# Tesla Turbine



## Powder keg (Oct 22, 2007)

Hey Everyone, 

I've been lurking here for a couple of weeks. I like this place. 

First I'll introduce myself. I'm a full time Machinist and I love it! I have two lathes at home. A 13" X 60" LeBlond and a South Bend Junior 9" X 48". I have a Enco bench mill and a couple of welders. Ive also been building up a home foundry. The place I work just bought an older CNC mill. They have been sending me to school to learn how to run it. I've built several engines, steam and atmospheric. I've been wanting a Tesla style turbine. I love the way they sound:O). 

My next project will be some patterns that I've drawn up to build my own Tesla Turbine. I plan on using CD's for the discs and bearings from small RC cars for the shaft. I'm planing on building the patterns on the CNC mill at school. I'll post some pictures of the Patterns and the castings when I get time. 

Later, Wes


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## rake60 (Oct 22, 2007)

Welcome Wes

Rick


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## wareagle (Oct 22, 2007)

Wes, welcome to the forum.  We look forward to reading your posts!

W/E


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## Cedge (Oct 22, 2007)

Welcome aboard Wes. Have your choice of top bunks...LOL

Steve


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## lugnut (Oct 22, 2007)

Welcome Wes, I saw you handle the other day and looked at your profile,  Your from Idaho it says,  I am from Idaho (Lost River) and now in Oregon.  Looking forward to seeing your projects.  One of the great things about this forum is: you can jump in and act like you own the place and we would love it.
Welcome
Mel


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## Powder keg (Oct 24, 2007)

Thanks for the warm welcome. 

I decided to make three castings for this engine. They will consist of a main housing, a bearing cover, and an exhaust cover. I drew up the bearing cover with Mastercam. It has  gussets and the name engraved on it.  I glued up the pieces tonight. I'll machine it out of Poplar on Thursday and post some pictures. The housing Will be next. I've designed this engine it to look like it was made 100 years ago. The three gussets are S shaped like on old Flywheels. The housing will have the base cast into it. It should be a fairly easy engine to build. 

Later, Wes


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## Mcgyver (Oct 24, 2007)

sounds interesting Wes, i'm sure i'm not the only one who looks forward to the pics.  any rpm objectives?  what are you doing for bearings?


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## Powder keg (Oct 24, 2007)

I'll be happy if it just runs :lol I'm using bearings from an RC car for the spindle. They will probably go out pretty soon? I have an Idea for a magnetic coupling to run a little generator of some sort. I have some Ideas that I want to try. I also might sell some castings on Ebay?

I've been casting for 4 years or so and I'm tired of casting knick nacks and such. I have a couple of small cannons, cast from Bronze, that I have just about done. I've been away from these little engines for 8 years or so and I want to get back into building them. I can post some pictures if any are interested?

Wes


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## Bogstandard (Oct 25, 2007)

Welcome Wes,
Good to have you on board.
I too have designed and built a turbine, but a pocket edged one.
http://freeforums4u.com/viewtopic.php?t=244&mforum=homemodelengine

Ed Miles gave some very good advice about the bearings to use in that article.

I don't want to rain on your parade, but be very careful about using CD discs for your turbine. They are not of solid material but made up of layers that are very weakly 'stuck' together, and as soon as you penetrate the outer surface the metal foil inside will instantly oxidize and effectively delaminate the layers, making them very liable to shatter very quickly. To prove this, just get a sharp implement and 'cut' into the edge of a cd, you should find that it just delaminates very quickly and you will be able to peel it apart. If you are very careful you might be able to use the different layers for your rotors after they are delaminated, but they would be very thin. In all honesty I would use either metal or macrolon.
At the sort of speeds you are likely to encounter safety is of paramount importance, and we wouldn't want anyone being injured just for the lack of advice.
You will notice on my build that I replaced one of the end shields with a solid metal one, and the other end is 1/4" thick 'bullet proof' macrolon, all because of the safety issue involved with this type of 'engine'.

John


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## rake60 (Oct 25, 2007)

The _great scientific minds_ of the MythBusters  :roll:  did an episode
on CD's failing at high speeds.  Of course they intentionally damaged a few
to be sure they would fail, but in their test an undamaged CD blew apart
at 25,000RPM.  

Someone went to the trouble of posting a video of that show on YouTube
at: [ame]http://www.youtube.com/watch?v=-c35O8mnToE[/ame]

Be safe!

Rick


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## Bogstandard (Oct 25, 2007)

Rick,
I had never seen that demo, but it does tend to back up my theory about the CD being too unstable to use in this sort of engine.
My all metal turbine reaches 25K in a matter of seconds, but it does level out at around 35 to 36K because of the load of the generator (measured with an optical tacho).

