# Sterling Fan Build



## b.lindsey (Nov 16, 2008)

Finally over the last few weeks I have been able to spend some time making chips again and one of the back burner projects I have wanted to do is Jerry Howell's Mini Sterling Fan. Just though I would share a few photos of progress to date.

Here are the three displacer parts not yet assembled.






The power cylinder.





The gland for the displacer rod and power piston insert.





What will be the top of the stand once those 4 13 degree 5-40 holes are drilled and tapped (still pondering that setup).





The bottom side of the displacer cylinder.





The power cylinder again with the cold cap and bearing standards installed.





And finally all the parts so far shown on an 8 1/2 x 11 sheet for size reference.





The hot cap is nearly done and I hope to finish that and get a good start on the crankshaft today. If there is any interest I will post additional pictures as progress continues.

Regards,

Bill


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## b.lindsey (Nov 16, 2008)

Just noticed after posting...the sixth picture should say "displacer" cylinder assembly rather than power cylinder.

Bill


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## hitandmissman (Nov 16, 2008)

Of course there is interest. Please keep the build info and pictures coming. Great looking work.


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## Divided He ad (Nov 16, 2008)

Well I'm watching and very interested Bill ;D
Nice neat parts you have there.... I always think it must be a bit interesting putting fins into square stock?! 


Keep 'em coming 



Ralph.


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## carbide_burner (Nov 16, 2008)

Looking good! I'll definitely follow. My first project, a Laminar Flow, is nearing end, and I think my next project will be a Stirling fan. I'm looking for drawings - any suggestions?


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## shred (Nov 16, 2008)

Nice work. 

Btw, I skipped the angled holes and baseplate on mine: http://www.homemodelenginemachinist.com/index.php?topic=1146.0

Carbide, when looking a while ago I only found two sets of easily locatable Stirling fan plans-- Jerry Howell's (he has a couple sizes) and Senft's Moriya (published in Steam and Stirling book 1). Moriya has better step-by-step instructions if you like those.

Pretty much any Stirling motor (LTDs excepted) will run a fan instead of a flywheel, so you're not limited to those if you want to get creative. 
The stirling plans in the downloads section is very similar to the Moriya core, though it has been somewhat Anglicized.


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## Brass_Machine (Nov 16, 2008)

Bill

keep the pictures coming!

Eric


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## wareagle (Nov 16, 2008)

It looks like you have one heck of a start there! Please take us along for the rest of the journey!


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## JMI (Nov 16, 2008)

Very impressive and clean machining. It is what I strive for and sometimes get.

Questions about the power cylinder. The fins were done on a lathe with a "parting tool" type cutter? The material it is made from is ?

Thanks

Jim


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## b.lindsey (Nov 17, 2008)

Thanks to all for the nice comments. As to the power cylinder it is made from round mild steel large enough to mill down the four flat edges which form the base leaving a slight radius on each corner. I just used some stock I had. the fin spaces were cut on the lathe with tailstock support. It just happes that the .040" fin space called for is the same as the cut off blade width on my Sherline lathe. All of that was done before parting off from the original round stock. One of my most used accessories is an eight sided adapter which allows the lathe chuck to be mounted to it and transferred to the mill vise to cut the flats and then transferred back to the lathe for cutting fins, parting off, boring, etc....all without ever having to re-chuck the work.

The fins on the displacer cylinder on the other hand were cut with an .040 slitting saw using the rotary table and mill.

Will try to post some pictures of the hot cap this evening. It was made similarly to the power cylinder (less the fins) but out of stainless. I was worried about the wall thickness while boring it out. It narrows down to .0125" at one point but it turned out well and seems plenty strong.

Bill


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## b.lindsey (Nov 17, 2008)

Shred,

I gleaned several ideas from your previous build post so thanks for the link back to that, especially how you attached the blades to the fan hub. As for the base, I will probably stick with the original design but modifying the inner diameter of the base to be a close fit to the dummy doorknob from which the alcohol burner will be made. The 13 degree holes I will have to do on the bridgeport or either purchase a tilting table capable of holding the 4" rotary table at the same angle. Anyway...some things to ponder over the next few days.

