View Full Version : How would you make this crankshaft?

Peter S
11-03-2003, 04:09 AM
I took this photo earlier in the year while visiting a small museum at Port Chalmers, near Dunedin, here in NZ.

This is an old air pump, one of the hand cranked variety used to supply air to a diver.

The crankshaft is very interesting, it appeared to be one piece, finely finished all over and notice how the crank 'webs' are tapered - it is a nice piece of work.
To give some idea of scale, the crankshaft is roughly 600mm or 2ft between the main bearings.


[This message has been edited by Peter S (edited 11-03-2003).]

Ragarsed Raglan
11-03-2003, 08:00 AM

That's an interesting crank! I would have thought that this crank was possibly a tube fabrication, the tapered big end 'webs' being developed & rolled to give the taper form. Is there any evidence of welding at the 'mirror' bends (the 45* joints), and is there any evidence of welding along a seam for the tapered webs?

Is the crank hollow? I know most museum displays have a prominent notice saying "Please do not touch", but in the interests of engineering research, a 'tap' with a finger knuckle would have been helpful!

Why would the crank be hollow? Is this air pump set a portable unit?? i.e is it weight sensitive? But, a bit of inertia in the crank would seem the ideal way of getting 'over compression' but then again maybe the old diving suits didn't need 'compressed air' just an air mover? I seem to remember from my past experiences with SCUBA diving that 32ft of water exerted 1 Atmosphere of air pressure on the human body, so the other side of the argument is that for every 32ft of depth you would need <15psi gauge just to breath 'normally'.

RR (confused!)

11-03-2003, 10:27 AM
Those "corners" seem to suggest that the pieces were machined and then maybe hard-soldered together. Otherwise that "3phase" crankshaft would be difficult to machine like that.

It would seem pointless and very difficult to finish it like that in the solid, but both easy and sensible if the pieces were assembled.

11-03-2003, 10:45 AM
Sure looks assembled to me. Doweled maybe, then silver soldered? Doesn't look like you could get any hard out of it with out it folding up on ya.

Paul Alciatore
11-03-2003, 12:50 PM
Seems like it could have been cast or perhaps forged and then the bearing areas machined. If it was a slow speed (hand cranked) pump then the bearing areas need not be that accurate. Perhaps just ground to fit with abrasive.

11-03-2003, 01:15 PM
I think it must have been intended to be used with a rigid diving suit. They were first devleoped in 1873 and only required air at one atmosphere pressure. In that case then the pump is just a "air mover" rather than a compressor and would not require a very strong crank.

Dr. Rob
11-03-2003, 03:11 PM
Is there anything to indicate that this really is the original crank, as opposed to a newly-fabbed restoration? Seems to me, that a machine that old would've rusted to bits after a life on the high seas. That crank looks brand-new and TIG-welded to me.

Regardless, that really is nice looking. Love the taper. Inspirational, even.

Peter S
11-03-2003, 05:36 PM
Unfortunately, the pump is now about 1000kms away from where I live, so I can't go back for another look! However, I was particularly struck by this crankshaft, and looked closely at it.

I wish I had tapped it to see if it was hollow, however, there were no seams or welds visible, nor the slightest indications of any joins or part lines, and it looked to be an old, original part.

I have to admit, at first glance a built-up construction seems most likely, however considering that it is a vital part in keeping a man alive under water, my guess is it would have been built strong and safe as # 1 priority, lightness not as important.
I really need to get some more information from the museum, even a date to find out what kind of welding options were available at time of manufacture.

A local museum here in Auckland (MOTAT) has a similar vintage set-up with which they did demonstrations (some years ago), they had a large tank of water, one guy pumps, the other gets suited up and climbs into the tank. The suit used is massive with one of those bolt-on type helmets, lead weighted boots etc. From memory that suit and pump was Siebbe Gorman (sp) pioneers in diving.

11-03-2003, 05:52 PM
That sort of pump could also have been used to supply air to a diving bell. It certainly isn't something where you would skimp on quality. A lot of the early diving equipment inventors found out the hard way that thier inventions had fatal flaws.

