Emma Victoria A 5 inch gauge freelance 0-4-0: Drawn and described by Henry Wood - PART 23

摘要

As mentioned previously, to prevent the extension columns from unscrewing when removing the safety valves, a locking plate is provided. This is made from 1/8 inch thick brass strip, 3/4 inch wide x 13/8 inch long. Start by marking out the centres of the two safety valves (check these from the boiler) and scribe a 3/8 inch radius from each centre as shown. In the centre and on the centre line, drill No. 38 and tap out 1/8 inch x 40 tpi; this is to accept a screwed rod to remove the plate to allow the extensions to be screwed out of the boiler if the need should arise. The next job is to drill and file out the hexagonal holes to line up with the orientation of the columns to a sliding fit.