John


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## mklotz (Oct 25, 2007)

I've never built a Tesla turbine but, if I were to, I wouldn't even consider using CDs.
Aside from safety considerations, I wouldn't want to put that much construction effort into something that might literally explode on its first run.

Look around for some scrap hard disk platters.  They're made of metal instead of plastic and are engineered to run at high rotational speeds.  Since nobody repairs hard disks anymore, a local computer 'repair' facility will often have a dumpster filled with them.

The ferric oxide coating probably won't do well with steam but for compressed air they should do fine.


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## shred (Oct 25, 2007)

mklotz said:
			
		

> I've never built a Tesla turbine but, if I were to, I wouldn't even consider using CDs.
> Aside from safety considerations, I wouldn't want to put that much construction effort into something that might literally explode on its first run.
> 
> Look around for some scrap hard disk platters.  They're made of metal instead of plastic and are engineered to run at high rotational speeds.  Since nobody repairs hard disks anymore, a local computer 'repair' facility will often have a dumpster filled with them.


Just be careful to verify they're aluminum platters and not glass.  Some hard drives have/had glass platters.  Ouch.  

FWIW, 10000-15000 RPM is about as fast as disks ever go, so beyond that you're in uncharted territory.  They are fantastically well made and balanced though.  Also snag the magnets while you're in there.  Very good magnets, those.


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## Powder keg (Oct 30, 2007)

OK, I'll reconsider the CD's. I think I have some thin aluminum lying around here somewhere?

I re-drew some of the parts on my cap last Thursday and re-did the tool paths. I'll be able to machine it tonight. There are 57,000 tool paths on this cap:O) I found out that I could add draft to my drawing. I added 4 degrees to all the vertical surfaces on my drawing. I also drew up the main housing. Hopefully I'll have some pictures soon. 

Later, Wes


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## rake60 (Oct 30, 2007)

We're looking forward to progress pics Wes.

Rick


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## Powder keg (Oct 31, 2007)

I finally got to machine the cap for my Tesla Turbine  Here is a series of photos showing what happened :shock:  This is the machine I used. It is a CNC router. I used double sided tape to hold it down while it was being machined. 






Here is the start of many passed. There were 57,000 lines of code in the program to machine this. 





A little deeper now. You can start to see the gussets forming. 





Here all the roughing passes are finished. You can see how much nicer the finish passes are making things look. 





The finish passes are done here. I changed the tool and am ready to engrave the name into the engine cover. 





I made three passes to get rid of the "fuzz".





Here is what it looked like when the machine work was done. I think It turned out great!!!  





Now lets see if a video will work?




I'll try and cast this soon. I want to see how it turns out. 

Later, Wes


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## Powder keg (Oct 31, 2007)

Whoa! That was a lot of pictures :lol:  I think I need some suggestions on cutting out some thin aluminum discs? I'm thinking of doing it on my mill with my rotary table? I have also thought about some clamping discs on my lathe? I'll have to think about it. 

Later, Wes


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## mklotz (Oct 31, 2007)

Double sided carpet tape on a sacrificial plate bolted to your faceplate.  A similar approach will work on the RT as well.

Superglue is a possibility too.  Soak with acetone to release or use gentle heat.  A hot air gun works well.


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## Powder keg (Oct 31, 2007)

I'll try the Superglue trick. I'd worry about bending the discs trying to get them free of the tape. 

I have the case drawn up and will finish it and the toolpaths Thursday. I'll take plenty of pictures when I get it done. I think this will be a fun engine. 

Later, Wes


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## Bogstandard (Nov 1, 2007)

Have a look at my post here
http://freeforums4u.com/viewtopic.php?t=228&mforum=homemodelengine
Look at the bit about friction turning and instead of drilling the centre, make up a turned slug with a centre and use that between the rotating centre and the discs. Put two very small bits of double sided tape ( about 1/4" square) on opposing sides of the discs, out towards the edge, between each one. Make a lot more than you need, maybe 20%. 
Once you have the pack to size you should be able to hold them in your outside jaws to put the centre hole thru.
To get them apart, just drop them into white spirits (don't know the american term), the spirits used for cleaning brushes after painting glosswork around the house. They should just fall apart.

John


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## Powder keg (Nov 2, 2007)

I cast some covers yesterday. They turned out great!!! I'll post some pictures soon. 

I'm drawing the case up with Mastercam. I was having troubles getting the base like I want it, so I didn't get to machine it yet. I stumped the instructor so he's going to look into it for me. It will look pretty nice when done though. 

I'm thinking about making the exhaust cover out of Plexyglass? I think it would look neat to be able to see the discs spinning.