11-03-2003, 06:25 PM
If it's not built up, I'd guess it was forged, then the surfaces cleaned up by hand.

But as Oso says, the corners seem more likely for a built-up job, less likely for a forging.

11-03-2003, 07:52 PM
Are those allen cap screws on the mains?

Maybe a forged crank,kinda reminds me of a T-model crank.

John Garner
11-03-2003, 10:52 PM
I just can't hold back anymore . . .

Anyone who's been through (military) officer training knows that the crankshaft results from ordering "Seargeant, get someone going on that crankshaft!"

Seriously, it's a beautiful piece of work that I'd guess started life as a forging, but I wouldn't rule out a plaster-mold casting.


11-03-2003, 10:59 PM
"Are those allen cap screws on the mains?"

GOOD eyesight! I didn't even notice! They sure do look like allen cap screws. I though those where developed around the 1930's or 1940's.

11-03-2003, 11:31 PM
I would guess the socket head cap screws are bogus for this unit. Steel would be out of place among all what appears to be bronze hardware. The rod screws look correct. If the crank is legit it may be a lost wax cast marine bronze piece. JMHO

Neil Peters

11-04-2003, 02:23 AM
I get the impression that it's cast, and the original 'crankshaft' made from wax, or other material, and pieced together, accounting for the 'homemade' look. The lack of welds or other methods of joinery support this theory. I wonder about the material, sort of looks like stainless, or maybe some brass alloy. It must be chosen for it's non-corrosive quality, or it would be a forging out of cast iron or steel, since that was very common then. Weight didn't seem to be much of a factor in those days, so I don't think it would be hollow. If it's brazed, it sure is a nice job of it. There doesn't seem to be any significant ammount of machining done to it to clean it up. It's cast, using a special alloy, using a cheaply made master, that's MHO.

Bill Cook
11-04-2003, 10:04 AM
Looks like the ultimate crank design for a file finnish - fit and cosmetic.


[This message has been edited by Bill Cook (edited 11-04-2003).]

11-04-2003, 11:20 AM
I go with investment casting using lost wax process. The material is almost certainly nickel silver. Nickel silver is that color, has excellent corrosion resistance, the required strength and melts almost 800 degrees F below stainless. It is also a compatible bearing material for the brass/bronze bearings. Nickel silver also has excellent hand machinability and a casting could be easily cleaned up with files to the finish shown without leaving marks. I've used it in jewlery making and it's nice to work with.

I was watching a show about diamond divers in Africa the other night and some are still using that sort of pump.

One more thing, the tapers make for clearance for the connecting rods.

[This message has been edited by Evan (edited 11-04-2003).]

Peter S
11-04-2003, 05:37 PM
I e-mailed the museum, asked them to check if solid etc. Here is the reply I got;

"The crankshaft is solid and it must have been welded. I can see some file marks on it.
The makers plate reads- C.E. Heinke, Sub Marine Engineer, 103 Gt Portland St, London. There is no date. If I find out any further information I will let you know."

The material gave me the impression of being steel.

I don't recall the file marks, maybe it had been draw filed to remove corrosion (draw filing is good for this sort of work)

I did a search on the internet, wouldn't you know it, there is a whole world of old diving gear collectors and users out there!

See the reference to Heinke at top of page.

Here is another site, has a good collection of news articles of the under water type.


11-04-2003, 06:05 PM
I still think nickel silver. That is consistent with the reply as well. Steel would corrode too easily unless stainless while nickel silver is very much the same color and appearance as SS. Nickel silver may be brazed or silver soldered/brazed very easily and it produces a very strong joint. An item like that may have been produced by reflow soldering/brazing of individual pieces considering the appearance of file marks.

It's much easier to work than SS and far easier to join with the less advanced techniques of the time. It is just as strong as SS with ultimate tensile strength up to 130,000 PSI!!!

