Fairbanks 80HP 3 cylinder model

[b.lindsey]

Thanks Chuck, I know what I was thinking incorrectly now too. For some reason I had the crankshaft and crankpin spacing at .875" rather than the .4375 it shold have been, but then I saw that 7/8" bore in the crankcase too.  Not only was my brain asleep this moring, it was dead apparently...   None the less, the principle Peter suggested and his trig were correct. I will modify my sketch accordingly so as not to pass on my own confusion to others....lol

Bill

[cfellows]

I think I've worked out the trig, Bill.  The angle of the crank throw relative to the surface of the crankcase is 30 degrees.  Since the sine of 30 degrees is .5, the vertical distance from the crankcase to the center of the connecting rod throw is 7/32.  Since the connecting rod journal is 1/4", I subtract 1/8" to get the distance to the OD of the rod journal, or 3/32".  I have some 3/32" drill rod which should make a perfect spacer. 

Are those the results you get?

Thx...
Chuck

[b.lindsey]

Yes Chuck, I went back and updated the pdf file in the previous post to show .09375" or the same 3/32" you figure. Seems that by using the crankcase a a fixture you can assure the correct spacing axially along the crankshaft at the same time. Sorry for the earlier brain freeze...lol.

Bill

[cfellows]

Yes Chuck, I went back and updated the pdf file in the previous post to show .09375" or the same 3/32" you figure. Seems that by using the crankcase a a fixture you can assure the correct spacing axially along the crankshaft at the same time. Sorry for the earlier brain freeze...lol.

Bill

Thanks, Bill.  Any post which causes me to stop and think is usually a good thing.  It's amazing how many obvious (after the fact) mistakes I can make when my brain is operating on automatic.

Now that I know how I'll finish the crankshaft, I'm going to start a few other engine parts before I finally commit it to Loctite.

Chuck

[cfellows]

The 1 5/16" 12L14 steel round I ordered for the cylinders and heads hasn't arrived yet, so, today I started on the lower crankcase.  I began with a chunk of aluminum 5 1/8" x 3" x 1 1/4" thick.  The first step was to hog out the inside.  This picture shows the part after the initial hogging.  Like the upper crankcase, I used a 1/2" high speed steel roughing end mill.  I set the depth stop on the quill to 1" then I applied moderate downward pressure on the quill with one hand while cranking the table in the Y direction back and forth 13 turns each way.  I had to pause and vacuum out chips 3 or 4 times for each full depth pass.  I completed this part of the hogging operation in about 40 minutes.



With the roughing end mill locked at full depth, I began traversing the perimeter of the opening taking about .030" at a time.  It took about another 10 - 15 minutes to work my way out to the lines.  I'm really happy with this method of hogging.  It's fast, very low stress, and the results speak for themselves.  The only downside is the rough finish left by the roughing mill, but these things are usually on the inside of the engine where no one will see them.



Here is a picture of the upper and lower crankcase together.  I still have to mill the indents on the sides of both top and bottom, but that will likely be about the last operation.  I also have to do some shaping on the ends of both the top and bottom.  Current plan is to have a 5/16" long piece extending from the ends of both crankcase halves that will form a 1 1/4" diameter boss surrounding the crankshaft.



Chuck

[Don1966]

Looking good Chuck, you are committed to getting this one going. You're making great time here and glad you got the crank throw issue resolved. Looks quiet simple once you think it out. Great work as always Chuck.

Don

[cfellows]

Looking good Chuck, you are committed to getting this one going. You're making great time here and glad you got the crank throw issue resolved. Looks quiet simple once you think it out. Great work as always Chuck.

Don

Thanks, Don.  This style engine is familiar ground for me so I expect to get it finished and running in pretty short order.  The Bessemer, on the other hand, has a lot of new twists that I need to figure out.  I will finish it eventually, or at least that is the intent.

Here is a drawing of what I'm shooting for on this engine.  The drawing is subject to change, but represents my current vision.



Chuck

[AussieJimG]

You  did that drawing  on Alibre? I think I need to lift my game. That looks really great.

Jim

[Johnmcc69]

Looking real good Chuck, going to be a real nice model.

John

[cfellows]

You  did that drawing  on Alibre? I think I need to lift my game. That looks really great.

Jim

Actually, Jim, this drawing was done in Microsoft Visio.  I do all my 2D drawings in Visio then 3D model them in Alibre, although I've usually bypassed the 3D part.  I'm going to try to follow through a little better on this project.

Looking real good Chuck, going to be a real nice model.

John

Thanks, John, I'm real pleased with it so far.

Chuck

[cfellows]

I started on the flywheels today.  I had a length of 4 1/2" diameter steel pipe that I'm cutting the flywheel rims from.



Here's the rims cut off and trued up except for the ID.



Thought I'd include a picture with the rims kind of where the flywheels will be.  I kind of like to get a feel for how these things are going to look.



I'll be making the flywheel centers from aluminum and pressing them into the steel rims.  These will be eight-spoked flywheels and I'm planning to make a video of at least part of the process.

Chuck

PS... The 12L14 for the cylinders and heads came in today.   

[vcutajar]

This I will be following for sure.  I am intrigued by how people fabricate flywheels and keep everything concentric.  looking forward to your tutorial Chuck.

Vince

[steamer]

It's coming along nice Chuck!

Dave

[zeeprogrammer]

I've been following along Chuck and enjoying it.
Like Vince, I'll be interested in the flywheel fabrication too.

[cfellows]

Thanks, Zee, Dave, Vince, for the continued support. 

We had to babysit the grand kids the past couple of days so I haven't had a lot of shop time. 

I dived into Alibre again this morning and made a preliminary attempt at a flywheel.  Doesn't look too bad, but the dimensions will need tweaking a bit.  This 3D drawing, particularly when you get into assemblies causes me major brain cramps!  Unfortunately, for me, it's too easy to fall back to Visio and 2D drawing.  I probably need to force myself to use Alibre as my only design tool.  That's the only way I'll ever get half way proficient.