< Complete the Boiler >
Finished backhead and smokebox tubeplate.
Lining up of front and back regulator bushes in the lathe.
A careless annealing operation resulted in melt of the top tube! The tube was removed for replacement.
A little modification of the boiler.
1) Adding a bush for waterfeed.
2) Changing the position of check valve from backhead to both sides of barrel front.
Again the tubeplate was protected before soldering. Generally smokebox tubeplate is soldered to barrel with tubes in later stage. But I prefer soldering only the tubeplate here.
The foundation ring was modified to eliminate the opens - the red area in the section
Machined foundation ring. Note the half-round recess in both sides to clear the blowdown bushes.
Watergauge bush is partly machined from a gunmetal casting.
I made sixty counterhead screws for "stay" from 4mm phosphoric bronze wire. The screw wasn't slotted only at the top of the head but also at the side of thread to form a channel for silver solder.
The boiler was fixed onto the table to drill and tap for stays. The length of the clamping screws were calculated in CAD to ensure accurate angle.
Tools for the stays. From left, small drill to catch the punch mark, drill for hole before tapping, countersink against the counterhead stay, "Drill tap" as alteration of "Lead tap" to thread both outer and inner wrappers, die for threading stays.
A long arbor is necessary to drill the throat plate because the holes are very closed to the barrel.
The stays are home and ready for soldering. Note the tubes are packed with asbestos yarn to prevent overheat. This kind of asbestos is still available in Japan, however I don't recommend it for its harmfulness. Graphite yarn is a good substitute.
Jigs for soldering. From left, syringe to drop flux, scratch rod to adjust the position of the solder, cramping tool to hold the "U" shape solder.
Procedure is as follows.1) The stay with flux is screwed home and brass nut with flux is screwed from inside. 2) Flux is dropped at the foot of the stay between inner and outer wrappers by the syringe. 3) The "U" shape solder is hooked onto the foot. 4) Solder ring is put on the head of the stay. 5) Heat up whole job with propane blowpipe to melt both inner and outer solder.
So as to solder the backhead and the foundation ring at a time, I changed setup from the left to the right in 20 seconds.
Final soldering operation is for the front of the tubes. The tool is "Drift" to extend the front end of the tubes to fit to the hole.
The Battle of Boiler exactly started here. I spent one month to settle leakage of the boiler. After plenty of sleepless night, I decided I will never build a boiler again! But the decision was forgotten in three month....
Silver soldering operation in a Livesteam society: They made great help to fix the leakage of my boiler.
Hydraulic pressure test and the plugs for it.
Boilermaking with Tears?