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[ooyah/2]

Having built several steam pumps and as I am now starting on another I thought that I would describe the machining process in case anybody fancied building one.
Her is a pic of a previous one and hopefully the one described will turn out the same.


The first thing that I start with is the main body casting, I fettle it by filing off all the molding flashes and then I clean up the base.
This is done by rubbing the casting on a large flat file until the base is clean,
Mark of the center line as per the DRG and center pop the cross lines.
Set the casting up in the 4- jaw with suitable packing and get the center pop to run true, a jig is made to fit over the eventual valve stop and all is trued up so that the center pop runs true, the base of the casting must be square to the center line of the lathe.


With center drill, drill the casting and then run a 1/2" dia drill straight thro' the casting and finish off by boring out to 9/16" bore.
You can if you wish ream the hole if you don't want to bore it.

After boring thro" you can then machine the end of the casting that supports the cylinder.
It's one of the most critical machining operation, if the end of the casting isn't  square with the bored holes it will be very difficult when assembling to get the pump to run.







FINISHED CASTING.


END COVERS FOR CYLINDER.

Again it's important to file of all the casting flashes, catch the casting on the end that has to be eventually drilled and tapped in the 3- jaw, this allows you to machine down the thickness of the plate and leave enough metal on the register to turn it around and then machine the plate , drill and tap, turn down the boss for packing gland.
Turn the plate around and grip in 3- jaw you can then face off the plate and turn the register to fit the cylinder bore and reduce the end to 1/32" thk.







The next procedure is machining the cylinder and the end cover.

MACHINING CYLINDER.

This is a straight forward 4-jaw with packing procedure.


The cylinder casting requires that the molding flash is ether filed off or milled to give a reasonable flat finish.
The center lines can be marked on remembering that the face that goes to the end plate has to be true to the bore. this is identified by the drain valve bosses.


Once set up square the casting is bored thro" to size and faced this ensures that the bore is square to this end, the casting can then be turned around and the end faced to size, this ends squareness isn't so important as the other end.

The cylinder is set up in the mill to mill the top face to size, if a mill isn't available it can be filed.


The only other job is to machine the cylinder end which is as the other one already described.

TO BE CONTINUED.
George

[ooyah/2]

MAIN FRAME AND CYLINDER

The steam chest can ether be filed or milled to bring to size and to square it.

SETTING UP STEAM CHEST IN 4 -jaw,
The steam chest has to have the auxiliary valve hole drilled and reamed 5/32 " dia and the spigot for the packing gland tapped 1/4 x 32 tpi
Set it up in 4-jaw with packing to protect the machined surfaces and center the hole for drilling.


Next the steam chest is set up to drill and ream 1/4" dia hole for the shuttle valve.



STEAM CHEST AND CYLINDER ARE NOW READY TO BE MARKED OFF AND DRILLED FOR THE STEAM PASSAGES.
This has to be one of the most difficult jobs in the whole model.
The draughtsman who drew this up should have had is butt kicked.
There is no DATUM line to work from so I have found that the best way is to scribe center lines on the steam chest and cylinder face and then with note pad work out the dimensions and split them over the center lines.
A small set of draughtsmans dividers are best and to use the old dictum MARK TWICE DRILL ONCE .
Take care when drilling the cast gunmetal steam chest and cylinder that you don't break drills as you are breaking into cross galleries.

STEAM CHEST AND CYLINDER WITH STEAM PASSAGES DRILLED.


The next process is to mark off, drill, tap and bolt the end covers and the steam chest to the cylinder.

[kno3]

Thanks for taking the time to explain all steps. I have a question about the principle of operation:
I have noticed that these pumps have a valve and beside it another small piston which seems to move free. Could you please explain what its role is?
Would it also be possible to use a standard cylinder, with a slide valve or piston valve, to drive a pump in the same fashion as this one?

[ooyah/2]

The pump works by virtue of the Auxiliary valve having a port always open to steam which lets the steam into one end of the shuttle piston.
This moves and opens a port to the piston which drives the pump ram and moves the auxiliary valve via the 2- collars and the fork fitted to the pump ram which switches the steam to the other  end of the shuttle which reverses the steam to the other  end of the piston and then the cycle is repeated.
These pumps are self starting and can be controlled for speed and stroke.
Speed by reducing the steam input and stroke by bringing the 2- collars together.

No you can't use a standard cylinder with a slide valve.to make a pump like this.

GENERAL ARRANGEMENT OF PUMP.

COMPONENTS OF THE STEAM PUMP.
The auxiliary valve is the long 5/32" dia rod and the shuttle is the small 1/4" dia rod.

[oldiron]

  Interesting write up, thanks for taking the time. I've built two of these and still haven't been successful in getting them to run on steam. They run on air but not on steam.  They'll only get power in one direction even after fiddling with the adjustment. Thought it was condensate in the shuttle or lengthening of the shuttle due to heat. Made replacement shuttles but still no go.