Here is a quote from Matweb re workability:

"Excellent corrosion resistance. Excellent cold workability. Fabricated by blanking, drawing, etching, forming and bending, heading and upsetting, roll threading and knurling, shearing, spinning, squeezing, stamping and swaging."

It is also available as a casting alloy suitable for investment casting with a tensile strength of 55,000 PSI.

[This message has been edited by Evan (edited 11-04-2003).]

11-04-2003, 08:59 PM
I'm going to agree with Evan that it's nickle silver. That does make the most sense, given the visual, and the use. I didn't think of the term 'investment casting', but that also makes the most sense now to me. The reply from the museum saying 'it's solid and must have been welded', is a guess, and comes from someone who isn't likely to be a metalworker, but as a layman, says that it looks welded. But where are the fillets, the 'damage' in the corners, etc. That would be an awesome job of filing to get that look. It's investment cast, in nickle silver, I'll bet my desert on that now. If I'm wrong, tell me where to send the pumpkin pie.

11-04-2003, 11:18 PM
BTW, for those who may not know, nickel silver has no silver in it. It is basically brass with most of the zinc replaced by nickel, up to 27%.

11-04-2003, 11:25 PM
Possible, of course.

I opted for built-up on the basis that all the pieces could be cut from one length of rod, cut and milled with hardly any waste to fit together as they do.

If done that way, well, a bit of filing in the corners would not be odd, to get rid of small excesses. And the shape, with the corners, would come out of the nature of the material, as the pieces would form it directly.

The likely small 'specialty" production would have also suggested a built-up construction. Investment casting of nickle silver isn't done on every corner, and wouldn't have been so then.

The funny corners which are a natural for pieced, represent wasted material for a casting.

Against that is the idea of specialty construction done as a specialty casting for a particular purpose, in that way as the best way to satisfy the need. The corners might have been done as a form of 'fine finish" that they prided themselves on.

And there is the issue of a diving pump being pretty important. Do you really want to trust a pieced-up crankshaft?

BTW, DR Rob...Tig welded is exactly what it does NOT look like to me. And, if nickel-silver, only sulphur compounds really corrode it, so it could look "brand new" even after a long time. That would show good material choice.

[This message has been edited by Oso (edited 11-05-2003).]

Dr. Rob
11-05-2003, 02:55 AM
I really like the detective work being done here, but I ain't buying it. Allow me to reiterate my previous post.

If the museum guy had a magnet it would help.

11-05-2003, 11:18 AM
Not really. If plain old steel the magnet would stick and so would the rust. If SS the magnet may stick or may not, depending on the type of SS. If nickel silver the magnet won't stick, same as some SS.

To test this piece a nitric acid test will reveal what it is. One drop of diluted nitric acid placed on an inconspicuous spot will show no color change for SS, black or brown for steel and pale blue/green for nickel silver.


I wonder if you could convince the museum curator to do an acid test???

[This message has been edited by Evan (edited 11-05-2003).]

11-06-2003, 12:05 AM
I'm leaning toward monel.is been around for awhile,looks about right for color,and is real popular offshore.It could also be nickel plated brass

[This message has been edited by wierdscience (edited 11-06-2003).]

11-06-2003, 12:11 AM

Not much difference between monel and nickel silver. Monel has higher nickel and lower copper. They both test the same on the acid test. In the "old days" the alloy could have been anywhere between nickel silver and monel. Not much point in nickel plating brass when you can have nickel all the way through. The only way to tell the difference between monel and nickel silver is with a metallurgical analysis.

Also, if the nickel plating on brass wore off the bearings would be toast.

[This message has been edited by Evan (edited 11-06-2003).]

Peter S
11-06-2003, 07:46 PM
I forwarded the magnet and the acid idea to the museum, here is the reply from Peter Cole at the museum-

"Yes the magnet sticks. I think it is some type of stainless. Sounds very hard when tapped. No I don't think I will try the acid test".

11-06-2003, 08:05 PM
That seems to indicate it is made from non-austenitic stainless steel, either martensitic or ferritic.

