John Smyth 4-1/2 hp Restoration – Part 2 of 5

Peter Rooke makes a replica muffler and cart for his 1914 John Smyth engine.

| April/May 2016

  • 1914 John Smyth
    Photo by Peter Rooke
  • Laying strips of steel over a wooden form to make the first half of the muffler.
    Photo by Peter Rooke
  • Tack welding the second layer of steel for the muffler. The strips overlap the seams of the first layer.
    Photo by Peter Rooke
  • The first muffler half, lugs fitted and ready for threaded boss.
    Photo by Peter Rooke
  • The completed muffler bolted together with the threaded boss welded in and a pipe nipple fitted.
    Photo by Peter Rooke
  • Drilling holes through a section of pipe before sliding it over the axle hubs.
    Photo by Peter Rooke
  • Completed hubs in the background with components for making the spokes.
    Photo by Peter Rooke
  • The jig for aligning a spoke and a spoke end, with a tack-welded spoke end visible to the left.
    Photo by Peter Rooke
  • The completed spokes, ready for fitting to the hubs and rims.
    Photo by Peter Rooke
  • Steel for the wheel rims, the position of the spokes marked and predrilled 0.125-inch.
    Photo by Peter Rooke
  • The setup for bending the wheel rims, using a scrap piece of cast iron to define the radius.
    Photo by Peter Rooke
  • Coming together: Tack welding the spokes to the hub.
    Photo by Peter Rooke
  • Using clamps to hold the rim in place while welding.
    Photo by Peter Rooke
  • A spoke set in a rim, the spoke and rim prepared for welding.
    Photo by Peter Rooke
  • A completed wheel with the spoke ends ground smooth.
    Photo by Peter Rooke
  • Setting up to weld the 1-inch axle shafts on the fixed front axle assembly for the cart.
    Photo by Peter Rooke
  • Plates used to fabricate the front axle support bracket.
    Photo by Peter Rooke
  • The front axle support bracket after welding plates and end pieces together.
    Photo by Peter Rooke
  • The rear pivoting axle starts taking shape with its bearing plate added.
    Photo by Peter Rooke
  • Starting the process of making the rear pivoting axle support.
    Photo by Peter Rooke
  • The rear pivoting axle support bracket roughed out.
    Photo by Peter Rooke
  • Adding the handle supports to the rear pivoting axle.
    Photo by Peter Rooke
  • The completed rear pivoting axle.
    Photo by Peter Rooke
  • The completed cart, new handle fixed to the rear pivoting axle.
    Photo by Peter Rooke
  • The initial brazed repair.
    Photo by Peter Rooke
  • The repair of the second crack, with bronze screws at ends.
    Photo by Peter Rooke
  • Heads roughly fitted to new valve stems before final finishing.
    Photo by Peter Rooke
  • Head trimmed to size and 45-degree angle being cut.
    Photo by Peter Rooke
  • The finished cylinder head with new valves seated and fitted and new head gasket cut and fitted.
    Photo by Peter Rooke

Muffler

There appear to be many different muffler styles for this engine; a plain ball muffler, a ball muffler with a ridge around the gap and a “tin hat” style. Most photographs examined showed a ball muffler for this size of engine and a comment noted during the research said that the plain muffler was used on the early engines to around 1915.

The diameter for a 4-1/2 hp engine was 7 inches, but mufflers this size are nonexistent in the U.K. Indeed, there was already a 5-inch ball muffler sitting in our son’s garage in Houston, Texas, waiting for someone with spare weight allowance to bring over to the U.K.!

Thoughts then turned to making a replica muffler, the difficulty being to make the walls thick enough so it would sound like an original. With no press equipment there was no way to form a steel muffler with a 0.25-inch wall thickness, so rather than make patterns for casting I decided to fabricate one.

The first step was to make a wooden pattern for one-half of the muffler, so several bits of hardwood were glued together, ready to be turned and shaped on the lathe. This would be 6.5 inches maximum diameter to fit inside the 0.25-inch thick walls.



The radius tool for the lathe could not be set for a 6.5-inch diameter. A series of calculations were made to generate the diameter of the dome at 0.125-inch intervals so the adjustment dials could be used on the lathe to create a rough dome. This was then sanded to give a fairly smooth finish. A pattern was cut from cards to get the shape for 10 pieces to create the dome before cutting these out of strips of 0.125-inch thick steel.

These segments were then bent to shape to fit the dome, first bent on the long axis around a small pulley, and then the short axis first using the vise and then finishing off with an engineer’s ball peen hammer. Once all 10 segments were shaped, the wooden pattern was soaked in water before resting the strips on it and tack welding them all in position.