Bill


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## Brass_Machine (Nov 17, 2008)

O/T...

Hey Bill, you got a thread on the engine in your avatar?

Eric


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## b.lindsey (Nov 17, 2008)

I just have the hot cap to add to the pictures tonight...unfortunately the day job gets in the way during the week. At any rate the stainless turned well even on the Sherline, it just took a lot of passes of about .005-.007 to reduce the diameter of the rod stock from 1.250 down to .700...pretty tough stuff!

With the hot cap done and the base squared off... time to bore out the inside





And the finished (almost) hot cap (still have the 4 mounting holes to drill.





Hopefully more to add tomorow night.

As to your question Eric, no there isn't a thread on the engine shown in the avitar, but i can post some pics if you wish or you can see a video of it running on the website or I can try to post the video here if that is easier. Even as I am working on the fan project I am also working on a half size version the that same engine just because I like 'em smaller...plays the devil on your eyesight though or is that just older age creeping up...lol.

Bill


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## Powder keg (Nov 17, 2008)

Looking great!!!

Wes


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## Brass_Machine (Nov 17, 2008)

wlindiii  said:
			
		

> ...
> As to your question Eric, no there isn't a thread on the engine shown in the avitar, but i can post some pics if you wish or you can see a video of it running on the website or I can try to post the video here if that is easier. Even as I am working on the fan project I am also working on a half size version the that same engine just because I like 'em smaller...plays the devil on your eyesight though or is that just older age creeping up...lol.
> 
> Bill



Absolutely... Please do a picture thread on the other engine. Please!

Eric


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## b.lindsey (Nov 19, 2008)

Eric, I did post some pictures of the avitar engine in another thread in the photos and videos section. Should be lableled as OPV Engine. Hope to have more pics in this thread tonight.

Regards,
Bill


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## b.lindsey (Nov 21, 2008)

Just a little progress in the last day or so. The fan blades are at least cut and edges smoothed but not finished or polished by any means.

Here is a picture of the sandwich...four brass blanks .015 thick and the paper template on top. This was after bandsawing the excess stock and sanding down to the template outline so they would be as identical as possible.





The after de-gluing, cleaning in lacquer thinner, and de-burring the sanded edges. Once the hub is made and the blades attached, the final diameter should be about 5".


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## b.lindsey (Nov 23, 2008)

Made a little more progress over the weekend after losing several hours hunting for the fan blades (shown above) which I had inadvertantly thrown in the trash with some junk mail. Fortunately they were found !!!

Finished up the mounting holes in the power cylinder, hot cap, and displacer cylinder so now everything attaches as it should.











Then began work on the crankshaft and got that done other than the third crankdisk for the power piston.






Then I assembled all the main parts to get an idea of what it will all look like assembled. So far so good.






Next will be the fan blade hub, the remaining small parts (con rod bearings, links, etc.) and the base. Hopefully another weekend's work and it will be ready to try out.


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## Powder keg (Nov 23, 2008)

That is turning out AWESOME!!!!!!

Wes


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## JMI (Nov 23, 2008)

wlindiii  said:
			
		

> Made a little more progress over the weekend...



wlindiii,

Where did you get that chucking device shown it the photos? It looks very interesting.

Thanks

Jim

P.S. The engine looks great!


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## Mike N (Nov 23, 2008)

:bow: Awesome workmanship! :bow:

I just ordered a set of plans from Jerry Howell. It looks like a great winter project. Is the crankshaft built up from steel rod & brass? 

Mike N


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## b.lindsey (Nov 23, 2008)

Jim,
Its just the 3 jaw chuck from the lathe. There is a threaded adaptor that fits into the mill's T-slots that the chuck screws onto. I lined up one flat with a dial indicator, centered the bore with the mill spindle and then stepped off to drill the holes. One think I will say for Sherline is that they have a LOT of very useful accessories that allow transferring work from lathe to mill without having to rechuck the workpiece.