It also could be steel with a plating, nickel or chrome most likely.

11-06-2003, 08:31 PM
Yep,I know Evan,same basic material,different english.

Could also be nickel plated cast iron,its used heavily in commercial kitchen equipment,Oster,Hobart,etc.

11-08-2003, 02:14 PM
The intersections of the throws to the main crankshaft don't intersect the way that I would expect it to if it were built up. I would have expected the main axis to remain one solid length while the the three throws are welded up at 120deg from each other. Then the main bar would be cut out at each throw and then dressed up. This would have probably resulted in a different look to the way the parts intersected though. I wonder about whether the parts are solid or not, or whether they would need to be. At 200' depth a diver would need air at 90psi and at a rate fast enough to keep his helmet fresh and bubbling. I wonder what HP would be required. Because the crankshaft is built into a wooden box I was thinking that it might have been needed to be portable too. Because the stresses aren't the same as an engine I was thinking it would be built up. Looks like a work of art.


11-08-2003, 02:22 PM

That pump was almost certainly hand powered with a max of maybe 30 psi. If it was used with a rigid suit or diving bell then it runs at essentially zero psi (well, a few) and just moves the air.

[This message has been edited by Evan (edited 11-08-2003).]

11-08-2003, 05:49 PM
Evan, I dove for pay in a "hard hat". We had a hand pump, and I worked under boats at Gulfport Mississippi. The boats were mostly shallow draft shrimpers. The jobs were mainly working on rudders or props or prop shaft seals. The time under water was maybe thirty minutes to an hour, depth of (to the bottom lip of the hard hat) was probably the boats draft , plus 18" for work space and less than 18 inches to bottom of helmet (total of maye 6 to 8 feet max).

We let boat owners pump for us to cut cost, if they would keep air coming (a steady string of bubbles) at all times. Few could keep up the pumping the length of time needed to remove the parts for repeatedly and to install after repair in one dive. (30 minutes to an hour max under the boat).

It is more than just moving the air when its a man pumping http://bbs.homeshopmachinist.net//smile.gif.

Once these two boat owner yayhoo's failed to keep the air to me (friend had home made scuba gear). The yayhoo's offered to dive if we pumped (ok by us cause we did it all by the hour). Ollie (friend) and I pumped a while, got tired. Ollie says to me- you pump alone a few strokes. I did. Ollie sat down by intake, lighted cigar in mouth and blew. THe divers soon came up, admitted we had kept air flowing, but at best it became foul in a few minutes. They kept air coming after that. It was work!

Our pump was two cylinders, with a handle that went up and down like a pump handle or rail road work car. Inside the helmet, the water came to near my chin when I inhaled and then back down when I exhaled. came up over mouth if i squatted quickly. every thing depended on the pumpers keeping a small steady stream of air rising. I can't make it sound like the work it really was, but it was hard work pumping air even that shallow.

BTW- it was just infrequent work to supplement the shrimping. Shrimping was also hard work http://bbs.homeshopmachinist.net//smile.gif. Ain't no gravy trains taking food from the water.

11-08-2003, 06:08 PM
Interesting story Steve. The point about a rigid suit or diving bell is that they are dry and use air at 1 atmosphere no matter how deep they are. They also have some air storage capacity. Under those conditions it really is "just moving air".

11-08-2003, 08:32 PM
I can understand a diving bell needing just a little pressure to just move the air thru it and the same with a rigid diving suit IF they both had a return airline to the surface, but if they exhausted the airflow directly to the water outside wouldn`t they and the old suits that consisted of a helmet and rubberized flexible suit require the air pressure to be equivalent to the pressure the water exerts on the diver in order to force the air down to the diver? If the diver's hemet was at 100 feet below the water surface, wouldn`t the air pressure at the surface have to be 43.25 lbs/in2?

