Restoring a 1-3/4 HP Monarch - Part 2

Reclaiming its crown


| June/July 2010



monarch 1

The Monarch’s broken governor weight.

Photo by Peter Rooke

The following is Part 2 of a three-part series documenting Peter Rooke’s restoration of a 1-3/4 HP Monarch badged by Nelson Bros.  Read Part 1 here .  

Governor weight
One of the governor weights had broken off in transit, splitting not far from the pivot hole. While it was possible to cast one using the unbroken governor weight as a pattern, this was not something that I could do myself. Before considering casting an attempt was made to try and repair the weight.

Both sides of the break were given a good cleaning with a brass brush and were then coated in soldering flux before heating to brazing temperature to draw out all the dirt. Despite being a recent and clean break it was amazing the amount of dirt that came out of the casting, which turned the flux black.

When the pieces had cooled, the flux and dirt were wire brushed off, also using a sharp pointed cutter in the Dremel to clean out the crevices. Again, both pieces were coated in flux and the process repeated until the flux retained a degree of its original color on heating. Then it was time to braze the two pieces together.

After cleaning and fluxing the two pieces, they were wedged in the correct position on the brazing hearth. In order to avoid overheating the thinner section and destroying the properties of the flux, heat was first applied to the section by the body of the weight then, when at brazing temperature, the flame was moved up to the other parts of the repair. Once the braze had flowed and the repair made, the weight was covered with fire bricks and allowed to cool slowly to stop the iron from becoming brittle.

To support and strengthen the repair, a hole was drilled lengthways through the area of the break so that a 0.125-inch steel rod could be inserted. The area around the rod was cleaned and the rod covered in flux before it was pushed into the hole. The weight was supported then heated once more, and braze touched to the rod so the rod was firmly soldered along its length. Again, it was allowed to cool under the warm fire bricks.