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* Building the LMS Stanier Black 5

* Build GWR dia. AA11 "Toad" from a kit

* Machining Steel Wheels

Wheels

Classically speaking G3 wheels were made from molten iron which was "puddled" into moulds. This is a slow and expensive process nowadays as there are few iron works and most modern wheels are made from glass fibre with a steel rim pressed onto them. Cutting a classical wheel requires a lathe and either HSS or TCT tools. Which you use is very much dependant of the power of your lathe motor and personal choice. As a guide, small power lathes (<100w ) have to use TCT tools. The process is very simple, but very messy. The casting is first deep cut with a TCT tool to get past the layer of iron which contains the casting sand to the soft iron below. Some people prefer to change over to HSS tools at this point as it gives a smoother finish. You may cut with or without a coolant stream.

These are some of the wheels supplied.

The National 2.5 Gauge Association DIAMETERS IN FRACTIONAL INCHES

LocoSpokesDiameterCrank PinP/NNotes
AUSTERE ADA 2 1/2 AD1DRIVER AND COUPLED
BRITTANIA203 1/4BETWEENBRT DDRIVER
BRITANNIA203 1/4BETWEENBRT CCOUPLED
4MT203 1/4BETWEENBRT CCOUPLED
4MT203 1/4BETWEENBRT CCOUPLED
SECR C162 5/8 CLDDRIVER
SECR C162 5/8 CLCCOUPLED
SR Q1BOXPOK2 7/8 Q1DRIVER AND COUPLED
STIRLING SINGLE244 1/4BETWEENST1DRIVER
US AUSTERITY132 1/2 US5DRIVER
US AUSTERITY132 1/2 US6INTERMEDIATE COUPLED
US AUSTERITY132 1/2 US7LEADING AND TRAILING COUPLED
LMS 4P TANK183BETWEENW6DRIVER AND COUPLED
EAGLE203 3/8 W10DRIVER AND COUPLED
FLYING SCOT203 1/2 W15DRIVER
FLYING SCOT203/12 W16COUPLED
BLACK5193 1/8 W38COUPLED
BLACK5193 1/8 W38COUPLED
EVENING STAR152 5/8 W53DRIVER
LYME REGISBOXPOK3 9/32 WC1DRIVER AND COUPLED

Alan Headech castings range -now owned by N2.5GA DIAMETERS IN DECIMAL INCHES

LocoSpokesDiameterCrank PinP/NNotes
NER K91.575BETWEEN4006 
LYR PUGSOLID1.575 4710 
LSWR B4101.969INLINE5210 
 122.126BETWEEN5312SSMALL CRESCENT
 122.126BETWEEN5312BLARGE CRESCENT
NBR G102.224INLINE5610 
 122.224BETWEEN5612HEAVY BLOCK
LNWR122.362BETWEEN8012H SPOKE
 142.441INLINE6114MEDIUM CRESCENT
 142.519INLINE6314MEDIUM BLOCK
 162.716INLINE6916N 
 162.716INLINE6916SSMALL CRESCENT
 162.716INLINE6916LLARGE CRECENT
 162.716INLINE6916AOFFSET LEFT+
 162.716INLINE6916BOFFSET RIGHT+
S15182.933INLINE7518N 
 182.933INLINE7518LLARGE CRESCENT
 182.933INLINE7518SSMALL CRESCENT
SR N182.933INLINE7518N 
 182.933INLINE7518AOFFSET RIGHT+
SR U203.189BETWEEN8120N 
SR H15203.189BETWEEN8120N 
GWR HALL203.189BETWEEN81CBLOCK CRESCENT
 203.307INLINE8220N 
 203.307INLINE8220LLARGE CRESCENT
 203.307INLINE8220SSMALL CRESCENT
 203.504INLINE8920N 
 203.504INLINE89200SSMALL CRESCENT
 203.504INLINE8920LLARGE CRESCENT
 203.504INLINE8920AOFFSET RIGHT+
SR KA223.523BETWEEN8922N 
SR V223.523BETWEEN8922N 
SR LN223.523 8922SDMED. CRESCENT
 223.523BETWEEN8922N 
LNWR203.642 9524SMALL CRESCENT CIRCULAR BOSS
 243.740BETWEEN9624MED. CRESCENT
 224.055 10122SMALL BLOCK
 224.055BETWEEN10222SMALL BLOCK
 224.134INLINE10522SMALL BLOCK
 81.437 3508 
 101.437 3501LBSC DESIGNS
 SOLID1.437 36D1 
 81.653 4008 
 91.614 4109 
S15101.614 4110 
 121.653 4212 
 101.712 4410 
N15101.890 4810 
 121.949 4912 
 101.968 5110 
 122.165 5412 
 142.421 6014 

