Herreshoff Steam Engine Fabrication @MIT

[Chris mcm]

Hello Jay
Well don't count on that. Remember Vapor's hull construction was very different from the Herreshoff drawing. Carvel planked and fastened with nails and roves. Not double planked and screwed as you would expect.
In Vapor's Triple engine the low pressure piston had a piston ring. On the drawing there is no piston ring and the piston is very light. There are no amendments on the drawing showing a ring at a later date. Vapors engine could have been rebuilt by others just like the hull. Interesting to me. The piston valves on my replica have no rings. On the MIT engine there are rings. The Hp and IP pistons on my engine do have rings similar detail to the MIT engine. HMCo seemed to do drawing of every thing they made and changes were recorded. Thanks to MIT Museum we are still using them today.
Regarding the lack of piston rings, I guess, the designer figured the steam pressure drop due to slippage past the pistons was minimal and compensated by the lack of friction had there been piston rings. Some one may have a better answer??


Chris

[Jay Greer]

Thanks Chris,
I am contacting Jon today to see if we can have a meeting of the minds and get "Vapor" running.
Incidentally, do you know anything about the quality of the Italian Lombardini marine engines? I am considering their 16hp Diesel for my H28 as the Universal died. It finally ended up with a perforated water jacket even though it had a heat exchanger. Please contact me off of this list.
Best to you,
Jay

[Canoeyawl]

I think you have chosen an important and fascinating project for sure; genius really. The few images I have seen are impressive indeed...

Only two main bearings yes, that was common.
As a machinist, I wonder how did they finish and fit the journals? Likely single point lathe work with special tooling, hand filing, fitting, and lapping.

[Chris mcm]

Hello Canoeyawl and Sam
I will be posting some photos from my phone. I have asked Jay Greer how to do it. I am not good at I.T.
Regarding your question about machining the crank shaft. I made two special lathe tools cranked left and right to avoid the balance weights. The finish and sizing can never be as good as grinding but I had no option. (This is a steam engine with max revs about 700). I managed to size it correctly and as you wrote. I used a file and lapping.
I wrote to Sam who questioned the forum about piston rings. I made my rings from Phosphor Bronze. On the drawing Sam posted they are cast iron and identified as such on the drawing. Not so on mine. The reason being. The original drawings were colored as most Technical drawings were. The prints supplied to me from MIT were Black and white. Without the color code I had to assume what metals were used. I should have known. I just never gave it a thought. You can see some of the drawings posted by Sam are colored.
Thanks for your interest.
Chris mcm NZ

I think you have chosen an important and fascinating project for sure; genius really. The few images I have seen are impressive indeed...

Only two main bearings yes, that was common.
As a machinist, I wonder how did they finish and fit the journals? Likely single point lathe work with special tooling, hand filing, fitting, and lapping.

[DoctorB]

Hi Chris, Jay, Canoeyawl. Thanks for the great input - it is definitely appreciated. We are on spring break now, so most of our students are away for the week. We did yield good bearing shells for the eccentric and main piston connecting rods, and we poured our third attempt at the crosshead on Friday. The crosshead has proven difficult, as it has a few changes in section from thick to thin to thick to thin, and we have had problems with shrinkage defects (Aluminum Bronze). We changed our risering scheme and will see on Monday if that helped. If we still have the same defect, we are going to try a different core strategy, which means modifying the pattern, corebox, etc. More anon.
We also re-poured that iron exhaust cylinder, having added more vents and risers.

The connecting rods are turning out great (1018 steel for those). We tried a technique using our waterjet cutter that worked amazingly well. Basically, we cut the 2-D profile (plan view), but leave the part tabbed in the stock. Then, we turn the stock on edge to waterjet the orthogonal profile. The intersection of the two cuts makes our part. We then bandsaw the part from the tabs - voila - and finish by hand. I'll let our student, John, post pictures when he returns.

The iron counterweights were cast, and the crankshaft is getting turned. I think Evan finished the throw before he left on break.

The stuffing box bits are done, and Sam did a really nice job with the pushrods and stanchion.

I am finally getting around to the bed plate, which I had intended to complete in January, but never could get it together. Once we get the bed plate (main base), we can start assembling and the project will look more like an engine and less a pile of parts. Eight weeks to go.

Thanks again for the input.