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## Powder keg (Nov 2, 2007)

Here are a couple pictures of those bearing covers that I cast. I did a bronze one also. They look a little rough because the of the finish I used on my pattern. They will clean up fine with some steel wool. I finished it with tung oil and the sand wanted to stick to it for some reason? I'll go over it with some polyurethane and make the surface nice and slick. It will come out of the sand better then. 












I cant wait to get the rest of the bits for this engine together.


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## Powder keg (Jan 23, 2008)

During the first semester of school, I made the cap for my Tesla turbine. We had trouble getting the drawing sorted out on the case of the engine. Tuesday I finished the drawing and I'll try and machine the cast patterns during the next couple of classes. The drawing turned out really good:O)

Wes


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## zeusrekning (Jan 23, 2008)

Wes, what software did you use to program that.


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## Powder keg (Jan 23, 2008)

We are learning Mastercam. It is a great Program! Lots of stuff to know though. The base for my turbine even stumped the instructor for a bit:O) But we got it figured out.

Wes


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## Powder keg (Feb 8, 2008)

Here are a couple of quick pictures. The first is just starting the cuts. The second is the finish pass. The bottom was a bit choppy. I could have narrowed the step over a bit to fix it, but I'll just sand it a bit:O)










I'll get some more pictures later.

Wes


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## Brass_Machine (Feb 8, 2008)

This is a pattern to be cast? Just out of curiosity, why not CNC it in the metal you want to avoid the extra step of casting? Or is this a just because you can endeavor?

Eric


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## Powder keg (Feb 8, 2008)

Yes, its a pattern. I really like the way cast parts look. Casting metal is also another hobby of mine. I also plan on selling a few kits to help finance my hobby's:O) That is why i did so many flywheel patterns last semester. 

Wes


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## Brass_Machine (Feb 8, 2008)

Powder keg  said:
			
		

> Yes, its a pattern. I really like the way cast parts look. Casting metal is also another hobby of mine. I also plan on selling a few kits to help finance my hobby's:O) That is why i did so many flywheel patterns last semester.
> 
> Wes



Very good answer. I completely understand about financing the hobby...

Eric


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## Powder keg (Feb 9, 2008)

Here are the two half's together. I'll pin them and finish sand them soon. I think this will work pretty good. The base is a little fatter than I wanted. I might file it down and shape it a bit?






Making these patterns on the CNC's has been fun. It is neat to be able to draw something up and have it appear on the mill table out of a chunk of stock. 

Later, Wes


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## Powder keg (Mar 9, 2008)

I have the two half's of the housing pinned together now. I'll start filing and sanding this pattern down. I think I'm going to streamline the base a bit? My back yard is dry now, so I can start casting again. Yahoo!!!!

On Saturday a friend and I went to Prove, Utah to visit Birk and Guy Francis. We had a great time!!! During our visit, Birk went over riveting with me. I think I am going to try and rivet the discs together. This is supposed to make the discs more stable. It was easier than I thought it would be) 

Later, Wes


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## Brass_Machine (Mar 9, 2008)

Very cool.

I wish I was close enough to visit with Birk as well... I am envious of you and Guy.

Can't wait to see the turbine. Take lots of pics of the casting please


Eric


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## Powder keg (Mar 9, 2008)

I'm afraid that if we were closer Birk would get tired of me soon. We had a 3 hour drive.

I'll take plenty of pictures)


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## Florian (Apr 26, 2008)

Hi

The tesla turbine is also a theme in another, german discussion board. 
_And_ there was a guy who lasered some disks. And as he thougt other would also want to build a tesla turbine, he lasered in the end something about 7 sets for a tesla turbine. The disks are made of 1.4305 so they are able to withstand up to 60'000 rpm. (He calculated it...). The point is, i also ordered one set. And i already made some 3-D CAD drawings:













And here the discs with spacers and some raw material for the spindle and the disc retainer.






Florian


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## BobWarfield (Apr 26, 2008)

Very interesting!

Given the desirability of laser cut disks, this would be another design particularly well suited to a Team Build format.

Cheers,

BW


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## Florian (Apr 26, 2008)

BobWarfield  said:
			
		

> Very interesting!
> 
> Given the desirability of laser cut disks, this would be another design particularly well suited to a Team Build format.
> 
> ...



Of course. 

I have also Plans from the guy who organized these discs. (However, i am not going to build it from these plans...)
If anyone here wants them (just for their own use!!), i can send a .pdf with the plans and calculations (german language...). 

Florian


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## dreeves (Dec 16, 2008)

I built the tesla turbine that was in the homeshop machinest a few years ago. It is a fast and smooth runner with the ball bearings. I built mine 1/2 the side in the book.


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