Stephen Poole Wheelsets

[Il Grifone]

A basic question.

 

Am I correct in thinking these have aluminium tyres and are best left alone?

 

Leaving aside conductivity, I believe aluminium is good at picking up muck?

 

Many thanks in advance!

Edited October 24, 2020 by Il Grifone

[Michael Edge]

They are aluminium, completely useless for pickup purposes but they are fine on tender locos (with pickup from the tender wheels of course) and I still have quite a few locos fitted with them. They were very well made, concentric and easy to fit on the axles, if they had had the sense to use steel or n/s they would have been excellent. The quickly collected muck does soon turn into traction tyres so the haulage capacity can be immense.

[5050]

Originally launched in a blaze of glory extolling their excellent electrical conductivity characteristics.  In practice it was soon discovered that other less beneficial characteristics quickly overshadowed the conductivity one.  Like Mike says, they look good etc. - but...........................

[Michael Edge]

Aluminium is indeed a very good conductor, however aluminium oxide which forms very quickly is a pretty good insulator. This was in fact the principle behind the Peco Insulaxles - if anyone else remembers these.

[melmerby]

I had a set of these for motorising an Airfix Prairie.

They look like Alan Gibson driving wheels but fitted with ally tyres

When working () the loco would travel down the track in a shower of sparks!

I tried resurrecting them a few years back but I ended up binning them. they are now in the might, just might come in useful box.

[Bucoops]

47 minutes ago, Michael Edge said:

Aluminium is indeed a very good conductor, however aluminium oxide which forms very quickly is a pretty good insulator. This was in fact the principle behind the Peco Insulaxles - if anyone else remembers these.

 

My house was built on the cheap in the 60s - the BT phone line is aluminium cored instead of copper. Good conductor, but brittle. Amazingly my internet connection over it is very stable considering it's 50 years old. 

[melmerby]

As a comparison, the resistivity of some commonly used metals

 

Silver has a resistivity of about 1.6 (x10-6 Ω·cm)

Copper has a resistivity of about 1.7 (x10-6 Ω·cm)

Aluminium is 2.3 (x10-6 Ω·cm)

Brass is 3.9 (x10-6 Ω·cm)

Steel is 13-22 (x10-6 Ω·cm) varying on C content

Nickel silver is 28 (x10-6 Ω·cm)

Stainless steel is typically 90 (x10-6 Ω·cm)

[Bucoops]

1 minute ago, melmerby said:

As a comparison, the resistivity of some commonly used metals

 

Silver has a resistivity of about 1.6 (x10-6 Ω·cm)

Copper has a resistivity of about 1.7 (x10-6 Ω·cm)

Aluminium is 2.3 (x10-6 Ω·cm)

Brass is 3.9 (x10-6 Ω·cm)

Steel is 13-22 (x10-6 Ω·cm) varying on C content

Nickel silver is 28 (x10-6 Ω·cm)

Stainless steel is typically 90 (x10-6 Ω·cm)

 

Interesting - being that Markits wheels (when you can get them ;)) have changed to Stainless tyres. I don't suppose it makes much of a real world difference but that's quite a jump.

[melmerby]

7 minutes ago, Bucoops said:

 

Interesting - being that Markits wheels (when you can get them ;)) have changed to Stainless tyres. I don't suppose it makes much of a real world difference but that's quite a jump.

The ones I bought a few weeks ago (yes, I did find some of the size I wanted!) didn't look any different to those bought years ago, but they could have been old stock.

 

Here's the aforementioned Stephen Poole wheels.

Compared to Markits and Gibson wheels the crankpin boss is smaller.