[Sailor]

When do you anticipate the students will complete the project?

[DoctorB]

When do you anticipate the students will complete the project?

MIT museum's new Herreshoff exhibit opens early Fall, so we really need to be done end of May. (Nothing happens over the summer.)

[Sailor]

Cool. Will follow on classes build something else equally cool? We're enjoying following along. Steam is such a cool motive force. Aside from sail of course.

[DoctorB]

The plan is for next year's class to pickup the Atlantic M&B.
I think i have someone restoring the Universal Fishrman, and then there's the Edson steerer or any number of other Herreshoff engines at the museum. Project list can outlive me easily.

[Jay Greer]

Thanks for the update Dr. B! Chris and I are followning this thread and your progress with great interest!
Jay

[DoctorB]

Per typical, I didn't get everything done that I wanted over the "break", but I did complete the bed plate patterns, core boxes, and cores. I have to build a flask, and should be pouring this coming week. The core is a monster, so I'll be hollowing it out a little for venting. We will be pouring the pattern upside down, i.e. with the flange downward. The top of the flange is the parting plane.

As a reminder, the bed plate is this part:


Fully assembled pattern:

The main part of the bed plate is constructed of four parts to facilitate removal from the flask. Also note the little round mounting bosses on the front face. This requires a side pull, hence the separate part. I figured that was easier than making another core.

Pieces that will be in the drag:




The core box was a puzzler, and I have no doubt there are easier ways to do this, but so be it. Because of the undercuts, I made the inside of the bed plate in two halves, each half being constructed of four sides that pull away from the core. Pulling sides away is infinitely easier than prying a core free from a cavity.







...continued...

[DoctorB]

Happy Passover, Easter, and Vermont Maple Syrup Day!

[DoctorB]

Tomorrow, we break free our fourth attempt at the bearing cross-head. We are plagued by shrinkage defects of Al-Bz, and decided to try leaded red brass, 83600. The top cylinder cap (iron) gets removed from its flask, too. Hopefully, we had some success.
More anon.

[nedL]

Our fingers are crossed

[DoctorB]

The cross-head, using 836 leaded brass seemed to fill great. Hopefully, we are all set and the student in charge of that one (Elizabeth, a.k.a. Bibit) will post pictures soon.
However, the cylinder cap didn't work out, though we know why, and have three things we are changing. Specifically, we are moving the sprue and gates to a fill from a thicker section, adding 4-6" head height to the flask, and may pour a little hotter. We are re-pouring this Friday. We use resin bonded sand for the mold itself, and, as a consequence, the surface finish is really nice. It's fun to see flames shooting out the core vents.

[marinesteam]

DoctorB,

You may want to take a look at C87300 Bronze (Everdur). It should be better suited for the service demands of a steam engine and the color is better than red brass. I'd have a chat with Pat at the Elliot Bay Steam Launch Co, he works with the foundries that produce his two launch engine casting kits. I'm currently in the process of building the York engine that he sells, so I'm interesting in the outcome of your project.

[DoctorB]

DoctorB,

You may want to take a look at C87300 Bronze (Everdur). It should be better suited for the service demands of a steam engine and the color is better than red brass. I'd have a chat with Pat at the Elliot Bay Steam Launch Co, he works with the foundries that produce his two launch engine casting kits. I'm currently in the process of building the York engine that he sells, so I'm interesting in the outcome of your project.

Great point, yes. 873 is our standard go-to, for sure. We are using it for the eccentric bearing shells and the piston connecting rod bearing shells. For the cross slide, I was thinking about the bearing characteristics of Al-Bz or Pb-Cu-Zn. As we machine, if we encounter voids, etc. we will probably move to everdur.

[Bob Cleek]

I may be wrong, but didn't H.Mfg.Co. use Everdur bronze for their engine castings? I believe the USN specified the same for their small launch engine base castings as well. I doubt they had Al-Bz available to them at the time, of course.

[DoctorB]

I may be wrong, but didn't H.Mfg.Co. use Everdur bronze for their engine castings? I believe the USN specified the same for their small launch engine base castings as well. I doubt they had Al-Bz available to them at the time, of course.

I would love to know the specific alloys, but there isn't anything other than 'bronze' in most drawings. The crankshaft, however, is marked "Alum-Br. shaft' - drawing from 1897 (which we are doing).