Regards.
Bill


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## b.lindsey (Nov 23, 2008)

Mike,
Yes, the crankshaft is built up and loctited together since there will be very little stress on it. Jerry calls for Stainless and Drill Rod but I chose to use brass for the disks and drill rod for the shafts. The fan blades and hub will be brass also and I liked the contrast with the otherwise drab gray of the aluminum and steel main body. 

Bill


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## T70MkIII (Nov 24, 2008)

A very nice project! I've been thinking of building one of these as my 1st IC engine.


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## mklotz (Nov 24, 2008)

Beautiful work, Bill. I must build one of these for my lectures to the school kids. In those presentations I tell them about the fact that the British, during the Indian Raj, having no electricity, used these fans to cool themselves. For some reason this idea seems to intrigue them greatly. Perhaps it's because it helps them to relate the rather abstract idea of a heat engine to the more approachable idea of doing something genuinely useful. Having one to show them would be a great teaching aid.

One thing bothers me. In all the designs I've seen, including pictures of the ones sold commercially when they were actually used, the hot end is always directly under the fan. This means that all the waste heat rises into the fan air stream and thus is blown about along with whatever cool air is moved. While this makes for a more compact (and probably more stable) design, it seems rather inefficient from a cooling point of view.

A horizontal design with the hot end off to the side, out of the fan air stream would seem to do a better job of providing a cool breeze. Perhaps it doesn't matter. Maybe all they wanted to do was circulate air and didn't care about the waste heat which would be vented to the room regardless of the engine design.


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## b.lindsey (Nov 24, 2008)

Your point is well taken Marv, I can't say I have ever seen one with the hot cap anywhere but on the bottom. Of course even if it were on the side the waste heat would still get in the airstream of the fan I suspect. I definitely agree with the usefulness as an instructional aid. One of the thermodynamics professors saw the finned displacer body a week or so ago and asked what it was. I told him it was a new HVAC trainer for the thermo lab :big: Then again I may try to somehow integrate it into the machine shop practices lecture I teach in the Spring.

Regards,
Bill


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## rake60 (Nov 24, 2008)

Bill your web site *Workbench Miniatures* was in my bookmarked in my favorites folder long before 
you joined us here. You never know if the person behind the site is a craftsman or just a salesman. 
I am very pleased see that my suspicions were correct on your site.

Beautiful craftsmanship! :bow:

Rick


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## shred (Nov 24, 2008)

mklotz  said:
			
		

> One thing bothers me. In all the designs I've seen, including pictures of the ones sold commercially when they were actually used, the hot end is always directly under the fan. This means that all the waste heat rises into the fan air stream and thus is blown about along with whatever cool air is moved. While this makes for a more compact (and probably more stable) design, it seems rather inefficient from a cooling point of view.
> 
> A horizontal design with the hot end off to the side, out of the fan air stream would seem to do a better job of providing a cool breeze. Perhaps it doesn't matter. Maybe all they wanted to do was circulate air and didn't care about the waste heat which would be vented to the room regardless of the engine design.


IIRC at least some of the originals had chimneys such that the waste heat exited above the airstream. Beyond that, I've also wondered about why the heat source is directly below the fan blades.

I suspect in the sorts of places these were popular, the heat and humidity were already such that an extra candlepower or two didn't affect anything.


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## b.lindsey (Nov 25, 2008)

Thanks to all for the nice comments. I hope someday to attain that title of craftsman, but until then there is at least a dedicated hobbyist behind the website and I hope to grow the site more over the next year or so and beyond. 

Rick...thank you for your kind words as well (and for the plug too  ).

Probably won't get much done on the sterling fan until the weekend as we are off to Atlanta for the holiday, but returning Saturday early enough to get some shop time in I hope. Its getting close enough now to really want to see it run myself.

Bill


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## b.lindsey (Dec 7, 2008)

Progress report on the sterling fan...those 13 degree holes in the base and upper leg support were finally done with the help of a new angle plate which arrived this week. All in all it worked nicely with the set-up shown.







