice blend of strength and give.

 

That said, I don't really know the specs of the K & S stainless.

 

But if it is less prone to bend, that's probably not necessarily a good thing.

 

Just like when I tried A2 air hardened, tool steel, for wing car chassis, stuff that won't bend as easy usually will snap.

[Mr. M]

From the K & S web site piano music wire is ASTM 228 and stainless 302 ASTM 313. This is what they sell on the rack.

Piano wire density 0.284 lb/in3., tensile strength 230 to 399 mpsi, modulus elastic 30 mpsi, modulus torsion 12 mpsi.

Stainless. 0.286. 125 to 325. 28. 10.

[Bill from NH]

Chris, piano wire is easier to work with & it's cheaper than than stainless steel. The stainless will make better chassis jig pins.

[Fast Freddie]

What about stainless wire for front axles? They shine up really nice and for the most part are rust free.

[Gator Bob]

What about stainless wire for front axles? They shine up really nice and for the most part are rust free.

 

Fred, for Retro or Flexi use?

[DOCinCanton]

For flexi, you would use a tube; for retro, you must use a solid steel axle, any grade of steel is acceptable I believe. Its the rules!

[Marty N]

http://www.vaillyavi... Wire _web_.pdf

[Gator Bob]

http://www.vaillyavi... Wire _web_.pdf

 

Thanks Marty ..

[DOCinCanton]

Good info.

[Marty N]

Your welcome.

[Fast Freddie]

I actually ment Retro on the stainless front axle. I found some 3/32 stainless rod and was going to give it a try.

[JimF]

FWIW................and that's probably not much.

 

I had some a while back and messed around with hinge tubes and such using it. It seemed to me that the SS wire bent more easily than comparable PW. Of course, I don't know what kind of SS wire it was and there are certainly a bunch of different kinds.

 

However, there are maybe a couple of interesting possibilities about SS wire.

 

One is that since Amazon has gutted many of the cool sizes of PW from what used to be "small parts inc", there are still a lot of odd and "in between" sizes available in SS wire.

 

The other is that it might turn out that some grades of SS wire may be sort of in between the properties of bronze and normal PW. This might in turn give you some of the damping qualities of bronze/brass while retaining some resistance to bending that is the achilles heel of the bronze/brass.

 

Then again...........................

[Gator Bob]

I think it might be softer than PW but if it is lighter and not used on an open wheel car it could be an improvement.

[DOCinCanton]

Chris, did you get an answer that you wanted?