2 videos of the triple and the vertical boiler and the Southworth boiler feed pump working together for the first time. Not perfectly yet, but working.
A couple of days in the workshop, and the large castings are almost fully machined. Straightforward machining. Made a couple of mistakes, but none fatal. Changing BA fasteners to metric.
The steam cylinders block in the mill vise. Almost complete water cylinders block sitting behind for the photo.
Steam cylinders on right, water cylinders on left. The temporary steel pins are to ensure accurate alignment of the 2 blocks. Water and steam passages come later.
This is the first model machining which I have done since April. It should be second nature, but I admit to a bit of hesitation, nervousness, initially. Especially starting on an irregular, slightly complicated shape like these. But it is all coming back now. And I am really enjoying it.
My CNC mill is now mostly functioning, although several functions are yet to be connected. The main spindle and XY&Z axes are working, and responding appropriately to Mach3 commands from the laptop computer. It has taken longer than anticipated so far, mainly due to difficulty in understanding manuals supplied from Asia. Axis limit and homing switches, oil pump, coolant pump, work light, and cooling fans still to be connected.
So there has been little of general interest coming out of my workshop. Hence no posts on this site. Not that I have been idle.
I disassembled the top slide on the Colchester lathe to discover the cause for excessive back-lash. It was a worn acme thread bronze nut. No luck yet in finding a new nut for this 45 year old lathe. I will have to make one. Meanwhile, I used a quick and dirty trick to reduce the back-lash which I will detail soon.
The top-slide acme screw and bronze nut which needs replacing.
I also cleaned and freed up a 3 jaw 10″ chuck which I bought on Ebay. It was frozen solid, so I soaked it in kerosene bath for a few months. Actually, I forgot all about it while it was in the kerosene, and accidentally rediscovered it. This time, after using an impact screwdriver, I was able to open it up and expose the gears and get them moving. Might be worth a photo also.
The 240mm diameter chuck. I was tempted to buy by the removable, reversible jaws. Thinking that I could make some soft jaws. Trouble is that it is an industrial production line chuck with very little movement. But it is nice and tight. Still deciding. At least I can wind the jaws in and out a bit now.
And I finally got around to installing piston rings in the triple expansion steam engine. Used Viton O-rings. Not a difficult task, and it should not be difficult to replace them from time to time in future. Will be interesting to see if the engine performance improves.
Now to get onto my next project. I have plans and bronze castings for a Southworth design water pump, for replenishing the vertical boiler water while it is in use. It was a surprise to me, just how much water is consumed by a boiler which is powering a model steam engine. To date I have used a hand pump, but having seen a steam powered pump in action, I have decided to make one.
The steam is supplied from the boiler which is being replenished. The pump has to use steam at boiler steam pressure, to force water into the boiler. So the pump has to raise the pressure of the feed water above the pressure of the steam which is powering the pump. The clever pump design uses large steam driven pistons to drive smaller water pump pistons.
Larger steam pistons top right 5/8″ dia, water pistons bottom left 3/8″ dia.
Here is a video of a Southworth pump in action. It was made by Stuart Tankard. Here it is running on compressed air, but I have seen it working similarly on steam. I will be making one of the same design, hopefully approaching this level of finish.
A build of larger version of the pump was described by J. Bertinat in a series of articles “Model Engineer” in 1993 (first article 18 June 1993).
The unmachined castings. Lumps of rough bronze. And the plans.
One of the castings after preliminary machining to establish some faces. The “water cylinders” block. Part no. 6
Good quality castings.
johnsmachines 