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1:22.6, Gauge 3
LMS and BR Driving wheel.

5′ 8″ diam., 18 oval spokes, vee inner rim, apparent tread 3½″, tyre width 5 3/8″.
Hub 16″ face dia, level with the tyre, pin between at 14″.

Sources: 2-6-4T 4MT No 80151 at Chappel, 2-6-0 4MT No 76079 at Llangollen, measured direct in 1995.

Castings: 76.4 mm tread dia., 68.4 i/d., hub level with the tyre, pin at 15.73 mm.

Gauge 3 loco set prices . Casting prices and stock

Scan of a casting in a sets for BR 4-6-0 4MT . BR 2-6-4T 4MT

Suitable for the Gauge 3 Society 2010 minimum tyre width of 6.8 mm, or the earlier standard of 8.0 mm.

Laser-cut balance weights, steel, 1 mm thick - scroll down to the bottom.
Scan of casting X73
Scan of casting X73 machined
With a G3 Standard flange

Cross section diagram of casting X73

Cross section diagram of casting X73 with 6.8 standard tyre width
Turning diagram marked out to show the work-holding steps as used for the form tool method for a tyre 6.8 mm thick and with a 2 mm deep flange.

1. mount the casting with its back out and cut the small step on the back.
2. with the front out,
  cut the larger step,
  face the hub so you leave the whole top face just planed over.
    (cut a little high, then another 1 or 2 cuts of 0.01 mm until it looks right).
  face the tyre level with the hub.
  bore the centre just under the size of the final reamed diameter.
3. with the back out, face the back to your chosen the tyre width.
4. mount the casting on a slightly loose (by diameter) mandrel between two discs, centre it, tighten up, and make the final cut with a form tool.

Mid  weight
Outer weight

Laser-cut balance weights, steel, 1 mm thick.
Model Engineers Laser part No. 11399, Driving wheel, £1.69 each; part No. 11400, Coupled wheel £1.68 each. (£20.20 per set).
These do not fit tight against the rim, but about 1 mm away with the ends on the centre lines of the spokes.

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27 Mar 2013