11-08-2003, 11:10 PM

You are correct. The rigid suits and diving bells did have a return line for the air and did use air at 1 bar. If the air is exausted to the water then of course it must exceed the pressure of the water. Rigid suits are in use today and the problem of the joints locking from pressure has been solved with ball joints at all articulation points that are not affected by pressure. These were invented by Hard Suits Inc, in Vancouver BC, Canada. These suits are self contained and can go down to 2000 feet!!!! See here:


11-09-2003, 12:58 AM
These old diving suits were not the same as a rigid suit. Even if there were a return line to the surface for the air it would not have made a difference. Evan is wrong about it being a 1 atmosphere proposition and an easy pumping job. The problem is precisely the fact that it isn't a rigid suit. Even with a helmet full of 1 atmosphere air (assuming that) it would be impossible for the diver to inhale it.

11-09-2003, 01:31 AM

You seem confused. I never said that a flexible suit could use 1 atmosphere air. In fact I never mentioned flexible suits ('till now). The rigid suit was invented in 1873. A rigid, fully enclosed RIGID suit with a return line only needs 1 atmosphere pressure. Obviously, a flexible suit allows the water pressure to bear upon the diver and therefore requires that the diver need air at the pressure of the water bearing upon him. The biggest problem with rigid suits in the early days was that the pressure of the water would lock the joint designs of the day so that the diver couldn't move.

Closed diving bells are a different matter and operate at 1 atmosphere. They need air and in the early days this was supplied by an air pump that merely needed to circulate air to the bell. Probably the biggest problem was making hoses that wouldn't collapse from the water pressure.

11-09-2003, 03:45 AM
Well if this problem was solved in the 1800's and everything else is as you said then I must be wrong. Sorry.

11-09-2003, 03:52 AM
I'm sorry Evan,
I was thinking in the time of the Submariner that built that crankshaft. This was also the time of handcranked air pumps and many years before a workable rigid suit.

Those early rigid suits were pretty cool but whether they solved the problem or not I don't know. Lots of joints to seal


[This message has been edited by SJorgensen (edited 11-10-2003).]

11-09-2003, 06:47 AM

11-09-2003, 11:25 AM
To me, a diving bell is a container, open on the bottom, You can go in and out- via the bottom hole- with ease. no air locks needed.

A "bathysphere" (spelling error?) is closed and windowed and MAYBE an airlock for entry/egress. Air pressure inside may be any thing from vacuum to higher than ambient at the depth you are. Atmosphere inside can be any thing. It must with stand high pressure differentials if it goes deep and keeps one atmosphere inside. If it breaks you die! You would at depth probably be shoved right back up the air line and come out like a tooth paste from the tube.The supply pump is just moving air in and out. Low volume, low pressure.

The diving bell requires air pressure to the EXACT pressure of water level.(More pressure and the water level goes down or a string of bubble come out)(less pressure and water level rises- too little pressure and the water fills the bell and goes up the hose ''til water and air pressure equal.
Break it and probably duct tape would keep water and air separate (air pressure is same as the water pressure at the bottom of the bell, so the air pressure is above the water pressure (by, at most, few pounds per square inch). If a crack comes the air would try to go out and water would come in from the bottom (not through the crack). The supply is high pressure, high volume (whatever I mean by high volume). Remember though- when you breath one pint of air at several ATM, you are taking in several normal pressure pints per shallow breath. You cannot over pressure a bell- air just blows out to no use. The occupants can swim in and out. But the occupants have to decompress same as a diver must.

Forces on a bathysphere and a bell are opposite. The bathysphere must resist pressure (BIG PRESSURE!) from out side. Bell must resist small pressure from inside. In other words the bell skin is actually in tension, the bathysphere in compression.

BTW: The rag suit just keeps you dry (warm hopefully). Just little over pressure for any reason and you are spread eagle (arms and legs straight and parted)- been there done it and even for fun it was scary to me. THe hard hat has a "chin valve" to release pressure if you are in suit and spread. No suit? no problem!!!. So even in cold weather i would not wear a damn suit for any reason. I don't think you could find enough hand holds to stuff me in a suit. And it would be a slippery job holding me. I knew I was going to be spread eagle and I still damn near panicked. I bet three was not 1/4 PSI pressure difference, but the are so many, many square inches involved. So you can "bend" an arm a little, and no force against you. Just can not bend more- no place to push or fight-just will not bend more. relax and you are spread out. Hold the bend and you are tired all over not just in the bent arm.

