Re: pros and cons of brass bearings?


midrly <midrly@...>
 

When I look in the otherwise excellent UK model rail magazines like Model Rail and Model Railway Journal (MRJ authors are as particular about UK steam-era freight rolling stock as we are about North American freight cars--maybe more so), I wonder why Tichy hasn't sold a container or two full of their nylon journal bearings to the Brits instead of those brass journal bearing ("oil box") insert devices that they seem so fond of...

Steve Lucas.

--- In STMFC@..., "Rob Kirkham" <rdkirkham@...> wrote:

Thank you for explaining Denny. I hadn't realised the friction would be
worse with brass bearings.

Seems the only remaining purpose might be to add wear tolerance in RP'd
trucks.

Rob

--------------------------------------------------
From: "dennyanspach" <danspach@...>
Sent: Saturday, December 15, 2012 11:15 AM
To: <STMFC@...>
Subject: [STMFC] Re: pros and cons of brass bearings?

The coefficient of friction between the steel and/or brass axle ends
(journals) and cylindrical brass bearings is greater, probably by a
significant degree, than that between the same axle ends and the
ubiquitous engineering plastic side frames that we mostly deal with these
days. Also, it is pretty uncommon these days to have good wheel sets that
have cylindrical rather than conical axle ends.

The Tichy nylon bearing inserts are pretty good, and are designed to offer
better rolling and wearing characteristics in truck frames made of soft
styrene. The downside is that such use commonly results in either trucks
that with the inserts are too narrow to accommodate almost any commonly
available axle sets, or if they do fit, the truck is far too wide to begin
with.

Athabaska made some very fine low profile conical brass bearing inserts
designed for styrene E&B passenger trucks, if I recall; and Reboxx also
once made some excellent engineering plastic bearing inserts.

All in all, IMHO bearing inserts have little application in the present
world of current freight and passenger trucks, but have found limited use
with imported brass trucks, and the few trucks still being made of soft
plastic.

Denny

Denny S. Anspach MD
Sacramento







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