The 3/4" scale, 3-1/2" gauge USRA D-30 class 0-6-0 switcher, designed by H.J. Coventry 1949, as illustrated in The Miniature Locomotive Magazine in 1954.
A front view of the 3/4" scale USRA switcher being built in 2011 by George W. of Canada.
The 3/4" scale USRA 0-6-0 switcher as being built by Jack Bodenmann of California. Critical castings were made available for this engine in 2008; the first time they had been available in some 40+ years. Jack is building the first known example to be built in those 40+ years.
Here you will find a nearly complete set of "rough castings" for the coal-fired, 3/4" scale, 3-1/2" gauge H.J. Coventry D-30 class 0-6-0 USRA Switcher, as designed by Mr. Coventry in 1949 from official Baltimore and Ohio Railroad company blueprints.
Castings and blueprints for this live steamer were first made available about 1950 and advertised in "The Live Steamer" magazine published by George Murray in Connecticut. Its construction was then serialized in "The Miniature Locomotive" magazine in 1954, and later in "The North American Live Steamer". Castings have been unavailable commerically since the 1960s.
The castings are brand new iron, bronze, and aluminum; and are poured at commercial foundries in New England, USA. They are EXACTLY the same as those that were supplied by Mr. Coventry some fifty-plus years ago. You cannot tell the difference.
Hand pump and injectors standard; a VanBrocklin duplex water pump (steam powered) can be mounted on the left side of the locomotive (drawings available); and a non-Coventry axle pump can be built and custom-fitted by builder if desired 4-1/2" OD copper boiler; silver soldered. Can be rolled from sheet, or seamless pipe can be purchased from suppliers in the United Kingdom
Machinery Requirements: 9" (or larger) lathe, small to medium sized milling machine or mill-drill machine; drill press, grinder, & hand tools. Estimated Building Time: 3 to 7 years.
The first run of castings for the 3/4" scale H.J. Coventry 0-6-0 switcher, as were produced in late 2007. Additional castings, cast in May 2008 for the FIRST TIME since the 1950s or 60s, are shown in the next photo below.
More 0-6-0 castings, in bronze, produced in May 2008.
The tender frame casting for the D30 class switcher. It has not been available in AT LEAST forty years. Brand new, made in New England USA by the "green sand" method, it is EXACTLY the same as Mr. Coventry used to sell for this locomotive.
Quick Facts.....
Designed by Mr. Coventry to be machined on a 9” South Bend Lathe. Even the cylinders machine in the lathe! (A mill-drill, or lathe milling attachment, can handle the other milled parts). Half-Saddle Piston Valve Cylinders with exhaust ports (and steam and exhaust clearances in the valve bore), “cored in”. These cylinders are EXACTLY the same as the ones Mr. Coventry sold in the 1950s, and are proudly made in New England, USA NO COMPLEX “STEP” BORING in the valve chamber; and no “crazy-shaped” valve liner to machine. The valve bore, and liner, are machined parallel. Clamp the cylinder to a faceplate, bore the parallel borein your 9” (or larger) lathe, and then press in the easily-machined bronze liner. The valve chamber “steam and exhaust” coring in the casting eliminates HOURS of difficult machining, and makes machining easy. The result is an authentic piston-valve engine in 3-1/2” gauge that is straightforward and enjoyable for the hobbyist to machine on small machine tools. No longer will you have to fear piston valves! “Spool piston valve” is standard; semi-slide valve (“drum” valve) optional. Both shown in drawings; both easy to fabricate. Mr. Coventry’s original construction notes, including instructions for EASILY holding the cylinders on a faceplate in the 9” South Bend lathe and machining them; sketches and descriptions of the various jigs and fixtures used; and instructions and sketches on how to construct the boiler and combustion chamber, are included with the castings.
The cylinders, as seen from the top. Fans of "H.J. Coventry" (and astute students of live steam history) will at once recognize from these cylinders' overall shape and style, that these are, without a doubt, H.J. Coventry cylinders. They are, in fact, "The Real McCoy". They look more like HJ Coventry's cylinders than Mr. Coventry's cylinders used to look! They are EXACT duplicates of what Mr. Coventry had on the market in the 1950s. See photo below for a "cutaway" view of the internal coring.
