Member postings for Chris Kaminski

Thank you

I just wasted half an hour looking for "look-now-further" on ebay...🤬

It is actually:

Edited By Chris Kaminski on 15/05/2022 16:15:30

Have a look here:

https://www.mig-welding.co.uk/forum/threads/hofmann-dividing-head-lubrication.99259/

thank you @ br

Like I said in my reply to IanT, things have moved on since the days of Basset-Lowke and Bowman.

ACE locos are electric? not live steam? (unless I am missing something) so not really like for like comparison to what I am talking about?

Yes, you are right bushes are possible.

The main argument against them in live steam model is the one Eddie Cooke offers:

"...Hardened eyes will outlast umpteen bushes ..."

Now, I guess he is right (I do not doubt his experience and expertise), but I am querrying the effect of case hardened coupling rod eyes on soft crankpins?

thank you @IanT

I am not questioning "Gurus" - just trying to understand reasoning ...

Like yourself, my thinking is that coupling rods would be easier to replace/re-bush than replacing crankpins,

Hence my question.

Of course LBSC is not really a good recommendation - his designs (especially in smaller scales)

whilst practical, were overscale, oversize, over loading gauge and would not be acceptable today (things have moved on since his days...).

On the other hand, chaps like Clarry Edwards or Eddie Cooke have great record of building many beautiful live steam models in gauge O, so I do not doubt their expertise... just trying to understand how does it work.

In bigger gauges coupling rods are bronze bushed and run on steel crankpins.

Wear (when it happens) is to the bushes, which can be easily re-bushed when needed.

In gauge O there is no space for bushes.

LBSC makes coupling rods from "steel strip" and says:

"...There is no need to bother about bushing such weeny rods for the first kick-off....If in the course of time they should wear and begin to rattle, they can easily be taken off, drilled out and bushed with a scrap of bronze in a few minutes..."

Evans suggests that crankpin holes in the coupling rod should be case hardened (with silver steel crankpins).

Eddie Cooke says:

"...I case-harden as the fitting of bushes would require a large hole to be drilled, which would leave very little metal round it. Hardened eyes will outlast umpteen bushes and are easier to make..."

Clarry Edwards, similarly says:

"...Crankpins are silver steel and coupling rods filed from 3/32" mild steel... the ends sre case hardened..."

So in summary the recommendation seem to be:

silver steel crankpins, mild steel coupling rods (no bushes) with case hardened ends

My question is about wear of such a combination?

Will the cranpins wear before coupling rods?

Would it be better to harden crankpins as well?

I realise that majority here will have experience of bigger gauges, but it's worth asking the question...

Thank you Jeff,

That would have been the "best engineering practice" way of doing it.

Whether it is feasible and whether it is worth bothering with, is another story...

Well spotted Clive

on page 75 of 1983 edition of his "The Model Steam Locomotive" he says:

"...Sometimes gaskets made of some kind of heat-insulating material are used between cylinder and frames, to reduce as far as possible heat loss from the cylinders. A sheet steam packing material such as Messrs James Walker's "Walkerite" or "Golden Walkerite" is ideal for this purpose..."

So, I guess mystery solved and my question is answered

Yes, gasket materials are used where appropriate and needed...

but not for use between frames and cylinders?

@ Nick

Cynic in me tends to agree with your views about Martin Evans's mistakes

but I must give him credit were it is due - elsewhere in this series he acknowledges a mistake in the drawings of tranverse stays in the boiler "...Slight slip by draughtsman!..."

I guess that is the thinking behind it.

Having said so, the real gauge O live steam experts like Clarry Edwards and Eddie Cooke (who BTW designed and built many more locos in this gauge than Martin Evans) never mention any thermal insulation of cylinders...?

As for "...'gasket' material thickness is probably vital to stop 'clashing ' somewhere..."

that cannot be so - simply increase the cylinder body by 1/64" instead of adding 1/64" gasket and you will avoid any "clashing"

no such hope - both his drawings and texts (usually) leave a lot to guess

at least I couldn't find it anywhere...

Thank you guys,

@ David G.

Heat transfer prevention seems the only plausible explanation, but I have never seen it in any other design (whether in G0 or G1) so I am puzzled as to why Martin Evans thought it "important" ?

@David M.

Yes, James Walker is the original manufacturer of "Golden Walkerite"

"...In 1882, Scottish engineer James Walker founded a company
to sell engineering accessories to ships in the Port of London.
...and followed this with Golden Walkerite® high
pressure jointing..."

I guess it is no longer available because of it's asbestos content...

Question for me is why use it, though?

and has it been used in any other loco design?

Edited By Chris Kaminski on 15/02/2021 08:28:19

Looking at Martin's ME articles (1969) about building Royal Scot in gauge 0, I am puzzled about the use of Walkerite sheet joint between frames and cylinders.

Never seen anything like this before?

Can anyone, please explain what is it for?

Chris