Stirling engine build

[Longboy]

Hi Mitch,

For that power piston / cylinder good combination to be used in a stirling-engine are cast-iron, stainless steel together with bronze.
I would not use aluminum for that power piston at all, it's way to soft, it will jam.
Coefficient of expansion is a very important issue here...!


Chris

An aluminum piston in this application will be fine. Dave

 

[Mitchg07261995]

An aluminum piston in this application will be fine. Dave

thats what i was thinking thanks Dave!

 

[Mitchg07261995]

.... today sucked, for some reason my teacher was mad at me for something so he made me clean every machine in the shop, and organize all the drill bits so i literally got no work done today maybe monday will be better

 

[aarggh]

Don't take it to heart Mitch, quite possibly he had somethng crummy happen and you were just unfortunately the one to bear the brunt!

cheers, Ian

 

[Mitchg07261995]

Don't take it to heart Mitch, quite possibly he had somethng crummy happen and you were just unfortunately the one to bear the brunt!

cheers, Ian

thanks for that Ian, but when I went in the class room he had written "Mitch cleans all day" on the board lol
i know monday will be better
we have a cool tiny mill like the ones from sherline that i was talking to him about today, he says that know one has used it in the class and that no one has even turned it on... im thinking of asking if i can buy it from the class? then i can take some of my work home and get some more time in what should I offer? ill have to look at it more closely but it looks really clean, has some dust from sitting so long, and does not have a vice? it does have a plastic part in it now but it is mounted with screws and the machine does not appear to have a endmill, or collet with it

 

[Mitchg07261995]

well, today I plan to make the main layout for the base of my engine which measures 6''x 4 and 5/8'' wide. I dont have the plans for the engine as I forgot them at my house and I am at my grandmothers house :rant:
I already have the aluminum plate for the base with the lines marked into the face with the blue layout fluid, I plan to use one of our flycutters at about 3000 rpm (what I have been using, and it has worked out for me) with some wd40 as a cutting fluid
pictures to follow tonight

 

[franscubitt]

Hi Mitch
Did you make an offer on the milling machine? It sound like you are doing well, we need pictures please
cheers Frans

 

[Mitchg07261995]

Hi Mitch
Did you make an offer on the milling machine? It sound like you are doing well, we need pictures please
cheers Frans

Hey Frans! I made an offer on the mill which is indeed a Sherline, my teacher said sorry but it is not for sale But hey that is fine with me
I did not make progress on the mounting plate today, I started but fudged it up so it sits in the scrap pile now :'(
Hopefully better progress tomorrow, I have 8 weeks left in this class before the end of the school year, maybe it is time for me to come in on friday's which is my off day from this class

 

[Mitchg07261995]

Today I went back to the lathe and started work on the displacer cylinder. It is being made out of 361 stainless steel
not close to being done yet but, any progress is good

now the part it self

and the other kids in my class were cutting steel on the band saw for the base which is .250 thick, so i think ill just leave the thickness alone and make the base 6'' long and 4''5/8'' wide

 

[Mitchg07261995]

ok, so far i have 6 parts complete out of 24...
flywheel is almost complete, i have 3 other parts that could be finished in 4 hours (length of my class) i think im gonna buy a small alcohol burner so that i dont have to make one, the base plate should take a couple days, i hope to have the displacer cylinder complete in a couple weeks

 

[Mitchg07261995]

got some more work done on the displacer cylinder today, i now have 8 hours into this one part! mainly because of freakishly slow feed rates. Lathe is in back gear turning 55rpm the whole time and the feed rate is .0007'' per rev

part is about .600 to long on the side with the flange, I am ready to part off the extra stock, face that end down to a finished length of 4.000'' then I can drill the wholes in the cylinder, Im planning on starting with the whole in the side that way i prevent taking the part out of round if i do that after boring the i.d. for the piston
I.D is supposed to be 1 and 3/16''
this is going great

 

[Hopper]

Mitch,
What is the diameter of the power piston and what is its stroke?
And what is the stroke on the displacer piston?

I want to build a similar engine so would like to get the bore/stroke ratio right for each cylinder unit.

Thanks

 

[Mitchg07261995]

Mitch,
What is the diameter of the power piston and what is its stroke?
And what is the stroke on the displacer piston?