GLR KENNION CASTINGS FOR 2 1/2 INCH GAUGE DIAMETERS IN DECIMAL INCHES

LocoSpokesDiameterCrank PinP/NNotes
 203.625 K1A
 162.75 K2B
 142.5 K3B
 122.25 K4B
 SOLID2.0 K5B
 121.875 K6C
 121.875 K7C
 101.625 K8D
 101.5 K9D
 SOLID1.437 K10D
 SOLID1.375 K11D
 121.875 K12D
  • A - crescent balance weight for drivers
  • B - flat crescent balance weight for drivers and coupled
  • C - no balance weight for tenders
  • D - no balance weight for engine bogies

Walsall Model Industries -Castings for Gauge 3 DIAMETERS MM

LocoSpokesDiameterCrank PinP/NNotes
 837-44 T18073"1'BOGIE AND WAGON
 1039-44 T18183"3'BOGIE AND TENDER
 1249-55 T18414'0" TENDER
 1665-71 T19095'3" DRIVER

Note: the T1909 driver casting is designed to take up to a 1/2 inch throw.

Mark Wood Wheels -Castings for Gauge 3 DIAMETERS IN G3 SCALE FEET AND INCHES

LocoSpokesDiameterCrank PinP/NNotes
LBSC TERRIER12 INLINEX34' DRIVER
 12 INLINEX44' COUPLED
LMS DUCHESS9  X353' LEADING
 21 BETWEENX376'9" DRIVER
 11  X364'3"TRAILING
 12  X384'3" TENDER
LMS JUBILEE10  X1343'3.5" LEADING
 21 BETWEENX1536'9" DRIVER
 12  X384'3" TENDER
NER H10 INLINEX1523'6.25" TENDER

Modern outline locos such as diesels and electrics normally have disc wheels which can be turned from slices of steel bar stock. This is true of wagon wheels and making a 3 hole wheel is very simple. There are several advantages to this as the bar will have no cracks or casting faults and the steel will be easy to cut as there is no sand crust to cut through. See the article in Part E Workshop practice.

This is a Guide to Wheel Sizes used by DEMU EMU and Diesel Stock.

However the problem begins when the loco of your dreams has a "strange wheel"...

The most common of the "strange wheels" is the US BoxPok (box spoke) wheel. This is not like the Bulleid-Firth-Brown wheel that we are used to seeing on a Southern Railways "West Country" -although the BFB wheel has come to share the same name. There are no castings or easily adaptable ones for this -you will just have to make it. The original was made in cast sections that were bolted together. It is possible to "fudge" a BoxPok using a disc of steel that you drill the correct size holes into and then mill between them to produce the tear drop shaped holes into. By using off set centring in the lathe it is easy to cut the crescents from the surface. (replaces page)

The Bulleid-Firth-Brown wheel was made as a complete steel casting. It is available as a cast iron wheel (see above) but it is fairly simple (if tedious) to make. Again this involves drilling holes through the slice of bar and then milling the teardrops. (replaces page)

The next wheel is the US "Scullin" double disc wheel. This is actually very easy to make as the slice of steel is given a slight cone on the outer surface. The characteristic of the Scullin are the number of holes drilled "through" the two discs. These form four points of a pentagon. The crank pin occupies the space between the bottom holes, i.e. there are two before and there are two holes after it. In the original the driver and coupled wheels would have lead weights between the two faces opposing the crank pin. (replaces page)

The next wheel is the SCOAP. This is the last major design in steam locomotive wheels. This has U profile steel spokes instead of oval cast iron ones. The base of the U faces inwards, (ie towards the loco,) thus it looks like the wheel has deep channels cut into the spokes. These were common on Colonial locomotives and locomotives made by Vulcan. (replaces page)

The last "strange wheel" is commonly referred to as a "snowflake wheel". These have to be made by hand from cut pieces of steel bar. The mathematics are simple, the construction amazingly hard... At high speed the spokes on a wheel can vibrate, this can lead to destructive cracking. Edwardian thinking was to make the spokes short, so that the frequency would never be reached in practice, and in this -they were right. A snowflake wheel consists of a central hub with six thick radiating spokes, each spoke then splits into three thin ones at 60 degree spacing and the now eighteen spokes touch the rim of the wheel in eighteen equidistant places... (replaces page)


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Page last modified on August 22, 2018, at 05:49 PM