A Window Water Gauge
The Live Steamer, July-August 1950
Here is a water gauge that is simple to make and has given satisfactory service and reliable readings on a 3-1/2 inch gauge engine.
The main part is the body, which has 1/4 inch end milled slot 1/8 inch deep thru the middle and each end of the slot has a spigot. The bottom one can be a 1/8 pipe thread into a boiler bushing about 1/8 inch above the crown sheet. This pipe thread spigot on the gauge, should be long enough to screw the gage on tight and still have clearance for the union on the upper end.
The steam pipe to the upper spigot should be as short as possible. If your boiler is large and there is not enough clearance for the union, the union spigot can be offset to the outside of the body by a piece of 1/4 inch square brass with 5/32 inch diameter holes to connect to water passage in the gauge.
The glass is of Pyrex and unless you are adept at cutting glass, its best to get some strips already cut to 7/16 inch width. It is easy enough to cut the length with an ordinary glass cutter. Be sure there are no cracks in the glass. The neoprene rubber is a gasket with center cut out to match the body, and outside to match the glass. The cardboard is sized likewise. The holes in the body are spotted from holes in the retainer to insure alignment.
The gauge should be put on the boiler, then glass, gaskets and retainer screwed on, be careful in tightening the #2-56 screws.
The important thing is to have all 12 screws tightened evenly and not too hard. It is surprising how little pressure is required on all screws to make this gauge glass hold 150 pounds pressure. The size of this gauge can be varied, but it will be well to keep the screw spacing at 5/16 inch. If there is not sufficient room on your boiler backhead to screw gauge on tight, the 1/8 pipe spigot can be a union connection as shown in the alternate arrangement.