I want to build a similar engine so would like to get the bore/stroke ratio right for each cylinder unit.

Thanks

your in luck Hopper. i took all the parts i have made, the stock for parts to be made and the plans home with me again today.

Diameter of power piston: 11/16''
I cant find the front page so i cant say what the stroke of the pistons are
diameter of displacer piston is =1.125"
I.D of discplacer cylinder is 1.1875
sorry that i cant remember the stroke, ill see if someone in my class has the first page tomorrow and ill get back to you

 

[aarggh]

You're doing a great job on all this Mitch! I'm enjoying watching your progress mate. It's a shame the teacher doesn't want to let go the lathe, you could always guilt him into it by using your youth to your advantage, just occasionally pass by him and the lathe with a pathetically wistful expression, glancing at the lathe, and don't forget to sigh every now and then! In all seriousness, if there's any possibility of buying any tools or machines from there, don't feel at all awkward about holding back in letting him know you really, really, really want it. Your display of genuine keenness might be the tipping point.

cheers, Ian

 

[Mitchg07261995]

thanks for that aarggh, i am really enjoying this build and cant wait to work on the displacer cylinder tomorrow. After tomorrow its spring break for me so i wont be able to make any progress for a whole week, lol this is when i wish i had my own machines at home so i could work when i want and as long as i want. Ill keep your tips in mind my teacher bought another cnc lathe for out class with some of our cash, i believe it is a haas as the other cnc's we have are haas machines, we have a mini mill, 2 vf1's and a haas vf4.
Ill learn the cnc stuff next year, so right now all the 1st year students are working on southbend lathes, and good ol' bridgeport mills. We have a huge lathe in out class that I want to work on, it is a american pacemaker, i cant remember the size of it i believe that its 18x72? ill have to look again, but the thing will do 15rpm and faster

 

[Mitchg07261995]

the displacer cylinder is almost done! put another 4hours of work into it today, got the over length down to 4.0015 and it is supposed to be 4.000. I know that if i try to fix it, ill accidently make it shorter than 4'' so im leaving it.
As to Hoppers question, i got the paper that tells the stroke for the power and displacer cylinder
Power cylinder: 1''
Displacer cylinder: 1.250''
What else i did on the displacer cylinder: drilled the 3/16'' whole in the center of the cylinder 2'' down from the face, and started drilling the i.d, i got the first drill done which was 11/16 in diam. i plan to use a 1'' diam drill next, then finish it to 1.1875'' with the boring bar

well thats all for the next week because of spring break

 

[franscubitt]

Wow Mitch looking very nice, hope u have nice spring break.
Whats the weather like where you are?
cheers Frans

 

[Mitchg07261995]

Wow Mitch looking very nice, hope u have nice spring break.
Whats the weather like where you are?
cheers Frans

Thanks Frans, i might be going to ride dirtbikes next week with my uncle so spring break will be fun
As to the weather, we got 1.5 feet of snow over night and its still snowing

 

[Mitchg07261995]

well... since i cant work on the engine due to spring break i went to the antique store tonight and found a fuel burner for $4.25 tested it and it works great and is just short enough for the displacer cylinder to go over it when mounted to the standard
I have been thinking, 6 weeks left of the class their for this year when i get back next week, and the last two weeks will be spent in the computer lab, maybe i should show up for the morning and afternoon classes on tuesday so i can get more work done on this engine and have it running by the end of the school year. I have also been thinking about how i could save some time building this... Im thinking that for the engine stand ill keep it ats its raw stock thickness of .250'', width of 6'' and trim down the front and back so that it has an over all length of 7''. It is at 7.125" currently, so all i have to do is trim the ends on the mill down to 7'' drill all the mounting wholes (10 of them) and be done
what do you guys think?

 

[Hopper]

your in luck Hopper. i took all the parts i have made, the stock for parts to be made and the plans home with me again today.

Diameter of power piston: 11/16''
I cant find the front page so i cant say what the stroke of the pistons are
diameter of displacer piston is =1.125"
I.D of discplacer cylinder is 1.1875
sorry that i cant remember the stroke, ill see if someone in my class has the first page tomorrow and ill get back to you

Thanks Mitch. I think the stroke is probably about one inch, ie crank offset of half inch?