Stuart Boiler Feed Pump

[K.B.C]

Florin,

I am really intrigued as to how you spot the casting to take the Cap head socket screws, it's one of those things that I have never had explained or shown, so perhaps you would explain.

George.

[Florian Eberhard]

Hi George

You are talking about how to countersink the screw, right?
(By the way - the cap screw is only temorary - I will of course use washers, nuts and studs in the end.)

Be right back with a picture


Here I am:
I have made a "reverse countersink" d-bit. Its ground free hand so you see its not looking so nice 
However, the trick of it is to use the bore as a guide for countersinking. For this, I have turned the shaft near the "head" of the tool to the drilled hole size (Thats the shiny part).

How I used it:
I have taken the d-bit into the collet chuck of the milling machine and then moved the tool up slowly. I had to lower the table for this. It is imortant not to use the quill if you do not have a fine-feed for it (often realized with a worm gear reduction drive) because the surface is not straight. This could get dangerous for the tool and for the cast part aswell! (And maybe also for yourself if you do not watch out!!!)
The last picture is only for demonstration.

Florian
ps: I wanted to write about how I did this but it looks like I forgot about. Good you did remind me on it!

[NickG]

Brilliant stuff Florian.

[steamer]

Nice one Florian!

Dave

[K.B.C]

Hi Florian,
Thanks for taking the time to show your method of counter boring on the Casting.
I have always thought that it would have to be done from behind but couldn't think of a way to do it, "D" bits are no problem to make I think that I have one for every size that I have ever needed.

It's a pity that you hadn't posted this earlier as yesterday I lashed up a method and as you know the problem is getting past the water end part of the casting to get a straight line to mill the spots.

 I used a tool like an end mill with very rough teeth on the dia 3/8" , I don't know what you would call it, I fixed the shank into a piece of Mild steel and machined the mild steel rod as small as possible in order to get past the water end casting.
This allowed me to fix it into the collet chuck on the mill , tilt the casting by using a piece o 1/16" thk packing which allowed me to get down to the casting.

It did the job but not very pretty but as it will eventually be painted it may not be so noticeable.

No 1.

The modified tool.

No 2.

Spot face on pump casting.

No 3

Piston fitted with Silicone "O" ring.

No 4
Progress of pump to date, the 5/32" rod is only there to mark off the center for the end stop/adjusting screw.


I have an old casting which I made a mess of but it will be good enough to make a tool as you described and see how I get on.

George.

[swilliams]

Nice job on the upside down spot facing Florian. Always nice to see a home made tool getting the job done.

Steve

[Florian Eberhard]

Again "soon" turned out to be more than one day... 


The tappet followed being machined. First, I drilled and reamed the hole for the shaft. That was followed by milling the sides and the lower radius with the rotary table. The tapped was held with a simple mandrel. The tapped has a 6mm bore and goes on a stub on the top of the mandrel. That fit is quite tight (But you can still put them together by hand) and then secured by a M4 screw. 
Then I had to drill the cross hole for the clamp (Is that called like that?)
Afterwards, I machined the clamp from a piece of 4mm rod.
Done - the clamp is finished and the tapped also (almost at least - still needs some filing but thats gonna come later)
Also, I had to make the "set collars". I never liked the look of them and so I decided to do it slightly different here aswell. I decided to make two clamp collars.
Cut off and chamfered. The screw in front of them is a M1.2 screw.
Milling steps, center-drilling (The final hole was drilled on the drill press as I have no good drill chuck for the machine - need to get me one...) and finally slitting the collars.

So much for now. Till next time (whenever that will be  )

[Florian Eberhard]

Not thats is the point where all the parts are ready to try let the pump running.

I have a so called "lapping film" (It is actually abrasive paper which is water- and oil resistant and has a very precise thickness) which I used to get the surfaces plain and nice:
There are different grain sizes and with the smallest one, the surfaces can be polished mirror-like (look at the d-valve!)
I assembled all the parts and tried. The pump did not move for a single stroke. 
Disassembled all the things, checked everything and considered again my thoughts about the principle. I had everything right but why didnt the pump move!?

The first thing I have seen was that the surface on the shuttle piston bore was not as good as it should be and the piston was running rough.
I then took a 5mm lapping mandrel (which I had from another project) and tried to improve the surface so the O-ring wouldn't stick on it.

Reassembled and the pump moved for a few strokes but then again stopped doing anything.
I disassembled again and found that the O-ring groove on the piston was not deep enought, the shuttle piston was still not moving as free as it should be. (somehow I didn't notice that before)

However, I made the grooves deeper and tried again.

AND THE PUMP IS DOING WHAT IT SHOULD: 

<a href="https://www.youtube.com/watch?v=5OxhSaGZZRk" target="_blank">http://www.youtube.com/watch?v=5OxhSaGZZRk</a>

[Florian Eberhard]

Now that is of course only actuated by hand and therefore the next step was to let it run by itself:

Still, I was having problems because the pump stopped when reducing the pressure and then I was not able to start it again by itself.
I first was really helpless and then had the Idea that the shuttle piston might be too small.
I then made another shuttle piston  (that is the 4th one  ) now with 6 mm diameter.
The bore in the valve chest was extended using a new 6mm endmill:
The bore turned out to be very smooth. Here you can see why I had to use an endmill:
And finally the new shuttle valve piston beneath the old one.

And the pump is running!
<a href="https://www.youtube.com/watch?v=BuEWxvJh79Y" target="_blank">http://www.youtube.com/watch?v=BuEWxvJh79Y</a>


BUT: There is still the Problem that the pump "gets stuck" - I was really going to be pissed off and couldn't think of any reason at that moment.   

That's it for today - the solution to this problem (there was a solution) will come soon 

[Dave Otto]

Nice Job Florian!

I'm sure that you will get it sorted out and running just the way you want.

Dave

[swilliams]

Looking good Florian. You'll get it sorted

Steve

[K.B.C]

Florian,
Do you have any lubrication on your air line to the pump ?
If not it could be the "O" rings drying out and stopping the pump.

Southworth make  steam boiler pumps in WEIR vertical style with slide valves and shuttle vales but no "O" rings on the shuttle so could you try the pump without the "O" rings.

I have made the WEIR type by Southworth, the 6" high vertical one and the latest one that I have made is the small 3" vertical WEIR type pump.

Both are self starting at very low speeds and the only "O" rings that I use are SILICONE on the pistons.

Just a thought.

George.
 

[Roger B]

Congratulations  It always feels good when something you have made works.

[Florian Eberhard]

Thanks Guys

I already have sorted out that problem - I just didn't write here what the solution to it was 

Florian

[NickG]

Brilliant Florian, seems to work really well that, have you tried it pumping anything yet?