Eine Dampfpumpe or a steam pump

[Michael S.]

The partition wall to the valve chamber can be quite thin.

It's important that the ball isn't sucked in. Or you should check how far the piston swings to the right.

Michael

[Sanjay F]

From the drawing below I think the piston rod is in the bottom right and is 36mm and the piston itself is top right and is 7mm. Overall length 43mm, so I'm thinking if I make the shaft 45mm instead of 46mm then reduce the piston rod by 1mm to 35mm?

Will that work?

[Jasonb]

I would have thought the piston rod needs to be longer.

Long enough so the piston goe salmost all that way to the bottom say 45mm

Enough for the gland length

something between gland and cross head

Enough for the crosshead thickness

And a bit sticking out the end


I would also have expected the piston rod to be 3mm at the end as that is the size of the piston. Is it longer than 7mm and with a thread for a nut? Or is it a double acting pump so the piston fits the middle of the piston rod? which again points to a 3mm rod.

[Sanjay F]

Yes, of course, how silly of me!

It must be the rod on the right (see below); I'm still going to stick with 45mm shaft depth to give myself some wiggle room, I think I can adjust the piston rod accordingly

[Jasonb]

Thats better, looks like the plain end solders to the piston though for a display trickle Loctite would do.

[Sanjay F]

Just finished a nervy morning/afternoon drilling in increments upto 10mm and finished of with a 10mm end mill to flatten the bottom to 45mm depth - it took a while but was definitely work making both jigs to hold the piece and I think the 'stoning' of the drill bits helped. I'll now need to get myself and Imperial set of drill bits to 'stone'!

[Sanjay F]

All major holes have now been drilled and/or tapped in the pump body, just a few small ones left for flanges etc. which I'll spot through once I've made them.

Just to give you an idea of how MASSIVE this pump is, here it is sitting on the palm of my hand  I thought it was bigger too when I pressed the buy button on the website, but I like it all the same, just very fiddly

I think that's me for the day and the year, it's been a good'un, few engines built, few restored, few in triage awaiting attention in 2026.........

[PaulR]

Looks good so far.

I've enjoyed your adventures this year, especially seeing those real oldies brought back to life, and hope to see more in '26... Happy New Year!

[Sanjay F]

And I've enjoyed your many unique designs and builds and look forward to many more in 2026

wish you the best too 

[Sanjay F]

Both rear ‘wheels/cogs’ are now in place, made a few mess ups along the way, but recoverable……hopefully 

Everything is so minute with this little pump 

[Sanjay F]

Miniature egg cup and/or small trophy 

[Michael S.]

Looks good!

Are the two parts soldered or glued together?

[Sanjay F]

The two parts are soldered together now and have been polished, the flywheels (drive wheels) have been machined and bearings mounts have been glued on before drilling through. I'm still waiting on some appropriate tiny nuts & bolts to arrive before fixing them; they were tricky to drill and required guide holes in the top flange in order to reach down to drill them in the correct position.

The small drive shaft cog and larger cog needed some cleaning up and positioning before they meshed correctly, but we now have some rotation. Here is the partially completed 'Der kleine Prinz' (in my schoolboy German!  )

https://www.youtube.com/shorts/vssUznA7uxU

[Michael S.]

When several pieces come together, it looks really good. 

Michael

[Sanjay F]

Some more progress, finished off the 'top caps' which will like so many of the items on the this pump will be sealed with rubber 'o' rings.

Fitted a tiny oiler to the back and then came the bearing mounts. Boy what a job that turned out to be; I ended up having to use 12BA nuts and bolts and even using them there is no room underneath for the nut or bolt head. I ended up having to mill a slot with the smallest cutter I have underneath the bearing bracket in order to make them fit. You can see where the cut was made, but all good and who doesn't like looking for 12BA nuts when they ping off somewhere!