The "hard hat" was brass with three or four windows (memory fails on the number- but they were small). Many dings and repairs were just soft solder. The actual pressure a hard hat sees is alway near zero. A glass jar or gum ball container or thin plastic would suffice. I have no idea why the old stuff was so confining, heavy and big bars across the windows.

BTW again> The pressure at your feet is couple of pounds per square inch higher than at the head. So the vent is low on the helmet, the suit is pretty well fitting at the arms and snug at the legs. No problems with the pressure- the pressure differences would be the same if you were naked. But raise an arm above your head and the suit gets full of air in the arm and you can almost pull your hand back in to he sleeve (can not because the wrist is tied) the bloated glove makes it hard to twist a nut. I ONCE took a glove off (being a wise ass) and cinched the wrist band. Air went out when i raised arm (expected) but the damn air went in big globs, water came in. No sweat gents, you can not drown so long as the air comes in faster than the the water up in the hat. just so long as the "stream of bubbles" goes up you are safe. So I put the glove back on, figured i would not brag about my adventure, no one would ever know. Ever notice the big boots the pictures show on the old divers suits? They must hold some thing less than 100 gallons of water per boot. when I climbed out on the wharf, I needed help. Boots full of water. Ollie suspects a leak somewhere. He never found a leak, I never told where the water comes from.

As you might suspect from reading between the lines, I have am claustrophobic but I manage to keep it under control (IE: I fear but do not panic). But no suits for me, I went down at a ship yard (Subic Bay) in dive bell (of the sort I described) and it was fun. Went down in Dress clothes, came up wet from condensation only. Why did I go down? cause I was invited!!!!

The above is all from memory, If I have mis remembered feel free to correct me right here. "it is what you think you know that ain't so that gets you killed".

11-09-2003, 11:40 AM

I defer to your superior wisdom and experience. I mis-spoke, I did mean bathysphere (your spelling is correct).

You have been there, I have not. I have only scuba'ed.

Great story. I'm glad to see you are still alive!

11-09-2003, 01:58 PM
Evan, I spent a year on Swan Island in the Carribean. Not much SCUBA for me but I was good skin diver (fishing). No town on island, maybe ten "natives" and a weather station bunch (less than 10 poeple), and us (Philco types).

When bored I would swim way out and bring back some fish. Had a buddy who could swim as well as I but he could not go very deep. Tried to us tanks but then he was too slow. So he rigged a scuba tank from a small carbon Dioxide cylinder. Just fit his back. Now he could keep up, and when he wanted to look around on the bottom, he went down, needed a breath so he inhaled. Suprising to me but I think one breath of ait lasts longer when you breath it down low. Fisrt off, You would say yes dummy, he got more air. but i under stand its a ratio thing where acids build and that it was just my imagination. any way he could stay longer and deeper than I could. A fun year in many ways. Those of us on Swan island were mentioned by a chapter in "TheInvisible Government"- the chapter is "the CIA's guano empire" (thatwas Swan Island). Trips to Belize, Caymans, Cozumel (long before it was popular). Not much prettier than clear water, coral reefs undisturbed by man and the bright fish. Longusta makes fine eating and we kept sea turtles for eating.

Some day........ http://bbs.homeshopmachinist.net//smile.gif

11-09-2003, 07:38 PM
All this talk of pressure has me thinking,are they sure this isn't a hand cranked bildge pump?