[J.Madison]

The technical challenge of the coring and molding is spectacular! Please keep telling us what you learn!

[HCR]

It is too bad that we do not know more about the bronzes used at HMCo and their properties.

We do know that N.G. Herreshoff conducted extensive tests about materials strength and corrosion and electrolysis resistance. He also had his brother, famed chemist John Brown Francis Herreshoff, analyze the chemical properties of materials for him.

Here is a page from one of NGH's design notebooks. It is undated, but context shows this page to have been written in about 1886. I am not sure where the original currently resides and only have a bad B&W copy. One day, I hope, we will be able to analyze more of these writings and be able to learn more.

Wonderful project and thread, this!

[Chris mcm]

Wow! Yes, I have to say this tread is certainly interesting. I am a wooden boat builder, a trade displaced due to the shortage of suitable boat building timber. I learnt to be a metal boat builder rather than work in plastics. My interest is still wooden boats and I loath to see so many being ruined (Loved to Death) by the modern use of bonding and anodes. My angle is, if you use copper and it's zinc free alloy's you don't require anodes on any boat. On a wood boat it is fatal as sodium Hydroxide (Caustic Soda) forms round the protected metal. Caustic Soda pulps the wood round the cathode. If you use Brass, Manganese or Tobin bronze in an electrolyte (salt water) the metal will certainly dezincify.
I am not really interested in the metals, they can be replaced. Not so the wood!
The reason I am writing is not to push my message but to help satisfy my curiosity.
Why did NG and Francis Herreshoff recommend Manganese and Tobin bronze for use in salt water. Also the Stones Propeller company in England made hundreds of propellers for War and Merchant ships from Manganese bronze. They certainly knew about Cathodic protection but did not use it to protect the bronze.
So what is different to the Manganese bronze made in 1900 and that we have today?
I believe it is due to the trace elements that were in the copper ore. Arsenic is one. Modern copper is pure. Most is used for electric transmission lines. Trace elements cause electrical resistance. So all copper is refined pure. The amount used in foundry metal is insignificant. So our Manganese and Tobin bronze once marine metals are little better than brass. If you have these metals on your wooden boat let them corrode and eventually replace them with Aluminium bronze,Silicon bronze or reinforced plastic. Don't use anodes or bonding to protect brass on a wooden boat. Change the metal that is wrong.
You can buy dezincify resistant brass DZR. Guess what. It is arsenic brass. You need to trust the source. Personally, I would avoid it.
I am sort of reluctantly known on this forum for my Herreshoff Steam Launch project. I promised to send photos. I sent some to Jay Greer to post on my behalf. There is a complication in photos taken from my phone. Further, I have a very interesting (to me any way) 1920 News paper article on the behavior of Muntz metal in salt water. I will try and work out how to post it.
Thank you.
Chris McMullen
Auckland NZ

[Chris mcm]

[Chris mcm]

Re the post on Muntz metal. Note the introduction and use of electrolytic pure copper. I am not a metallurgist but I understand less than one percent of Arsenic prevents the brass from dezincifying.
Years ago I asked the metallurgist at a local metal refining company about Arsenic. It certainly was not intentionally added to ingot metal in NZ.
The subject article is remarkably technical. I have not yet been able to find out the results of the research at the time. I hope this is of interest.
Chris McMullen
Auckland NZ

[Bob Cleek]

Yes, Chris, it is of great interest to some of us. I was surprised to see that "Herreshoff bronze," contains traces of iron, for example, and that the proportions of copper and tin were measured down to the hundredths of a percent. Even for a non-metallurgist like myself, it's very interesting stuff.

[DoctorB]

Yes Chris - please keep posting your detailed information.
@HCR, Re: "Herreshoff Bronze", I took a quick look through Metals Handbook, and the closest alloy would be Tin Bronze C902. Anyone with experience using this high copper-tin alloy?

[Chris mcm]

Yes Chris - please keep posting your detailed information.
@HCR, Re: "Herreshoff Bronze", I took a quick look through Metals Handbook, and the closest alloy would be Tin Bronze C902. Anyone with experience using this high copper-tin alloy?