John

[ooyah/2]

Hi John,
Sorry to hear that you can't get your pumps to work on steam
I have made several pumps, this is No 7 and all have worked on steam.
Here are some of the problems that I have encountered.

1--If when the pump is cold and dry if you can't move the pump rod by hand freely back and forth something is out of line and believe me it doesn't take much.
2-- Try lengthening the stroke of the 5/32" auxiliary shuttle by screwing back the 5 BA stop screw, you may have to machine a little off the valve end to get a longer stroke.
3-- There must be no steam leaks on any of the faces and joints, when run on air these are not visible but the slightest steam leaks causes problems.
4-- I make the pistons from gun metal making them oversize and machining to size when screwed on to the pump ram and fit Silicone "O" rings

If you have met all these conditions and I assume that you have checked all the valve dimensions the pump should start on steam without the drain valves open.
The dimensioning of the steam chest leaves a lot to be desired and difficult to follow.
I hope that this has been of some help and would like to hear how you get on.

George.

[oldiron]

George:

  Thanks for the help. I'll go over mine again with your advice.

John

[ooyah/2]

Now with the steam chest cylinder and covers this assembly can now be put together bolted up.



With the 5/32" dia auxiliary valve and 1/4" dia pump ram fitted it can be made up into an assembly and fitted to the main casting.


I then started on the water pump castings.

I made up a mandrill with both ends screwed, 1- end 5/16 x 26 tpi and the other end 7/16 x 26 tpi.
this allows me to mount the casting for machining.



First set the casting up in the 3- jaw and machine the face, drill and tap as drawing and tap 5/16 x 26 tpi, mount this on the mandrill  which allows the end that fits into the main frame to be machined.
turn down the end as per drawing to fit main frame.
drillthro" and ream 1/4" dia for pump ram.
Drill and tap 7/16 x 26 tpi for packing gland.






With the bottom half of the water pump casting  machined it can be tried out by fitting to main casting.
 



Next part will be to drill and tap the bottom half to take ball valves and thread the end for the suction pipe, before starting on the top half which is the delivery end.
George.

[ooyah/2]

Continuing with the water pump casting if you take it out of the 4- jaw and mount it on the 3/8 x 26 threaded mandrill the packing gland can be machined and tapped  7/17" x 26 tpi to take the packing gland.

Next job is to remount the casting in the 4- jaw and center the flange for machining





This can now be faced and drilled for 1/4" St/St ball.
The bottom thread on the suction valve box needs to be threaded 7/16 x 26 to take the water connection.
As this is very off set a mandrill was made to mount the casting and then center it for boring, I have a small face plate that has a 1.5" dia stub which when mounted in the 4- jaw enables you to center the casting




You can then get on to the delivery casting which most of it can be machined in the 3- jaw. grip the casting on the large boss and machine the end for the end cap, face it and bore it out as the Drawing and tap the end 7/16" x 26
Turn it around and mount it on the mandrill and machine the end to fit into the suction pump casting leaving 3'32" clearance for the ball. then you can machine the





The retaining slots can now be filed or milled





The fixing holes can now be drilled and tapped




Last job on the water pump castings is to drill the gallery thro' into the pump chamber.



All the water pump castings can now be bolted into an assembly, which now leaves all the little bits and pieces to be made.


George

[oldiron]

Great build thread. Thanks for taking the time.

John

[ooyah/2]

Hi John,
Have you had any luck in getting your pump to work on steam?
George.

[oldiron]

Hi John,
Have you had any luck in getting your pump to work on steam?
George.

 I haven't had a chance to get back at it yet. Some other projects on the bench at the moment.

John

[ooyah/2]

Continuing with the pump build the next job was making the gland nuts, this is a straight turning, threading 7/16" x 26 tpi, boring 1/4" dia thro" and marking off the positions for the slots in the gland O/Side dia.




The drawing calls for 6- equi spaced slots around the outside edge of the gland nut for tightening up, I don't like this arrangement as a special spanner is required.
I drill 6- 5/64" dia holes on the outside which lets me use a 1/16" dia rod to bar them round and tighten them.
I mount them in a collet made from a piece of hex bar and if the holes are centralized to the flats it's only a matter of turning the hex over for drilling the holes.



I have made an indexing tool with a hardened steel point mounted at machine center line, a tube drilled and tapped with a bolt and lock nut set at the machine center line minus half the thickness of the chuck jaw, I can then scribe the lines required to give 6 nearly equal spaces.







This tool can also be used for marking of the hole spacing in cylinder covers.

The last little job today was marking of , filing.drilling and fitting the arm that operates the auxiliary valve.





After filing the end that fits over the 5/32" auxiliary shuttle it can all be made up into an assembly.

Locking arrangement to lock the arm to the 1/4" pump ram is next with the rest of the fittings to be made.

NEARLY THERE.
George.