The steam and exhaust cavities and passages are "cored into" the cylinder casting at the foundry. This substantially reduces the complexity of, and time required for, machining.
The internal coring of the iron cylinder (at left) is classic, old-fashioned American pattern and foundry work at its BEST!
Want to Look the Project Over?
Complete set of drawings, copied from Mr. Coventry's originals.....$129.00 plus $25 shipping. Copies of Mr. Coventry's original construction articles from the magazines "The Miniature Locomotive" and "The North American Live Steamer" are available for $29 plus $8 shipping. They detail many aspects of construction including cylinders, drive wheels, boiler, and valve gear.
You may purchase with PAYPAL or your credit card below. You may also pay by check or money order. You may click the link below to see the "side view" (elevation) of the locomotive, as drawn by Mr. Coventry.
Other castings sections will be posted with "payment links" as time allows. If you're interested in purchasing castings that are not yet listed, or the entire set of castings, please inquire.
The brakes! Brake cylinder & head; brake levers; bell cranks; and hangers. Brand new, bronze, and produced in New England USA by the traditional "sand casting" method.....the SAME as Mr. Coventry offered on this locomotive in the 1950s.
Here are the brake cylinders and components after machining, and ready for assembly.
The brake cylinder and its components, machined and assembled, and ready for installation.
The locomotive is equipped with steam-powered brakes controlled from the cab. This rare underside view of the chassis, shows the brake rigging. Three photos and phenomenal machining on the brake section by Jack Bodenmann, California USA.
The 3/4" scale D-30 class USRA 0-6-0 cylinders (with valve crossheads, in bronze, also shown). Half-saddle, piston valve, exhaust ports cored. Steam and exhaust clearances in valve bore also cored, thus eliminating complex "step" boring operations within the bore. Proudly made in New England, USA.
Are the H.J. Coventry cylinders by Friends Yankee Shop Models the finest 3/4" scale piston valve cylinders available anywhere? That's up to you, but those who have already bought them, think so. Top-quality pattern & core work, and highest-grade foundry work, combine to produce the superb casting you see here. These cylinders are made in New England USA by the traditional "sand casting" method and will please you in every regard.
Here is a view of the internal "coring" within the cylinders. The steam and exhaust clearance areas are "stepped" into the valve bore. The exhaust passages that lead from the front & rear ends of the valve bore to the exhaust nozzle are also cored. (the U.S. 25-cent coin, used for size reference, is within one of the exhaust passages). This coring, a modern-day example of "Yesteryear"-type foundrywork, eliminates substantial amounts of complicated boring and drilling work that would otherwise be required to machine piston valve cylinders.
The finished cylinders for the 3/4" scale 0-6-0 USRA switcher. Superb machine and assembly work by Jack Bodenmann, California USA.
The smokebox ring; firedoor ring & hinge; power reverse; tender tank filler; air tank brackets; and some of the various glands.
The draft pipe (also called a Petticoat Pipe); the exhaust pipe and exhaust pipe tip; the smokestack; and the smoke stack washer.
The draft pipe (petticoat) has its "bell shaped" center hole "cored-into" the casting.
The boiler parts: Throat Sheet; smokebox ring; firedoor ring & hinge; and mud ring (tender tank filler also shown). To preserve the authenticity of Mr. Coventry's design, these bronze castings for the boiler were produced. If you prefer an all-copper boiler, you may fabricate these components from such.
The cylinders, front and rear heads, and valve crosshead guides.
A side view of the cylinders and some of the valve gear components. The turrett and the smokebox front are also shown.
Another view of the cylinders and valve gear; this view also shows the frame components including the front deck; the guide yoke and reverse shaft brackets; and the rear (drag) beam. The rear beam has a cored slot for the engine-tender drawbar, thus eliminating the need to create this slot by tedious drilling and filing; or by lots of fabrication time.
Drivers for the 3/4" scale 3-1/2" gauge D30 class USRA switcher.
The sand domes (cast iron; in rear); the steam dome (bronze; left front), and the steam dome cover (bronze; right front).
The smokebox front, and the smokebox door.
The cab; the grates; the rear beam (the drag beam); and the firedoor. Proudly made in New England USA.