I used Aluminium Bronze AB2 for the thin Bed Plate oil sump on my engine. I did my own moulding but used a foundry that was casting Aluminium Bronze every day. They seem to get it right.
AB 1 is stronger and more difficult to drill and machine. It also tends to get rust spots. I have always used aluminium Bronze AB 2 for all my bronze castings. It lasts indefinitely in sea water and for deck hardware it does not go green or tarnish. The foundry I use makes propellers from this Superior Bronze.
My patterns were wood just as Herreshoff Manufacturing made them. For one off work like this loose pieces and rammed up cores are used. The design is very complicated and the drafts man gave no thought about how it could be built. I am a woodworker by trade. I had made relatively simple patterns in the past but nothing like this.
I want to send some photos but can't seem to make it happen. I have Windows Ten and Picaso.

[DoctorB]

I used Aluminium Bronze AB2 for the thin Bed Plate oil sump on my engine.

AB2 is our C95800, if anyone's wondering. We've had bad luck with shrinkage defects using C95400. 954 has more aluminum and copper than AB2, in lieu of iron. Beautiful surface finish though.
Our plans call for an iron bed plate.

[DoctorB]

Here's the state of the engine - in process, but a reasonably comprehensive picture.


The crankshaft eccentric will be done next week (Evan), the cylinder caps have to be re-poured next week (Shirley), we had a successful piston and valve pour this morning (Sam), and the bed plate is slipping into next week (me). Notice the eccentric connecting rod - I think that is a really great part, and the power piston connecting rods are on their jig plates for machining (John). It's coming together, but much remains to be done.
I forgot to add the six or seven bronze stuffing box parts to the picture. We used our new toolroom lathe with NC threading, and the parts are beautiful.

[nedL]

Pretty! Oh,.... and Cool!

[Jay Greer]

Most impressive! I am reminded that L. Francis Herreshoff once told me and the owner of "Vapor" that his father was the only one that knew the secrets of his engines and that the knowledge, apparently, passed on with him when he died. This is the reason that your own work is so very important here.
Jay

[achen986]

Hi everyone! My name is Annie and I am also working on the engine with DoctorB, Emily, and Sam, and I'm also a senior studying Mechanical Engineering at MIT. I recently finished the main connecting rod bearing shells for the crankshaft and just started on the valve sleeves.

Since I haven't done much with the valve sleeves yet, I'll talk about the beginning part of my process for the bearing shells:

So for this part, I did two different pours. For the first pour, the patterns we used were quite close lengthwise to the final dimensions of the part. There was additional material to accommodate for shrinkage and post-machining, but not enough. As you can see below, there was some trapped gas in the narrow corners which produced some pretty gnarly results. We are using silicon bronze (Everdur) for this part.



For the second casting, we made new patterns with extra material on the ends. I'll post a comparison photo of the two patterns in a later post. The pour didn't fill the pattern completely, but it filled enough such that I still had material to machine off. Overall, the casting turned out great! The shell in the foreground is the upper bearing shell (characterized by a flat top flanges) and the one in the background is the lower bearing shell (rounded top flanges).



Here are a couple of close up of the parts. The first and second shows the risering for the upper shell and the surface finish. You can also see the mini riser we tried integrating into the pattern with varying levels of success (the one for the upper shell didn't fill completely, but the one for the lower shell did) . The third photo shows the finish we got for the bore where the crankshaft will sit. We'll babbitt this later.





I've already finished machining this part, but I'll post more photos as they're edited and update again soon!

[dberrett]

My name is Don Berrett, a volunteer at Herreshoff Museum. I am involved with developing a steam section for the museum.


We are presently building a replica of launch #199 in which we will display the boiler and a triple engine of the same vintage. This link is a blog we have produced that shows information on the engine, boiler and the boat we are building.


https://herreshoffsteam.wordpress.com/


We are at the point where we need to determine how to tie the Marsh pump, engine and boiler together. There are pieces of information available in the drawing for the hull and other drawings we have been able to find. But we need more details on how the boiler is plumbed and how to properly tie it into the rest of the propulsion system. So I was wondering if you might have any information (including pictures and drawings) to help us along?


Thank you for any help you can provide!


Don Berrett
Portsmouth, R.I.

[Jay Greer]

Don, I just sent a reply to your private message. Please let me know if it arrived as I have been having mail problems of late.
Jay

[dberrett]

Jay
I see a private message from you but no text in the message other than my original text to you?

I will reply with a private message again with my email in it
Don