Then some of the very small linkage parts were made for the displacer piston and power piston. Most of these were only .125" diameter at the largest section and a couple required remaking the second or third time until I was happy with the results. The graphite piston is also shown with its retainer and rod end fitting attached












The last picture shows the legs installed temporarily in the base just to get an idea of the overall height. Note the power cylinder was removed in this picture as it was being used to properly fit the graphite piston.






Now on to the fan blade hub and blade assembly, the alcohol burner, and one more rod end bearing for the power piston crankdisk. 

Regards,
Bill


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## b.lindsey (Dec 10, 2008)

A little more progress has been made....power piston and linkage finished and installed and a start on the alcohol burner (aka door knob). All that remains now is the fan blade/hub assembly to finish and a cap and wick tube for the burner and it will be ready for a first attempt at running.











Bill


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## rleete (Dec 10, 2008)

Can you tell me how you made that burner? Was it hogged out of a solid piece? How do you get the inside and outside profiles to match up?


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## b.lindsey (Dec 10, 2008)

rleete,

It is quite simply a dummy brass doorknob that has been cut down and stripped of its lacquer finish. I will make a brass cap to fit down in the hole and a smaller brass tube extending vertically in this case to hold a wick. For $5.97 at the local home store, its a lot easier than trying to make one from solid brass. The idea isn't original...I fist saw it used in Philip Duclos's fire Eater engine.

Bill


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## rleete (Dec 10, 2008)

Well, I like the idea of using existing things in innovative ways, but I was hoping there was a simple technique.

I'd like to make a shape similar to that, but elongated (think champagne flute). My first attempt ended up cutting through the wall, and destroying the part in the process.


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## ksouers (Dec 10, 2008)

rleete,
The technique you are looking for is called metal spinning. Taking thin sheets of copper, brass or aluminum and forming them over a shaped mandrel while spinning it on a lathe.

Try this web site: http://metalspinningworkshop.com/

It's a very common technique used to make musical instruments, lamps and custom auto parts.


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## b.lindsey (Dec 14, 2008)

Well it is finished other than a few cosmetic things I may still do. Tried running it yesterday afternoon with no success. There was no binding of any sort and I have worked enough with sterlings now that I suspected the power piston wasn't sealing well enough so out to the garage to make another on. Amazing what a difference a few .0001" can have on these engines, but sure enough that was the problem. Another try at running it and it came to life...just needed some running to wear the new power piston and cylinder together. It probably has a good hour or so of run time on it now and I am pleased with the smoothness. 

Anyway, here are a few finished pictures, and though I have some committments until mid-afternoon, I wil try to post a video later this afternoon or evening. 
















Stay tuned 

Bill


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## kustomkb (Dec 14, 2008)

What a little beauty!


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## Metal Mickey (Dec 14, 2008)

Excellent work! Looking forward to the video now.........


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## b.lindsey (Dec 14, 2008)

Here's the video. If it seems a bit noisy its because it is sitting on the computer desk and it resonates through the desktop and the empty space beneath. I thought the paper might isolate it better but some press on rubber feet on the bottom of the base should help considerably. If I lift it up off the desk while running it barely makes a sound at all. At the end of the video you can hear me blow out the flame as it coasts to a stop. Interesting to note though that even once the blades stop, the engine backs up a quarter to a half revolution apparently in an effort to seek the lowest volume of air captured within the power and displacer cylinders. It even does this when stone cold so i guess the power piston must be sealing pretty well.

Thanks to all who followed the build !!

Bill


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## chuck foster (Dec 14, 2008)

very nice build  8) :bow: :bow:

chuck


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## Brass_Machine (Dec 14, 2008)

Pretty cool Bill!

I showed it to SWMBO... I quote her "Hey, that's one of those things. Desk top sized! I want one."

So there ya go. I forgot, is this one of your designs? 

Eric


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## b.lindsey (Dec 14, 2008)

Eric, this is one of Jerry Howells designs...the smaller of the two sterling fans he offers.

Bill


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## rake60 (Dec 15, 2008)

Beautiful Bill!

Rick


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## Pmcguire (Mar 8, 2019)

Looking great!! 

 I’m currently working on the Ky-Ko fan but I’m not as far along as you.


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