Small-Scale Live Steam

Making Model Locomotive Wheels

Gauge 1 Model Railway Association Wheel Standards

The Gauge 1 Model Railway Association of the UK has formulated standard wheel measurements which aid reliable running of (1:32 scale) engines operating on 45mm track. The diameter of the wheel is of course dependent upon the locomotive in question.  The specifications below show the G1MRA standards for wheels and axles.  Corresponding track standards are also available from the G1MRA.

While these standards are for 1:32 scale wheels, they are also applicable to other scales operating on gauge 1 track (i.e. 1:225., 1:20.3, et al.).  The "IF" measurements are for use with "finescale" wheels.  For the larger scales, the flanges and treads come closer to representing actual scale tread sizes.

I would recommend that those turning wheel castings to a finished profile consult an article in Model Engineer magazine (Vol. 161, No 3832, p. 282) entitled "Wheel Turning". Author Barry Applegate describes a prodecure for assuring that all the diameters on the wheel are concentric after turning. (This is not as easy as it would appear before you have done it!)

Chart showing G1MRA axle and wheel measurements.  

This article is from a handyman's magazine from the 40's. The scan is courtesy of Robin Corsiglia, collector of toy steam boats and stationary engines.

Figs. 2-4, showing the plan and elevationof the mold, and the turning setup in a 4-jaw chuck. Molds to Cast Model-Locomotive Wheels

MODELMAKERS who build locomotives need not go to the expense of purchasing the wheels, Fig. 1, if they cast them in these brass molds, which can be used repeatedly. The molds shown are not dimensioned to a particular scale, but by following the instructions you can make them to any desired scale. All you need is two small pieces of brass, one a little thicker than the wheels to be cast to serve as the mold, and the other to serve as a cover.

First, chuck the thick piece in a lathe and turn it to form a profile of the wheel to be cast, Fig. 3. Turn the depression for the hub, tire and tire flange, and then turn the rest of the profile to equal the thickness of the spokes. Be sure to allow a 2-degree draft or taper on the hub and tire-flange depressions. This is necessary to assure easy removel of the casting. It may be necessary, after turning the hub depression, to use a mill to elongate it to form the crank lug.

The next step is to cut segments and rivet them in the mold to form the spokes, Fig. 2. These can be cut from brass on a jigsaw, using a jeweler's blade. Tilt the saw table at a 2-degree angle to taper the segment edges to get the necessary draft. Now, cuts or scores should be made in the face of the mold from each spoke position as indicated by the dotted lines in Fig. 2, to allow air to escape when pouring the metal.

Section plan of assembled mold.  The upper half of the mold is quite simple to make. It is fitted with four pins to engage holes in the lower half of the mold. A tapered hole is bored out on the lathe to form a hub for the inside of the wheel, and is continued right through the plate by drilling, Fig. 4. This hole is for pouring and should be countersunk on the inside to permit easy removal from the casting. Before using the mold, it should be heated slightly and smoked well on the inside.

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Copyrights owned by the respective authors.  Compiled by: Vance R. Bass. All rights reserved.  Please use any and all information contained herein for your hobby enjoyment. If you're going to make money from it, talk to me first.

Last updated: 14 Feb. 1999.