Neat story Doc,its good to here of the Gulf BC(before cruiseships)

11-09-2003, 08:30 PM
Weird: You may be right. i keep thinking of those three pistons, and the area/stroke (displacement per revolution) involved. Seems to me to very low pressure if man powered, never considered a bilge pump. Sure would want a good screen if it was a bilge pump. Bilge pump (if the waste line is under water deals with very little head (more than a foot or so and they better be nailing hatch cover together- gonna be a wet night) and the pump just moves water, hoses recover the energy. Then again, Evan may be right- air to a rigid suit would be easy- but the volume (three pistons) would supply several divers. I sure ain't gonna be under water sharing air hoses with ANYONE who is fool nuff to go where a rigid suit is needed. He pop his suit, be squeezed back up his line and down mine. His blood and guts in MY suit!!! Nope!. Course maybe they had check valves and other stuff to keep my air coming. Small problem though be cause I won't go!.

Regardless- it is pretty and interesting- and I am glad to see it regardless of the use.

[This message has been edited by docsteve66 (edited 11-09-2003).]

Desperate Design Student
05-09-2005, 08:34 PM
I'm doing an assignment where I have to research the Heinke dive suit at Port Chalmers in preparation for an exhibition on it at the end of the year. Information on this particular suit is pretty illusive. I was just wondering if anyone could point me in the direction of some detailed information, actual experiences of the use of the, or ones like it, suit, or anything really( its a bit off topic sorry but as my name suggests I'm getting pretty desperate)

3 Phase Lightbulb
05-09-2005, 08:59 PM
<font face="Verdana, Arial" size="2">Originally posted by Oso:
Those "corners" seem to suggest that the pieces were machined and then maybe hard-soldered together. Otherwise that "3phase" crankshaft would be difficult to machine like that.</font>

I don't remember making it, but if I did then I'm sure I TIG'd it together, cleaned it up, and re-ballanced it.

Peter S
12-07-2013, 01:05 AM
While searching for posts on crankshafts, I came across this old one....and the photo link no longer works, making it all a bit pointless.

Here it is again.

BTW, the image is still on Photobucket as originally uploaded in 2003, never touched by me, but a few years ago PB gave all the images new addresses or otherwise did something to ruin the links.

Maker plate: C.E. Heinke, Sub Marine Engineer, 103 Gt Portland St, London

http://img.photobucket.com/albums/1003/PeterS/crankshaft.jpg (http://smg.photobucket.com/user/PeterS/media/crankshaft.jpg.html)

Mike Burch
12-07-2013, 03:51 AM
Peter, thanks for the photograph. I've read this thread despite being unable to make the original link work, so it's good to see the thing the discussion is actually about.
To my eyes, the holes in the wooden lugs sticking up in each corner look like insertion points for carrying poles, so I think the thing is supposed to be portable.
It's in a lockable wooden case, so I think the chances of its being a bilge pump are slender. Bilge pumps are nearly always permanent fixtures (and they should NOT have their exits below the waterline, because of the danger of back-syphoning). And why would you keep a bilge pump locked?
As for the construction of the crank, it absolutely screams "made up" to me, with those neat near-right-angles. Why/how would you have those sharply-detailed corners on a casting, when it would be stronger and easier to round them off? And machining it out of solid would surely be hugely wasteful. (Of course, I'm not a professional, so I could easily be talking nonsense.)

J Tiers
12-07-2013, 09:38 AM
Built-up would be fine, but how it held together is another issue. A fine line of silver solder or the like would explain much of the mystery, but isn't the way I would think of making something as important as a diving pump. The name "Heinke" also explains a lot, since it is germanic, and German machine work *would* be "mysteriously good" at the probable time of that thing being made.

Could also be due to the use of files.... look at the efforts expended on large engines to blend and smooth. Compared to some of those, this would be child's play.

12-07-2013, 09:53 AM
I have no idea how the crankshaft was constructed but the picture has opened a door for me as to how to supply a very steady, low pressure source of air to power a Harmonica reed tuning fixture. I have been stuck on using a bellows system, but I could not see how to make it supply a never ending smooth air supply. Mystery solved, three pumps driven by a 120 degree crank.

michigan doug
12-07-2013, 10:04 AM
Or pump to a bag with a weight on it. That's how our pipe organ at church works. Has an electric compressor, and the original hand powered bellows, both feeding into a weighted bag. Changing the weight changes the supplied pressure. There is also the small scale manure to natural gas schemes where they use a smaller barrel inside a bigger barrel. The annular space between the two barrels is filled with water to provide the seal. The smaller barrel is open to the bottom. Pump your air into the mouth of the smaller barrel/container.

nice pic, good discussion.


