FINISHED ENGINE AND BOILER FEED PUMP.
As I said that I wasn't pleased with the pump that I had made as it appeared too tall and had too many parts so I have made this othedr to a more simpler design.
All the pumps that I make are more or less derived from K.N.Harris's book on boiler building but I now use Nitrile hard rubber balls.
The Nitrile unlike Steel balls require a coned landing as against the sharp edges of the steel ball.
I make the landings using a 3/16" cemtre drill by going down until I feel the tool touch the metal, start up the lathe and counter bore for for .025" and leave the lathe spinning to give the surface a slight polish.
I make all pump barrel and the valve box and after boring to suit 3/16" balls I tap about 6 threads with a first taper 1/4 x 32 tap on both ends of the valve box, this gives a good start after soldering as the intense heat can burn a full thread, after all of the silver soldering has been done go back in and tap a full thread in the metal.
No 1.
The ram barrel and valve box ready to solder.
No 2
After soldering and ready to put in the pickle jar
While soldering on the mounting bracket take a piece of 1/4" dia bar and coat it wil the smoke from a candel or any other thing that gives heavy smoke when burning.
Put the 1/4" bar into the reamed ram hole and clamp on the bracket, if you don't do this the hole when hot enough to solder will turn oval whith the slightest of pressure.
Putting the bar inside while soldering prevents this and the smoked rod will come back out whout sticking.
No3.
All the components of the pump ready to assemble.
No 4
Pump assembled and bolted to the engine base plate.
Stuart recommends that their pump is mounted on the 2- holes at the base of the main casting, this I don't like as I have experienced the pump under working conditions to move and if not noticed can be a bit of a disaster, hence the longer bolts into the side of the base plate.
No5 & 6.
Pump bolted in position with a 1/4 x 32 Connection at the delivery end to take 5/32" dia copper pipe and a push on connector on the suction side to take the Silicone tube the the Aero guys use for fuel.
The only thing that I have not shown is the 10 b.a. round head screw in position to hold in the rear bearing of the pump, the tapped hole can just be seen in the side of the barrel, the hole abovr is a small counter sunk oil hole.
So there we have it , engine completed and I must say it's one of the best runners that I have made, I put this down to a mod that I made to my Chinees lathe, some time ago I bought a British made " Pratt-Burnered " chuck and I made the back plate that the regester of the chuck fits too a slack fit, about .005 " undersize.
This allows me to adjust the chuck with a D.T.I. to run true on a dedicated jaw, in my case No 2 jaw, the chuck has a 3- bolt Hex head bolt fixing from the front and if ever I have a tool dig in I can very simoly re-adjust the chuck, simple but effective and worth the trouble.
Next job isn't one of my favourites, stripping down for painting so I only hope that it goes together and runs as well so I shall post my last pics when painted.
I do hope that somebody will read this thread and have a go at at D10.
George.