[ooyah/2]

The pump ram was next to be made, Stuart supplies a Piece of 5/8" dia St/St bar and you are supposed to machine the ram down to 1/4" dia and then the pump piston to 1/2" dia all in the one piece and to pack with lamp cotton ( lets you see how old the drawing is ).
I have never liked this and in all the pumps that I have made I make the piston separate from the rod.
I take a piece of 1/4" dia St/St rod and screw the end 4 BA x 9/16" long, make the piston from Phos/Bronze machine it to.050" oversize and drill and tap 4BA, screw and fix it on to the pump ram.
You can then machine it to size in the 3-jaw and at the same time machine the groove for the silicone "O" ring, don't leave sharp edges on the groove take a light  rub with a smooth file just to take the edge of as it can cut the silicone 'O'  ring when putting it on.

Next is the auxiliary valve which is made from a piece of 5/32" dia St/St rod, machine the ports as per the drawing but proceed carefully as again the dimensions are all over the place.
I start by machining the ports with a flat faced parting tool mounted on the back tool post and proceed a little at a time moving the job out bit by bit as it's a big overhang if you don't watch you can bend the rod.

Next is the Shuttle valve, a very straight forward and easy job made from 1/4" dia St/St, make sure that the edges are very sharp as it makes a great difference to the pumps performance.
2- collars are made, as is the Auxiliary valve operating arm.

COMPLETED PARTS BEFORE ASSEMBLY.


NEEDLE VALVES
 I make my own needle drain valves as the cock valves made by STUART and others are like full size cock valves, they need constant care and they still leak.
I wish that I had a £1 for every time I had to strip and lap the taper of the cock valves with Pumic powder and black graphite.






After assembling everything I put it onto the air line and with 30Psi it started first kick, It's always a thrill when you make a working model and the time that you have put into it, it works,  it makes it all worth while.

Everything now has to be stripped down for painting and gaskets made to fit it all together again and check out the pumps working ability on steam as I don't consider it a steam pump unless it works on steam.

PAINTED CASTING AND WATER PUMP.







I still have to make the Displacement Lubricator , the one show at the start is from another pump.

[ooyah/2]

After assembling the pump for a trial on air which was a great success it all had to be stripped down to make and fit all the gaskets required to make it steam tight,Once the gaskets have been made with the material supplied the next step is to make the Displacement lubricator and a Tee piece to affix to the steam inlet of the pump.
To make the main body of the lubricator I use a piece of1/2" dia brass .  Cut off 1.25" of the material and chuck up in the 3- jaw, machinre the end down to 5/16" dia x 1/4" long, drill 5/64" x 1/2" into the bar , then drill down 1/4" deep x 5/32" to tap 3/16 x 32 tpi this is for the drain valve.
Turn the job around and drill down 3/8" x 1" deep to meet thye 5/64" hole already drilled up from the bottom and tap the end 7/16 x 26  tpi for the cap.  With a fine boring tool machine the inside of the bar to 7/16" dia inside , this thins down the wall and allows the steam to condensate quicker in the thinner wall of the Lubricator.
A cross hole 1/4" dia is drilled 5/16" down from the top of the lubricator to take the needle valve assembly which will be S/Soldered in.

The needle valve and it's holder is a straight forward turning job with the needle valve end threaded 5/32 x 40 and machined to a 30deg included angle.
The drain valve again a turning job with a 5/32" dia hole drilled down the middle but stopping short to take a hole drilled at 90deg to let out the water condensate.



These are all the parts required for the lubricator that have been cleaned in Citric acid and polished and are now all assembled ready to be screwed into the steam chest.



A Tee piece is required to fix the lubricator to the steam inlet, again a straight turning job of a piece of 1/4" dia bar 1" long drilled thro" 5/64" and then screw 1- end 3/16 x 40 to screw into the steam chest and the other end 1/4 x 32 to take steam pipe from the boiler.
Chuck up a piece of 5/16" x 3/4" long bar and drill and tap one end 1/4 x 32, this is to take the lubricator,  These 2- parts are now S/Soldered to form the Tee and all holes are drilled thro' clear.











Unfortunately at present I don't have a test boiler, will need to make one next ,so I have to link the pump up to the boiler in my steam tug with a long connection.
I am pleased to say that the pump is completely steam tight on all the joints and operates at a pressure down to 10 psi, as it isn't pumping against boiler pressure the steam rushes thro' and not being allowed to work , however this will be dramatically improved when actually pumping against boiler pressure.

So there we are I hope that this has been  a help to any body contemplating building one.
It's not the easiest of the STUART models to machine but if one takes care and time to study the dimensions it turns out as a fine model and  when it  is fired up and goes it makes it all worth while.

THE END.

George.

[Circlip]

Slukin good George 

  Regards   Ian.

[ooyah/2]

OOPS Ian, posted the wrong pics, here are the finished ones with Lubricator fitted.
Must say that of all the pumps that I have made it's the only one that worked first time on air and first time on steam without any leaks.
It's really a nice mover.

Here are the final ones with the Displacement Lubricator fitted.








THINK IT'S THE END THIS TIME.

George.

[Patternmaker]

Superb engineering George.

Mick

[ooyah/2]

Thank's Mick,
Just trying to emulate the very high standard that you have set with the launch build.
George.