12-07-2013, 05:14 PM
Iíd put money (not much though!) on the crankshaft being forged/bent, and then filed. An insane way of finishing a crank, but a tour de force by the filer. To fabricate it by soldering or brazing would seem very risky. It was, after all, a safety-critical item.

Mr Tiers: While agreeing about filing, I'll have to be disappoint about the pump's origin. The firm C. E. Heinke was British, not German. There was some Prussian influence, though - Charles Edwin Heinke's father had moved to London from Poland in the early 1800s.

Another early London maker of diving equipment was Sadler & Co. There's a Sadler pump for sale in the link below which has a very similar three throw crankshaft. If you zoom in, you can see that the 'knees' arenít sharp cornered, which, I think, is more consistent with a forging than fabrication:-


12-07-2013, 05:59 PM
If the sections were both pinned together and brazed I think it would hold up quite well. There would not be a lot of stress on it. It was turned by hand and only had to deliver enough air for breathing.

12-07-2013, 06:13 PM
http://i3.photobucket.com/albums/y54/Asquith1/JDSiebe01_zps99fed0a5.jpg (http://s3.photobucket.com/user/Asquith1/media/JDSiebe01_zps99fed0a5.jpg.html)

In 1961, Heinke were taken over by Siebe, Gorman & Co. No prizes for guessing how Siebe made this crankshaft! Pump on display at Vancouver Maritime Museum.

Slightly different design from Siebe, Gorman, this time at the Maritime Museum of BC:-

http://i3.photobucket.com/albums/y54/Asquith1/JDSiebe02_zpsd6bbe056.jpg (http://s3.photobucket.com/user/Asquith1/media/JDSiebe02_zpsd6bbe056.jpg.html)

Closer view:-

http://i3.photobucket.com/albums/y54/Asquith1/JDSiebe03_zpsa4f90a58.jpg (http://s3.photobucket.com/user/Asquith1/media/JDSiebe03_zpsa4f90a58.jpg.html)

Siebe became BTR-Siebe, who renamed themselves Invensys. British conglomerates like to give themselves daft names before disappearing altogether.

12-07-2013, 07:58 PM
Possibly the pretty crank is cupronickel, or 'monel' which I believe was/is a trademarked name for a slightly altered alloy of the same stuff. Both have the same silvery look, and were used for cranks, propellers shafts as well as fuel tanks and piping.

J Tiers
12-07-2013, 08:08 PM
Mr Tiers: While agreeing about filing, I'll have to be disappoint about the pump's origin. The firm C. E. Heinke was British, not German. There was some Prussian influence, though - Charles Edwin Heinke's father had moved to London from Poland in the early 1800s.

That is the germanic influence..... I am not at all disappointed, as the address given was already obviously local to UK. The point is not the actual country of origin, but the likely background and influence on the maker. In this case, apparently "East Prussia" in family origin, as are many Germans, including some of my own relatives.

Mike Burch
12-08-2013, 01:34 AM
Monel is still used a lot in the marine industry. For example, it is relatively kind to aluminium in a salt atmosphere, so properly-built aluminium masts use Monel pop rivets for fastenings.
Cupro-nickel is a very good material for hull plating, because it's strong and weldable, and because of its high copper content it never needs anti-fouling. Unfortunately it is hideously expensive, so is rarely used.

12-08-2013, 08:25 AM
I had an old Popular Science magazine once showing how Chrysler made V8 cranks by forging them flat and then (with the crank still hot) twisting(!) the throws to their correct orientation. This was vintage 1950-1960's. I sold my collection, otherwise I'd look it up for you.