I have never attempted a blog before, GSWR101s thread seems to have stirred up considerable interest in the practical side of 21mm gauge modelling so I though I would write up my experience with rolling stock conversions and leave the locos to a later date.
I first tried my hand in 21mm in the early 1980s but it took about 10 years to develop the necessary experience to achieve half decent results.
I was an MRSI member, some of the more influential members were starting to modify or scratchbuild Irish locos and stock but most of the more senior modellers were interested in the Big Four, American or Continental railway.
At the time the standard of British rtr just did not compare in detail or running quality with Fleischmann, Trix, Liliput, Marklin or even Athearn.
Having a contrary nature scratchbuilding and doing your own thing appealed more than following the crowd and my pocket did not stretch beyond buying plaasticard and the odd Lima Loco.
There was very little information or models available at the time Tim Cramer published a series of articles and drawings in Model Railways, the occasional drawing and article appeared in the Modeller and Constructor.
Around this time articles on Richard Chowns O Scale WLWR layout, Iain Rice's series on Tregarrick and the original Advaoyle prompted me to have a go in 21mm.
Little or no information was available on wheel or track standards at the time Tim Cramer quoted a 19.5 wheel B-B dimension in an article in the moddeller in the 1970s, David Malone produced a detailed how to article on modelling to S4 Standards in Practical Model Railways.
I work to use a set of TMD 21mm gauges with a B-B of 19.5 with EM profile wheel sets although 19.3 is recommended to deal with Romford/Jackson and other coarser wheel profiles allowable in EM.
There were few suitable kits and no rtr models available, Terry McDermott introduced a MGWR tank loco kit and the Model Wagon Company Ardrossan a GNR(I) cattle wagon. Des McNally started to introduce the range of MIR whitemetal kits of then contemporary wagons a bit modern for the late 1950-60s period.
My first train was made up of an ex MGWR Achill Bogie with a Lima 4F tender drive, & a pair of ex MGWR coaches all in plastciard very pretty but it did not run very well or even stay on the track.
Suitable axles and suspension units were not available at the time, wheel sets ran in home made inside bearings, wheels were simply pushed out on their axles to the correct Back to Back.
Most of my locos and stock are fitted with EM or NMRA RP 25 profile wheelsets, however, I have a few vehicles with the very good solid brass Jackson wheels supplied with Parkside kits, Bachmann and an odd profile brass wheel supplied with PC Coach Kits, thanks to John Rednup I cleared out Puffer's stock of these wheels at a substantial discount in 1988.
For me the big break through was Mike Sharmans huge range of loco, bogie and tender wheels all supplied with extended axles which the user cut to length.
I could at least build 21mm locos that could run even if they looked pretty bad
Suitable coach and wagon wheels were still a major problem although Alan Gibson advertised 21mm wheel sets with 28mm axles, he does not appear to have been prepared to supply, however Ultrascale supply their excellent wheels in 21mm to S4 or EM tyre profile.
Another way around the problem is to cut and sleeve a standard 26mm axle with 2mm ID brass tube from Eilleen's Emphorium.
Hornby Stanier bogie with .060" bolster, PC wheelsets axles sleeved with 2mm brass tubing
The nasty bit Dapol solebars packed out with 1mm plasticard
The break through in 21mm modelling came with the introduction of by the S4 Society and Studio Scale Models or suitable W Iron assemblies.
MJT produce a very usefull inside bearing unit originally designed for fitting compensation to RTR Models http://www.dartcastings.co.uk/mjt/2291.php
Ratio LNWR open converted to 21mm with MJT inside bearing units I think the wheelss are Gibson or Magib OO or EM wheelsets pushed out to a 19.5 Back to Back
MJT also produce a coach compensation unit that can be adjusted out to 21mm gauge.
MJT CCU packed out to 21mm