SAM

[petertha]

Nice build pictures. I would like to know more details about:

- post #5 re your lapping procedure. What is the mandrel made of, type of compounds used? About how much material is removed from this stage from the preceeding boring/reaming?

- post #10 re crankshaft details. Is the crankpin & counterweights & main crankshaft body all press fit together & if so, any retention compound like locktite used? How do the counterweights get aligned & stay that way?

 

[yogi]

petertha,

The lap is made out of aluminum. We took a round piece of stock and made a cut to make it expandable. It is a simple lap, and it worked well for us. We will experiment with different materials in future projects, and see what we can learn...
As for the lapping compound, I have to admit, I'm not quite sure what we used... After our Grandpa passed, we inherited his tools. In one of his toolboxes, we found tubes of lapping compound. We don't know the grit, we just started with the most coarse on and went from there, til we had a surface to our satisfaction.
The total material removed, during the lapping process, was about 0.02mm in diameter.
Also, the cylinder liner is turned to a very smooth finish before lapping, rather then reaming. Unless you have a good reamer that produces a good finish, I would not recommend that.
The finished dimension of the cylinder isn't that important, the important part is the piston/cylinder fit.

The crank pin has a press fit in the crank discs, while the main shaft is secured with set screws. This procedure can yield a very true running crank shaft. the important part is to make the two holes in the discs perfectly parallel. I did that using a boring head on the mill, and machining both discs at the same time. I'm suggesting 0.02-0.03mm press fit.
Pressing the pin into the discs, I used a piece of stock the same diameter as the shaft, to align the two discs. Use a good vice with straight jaws to press it together, that will help ensure everything is straight.

See attached drawing.

I hope that answers your questions.

Yogi

View attachment Crank Shaft Assembly.pdf

 

[yogi]

IT'S ALIVE!!!!

After just little more than a week of serious machining, we are proud to announce SAM's first pop! ;D ;D ;D

Enjoy!

[ame]http://www.youtube.com/watch?v=JoGc7Io-qXc[/ame]

 

[metalmad]

Congrats u guys
us old guys just can not stand that kind of pace nowdays :big:
Pete

 

[petertha]

petertha, The lap is made out of aluminum. We took a round piece of stock and made a cut to make it expandable. Yogi

Very useful, thanks!

It kind of looks like a set screw or fastener on the side. Does that act to expand the mandrel against the slit cut? Or is that just to secure it on the shaft?

Do you machine in any slight taper to the aluminum lap cylinder barrel, or strive to keep it the same OD throughout?

What is the material of the steel cyclinder liner?

 

[kcmillin]

Well Done Yogi! I am amazed at the speed in which you completed this engine. It sounds great, and runs smooth, and the fact you made it with tools from your Grampa, you must be very proud.

Kel

 

[yogi]

petertha,

The set screw on the lap is to expand it. There is no taper at all, it is as cylindrical as possible.

The cylinder liner and the piston are both made out of cast iron.


Yogi

 

[Speedy]

has a wonderful sound.

 

[yogi]

Hello everyone,

The work on SAM continues...
We are now working on the governor mechanism, and to put the finishing touches on the engines...
The plan is to have it run in hit & miss "mode" by tomorrow...

Here a couple pictures of the flywheel being machined and the finished product. The flywheels ended up bit bigger than initially planed. The diameter is now 120mm... 8)

Enjoy!

 

[yogi]

The governor is finished and working...

The only thing left to do, is a few bits and pieces (like the crank case plugs) and we'll be finished.

 

[yogi]

The SAM twins...

Enjoy!

[ame]http://www.youtube.com/watch?v=CqjVbe5BkX0[/ame]

[ame]http://www.youtube.com/watch?v=NQSuSw0MnkA[/ame]

 

[yogi]

Does anybody even care???

I guess I can save myself the trouble of posting anything as there seems to be no interest in our project!

This forum always seemed very open and welcoming to all people and skill levels. I must have missed the mark...

There are not going to be any future posts, my leave is over and I'll be back in Afghanistan come Monday.

Best Regards,
Yogi

 

[dsquire]

Does anybody even care???

I guess I can save myself the trouble of posting anything as there seems to be no interest in our project!

This forum always seemed very open and welcoming to all people and skill levels. I must have missed the mark...

There are not going to be any future posts, my leave is over and I'll be back in Afghanistan come Monday.

Best Regards,
Yogi

Yogi

Oh yes we care. 1450 people have stopped by to read your posts. 25 people have watched the one video and 30 people have watched the other video. Sometimes people are watching but just not posting. There is certainly nothing wrong with your skill level. It is right up there with the best of them and you have every reason to be proud of the 2 SAM engines that you have made. :bow: :bow:

I'm sorry that your leave is over so soon. Thanks for what you are doing in Afghanistan. Be safe and we look forward to many more posts from you in the future when you are able. :bow:

Cheers

Don

 

[dmac]

Hi Yogi,

I think your work is fantastic. A nice running engine.

Good luck in Afghanistan mate.

Dave.

 

[Leucetius]

For me it's a time issue Your video post came at 30min past midnight (germany).

I like your twins really much. The outline of your cylinder inspires me for my 1cyl 4cycle i'm poking in my head.
Congratulations!

P.S.: and kudos for your speed. you were FAST

 

[dalem9]

I am glad to see someone else has a bench that looks like mine . Great engine . Thanks for your service .My step son is over there Stay safe Dale

 

[steamer]

I've been traveling and working long hours Yogi. Sorry Thankyou for your service , and please be safe...

And do post again!

Dave

 

[steamer]

Part of the problem Yogi is there are so many great builds. We like to read things and understand...and interact. That takes time.....it's not a slight I can assure you.

Dave

 

[moconnor]

Hello Yogi,

You and your brother are very talented and have built two beautiful engines. Your being on leave explains the torrid pace of the build. Great planning and execution to pull this off in such a short period of time.

I hope you reconsider about posting in the future. Your work is an inspiration to many and I certainly hope to see more of it in the future. Don't get discouraged about the lack of comments, the silent majority (myself included) appreciate the effort that it takes to document and post your work.

Be safe in Afghanistan. Thank you for your service. My son is a US Marine and has been there. I think I aged a year for every month he has spent over there. Will look forward to your next project. Take care.

Kind regards,
Mike

 

[ozzie46]

Thanks for your service.

I have enjoyed your build and as far as my not posting on it .

No excuse ! I should have and will try to do better in the future.

Be safe and come home soon.

Ron