Fairbanks 80HP 3 Cylinder Model

[FannBlade]

I dove into the rotate boss function of Alibre tonight and managed a respectable drawing of the cylinder, curves and all. I would call it a rotational extrusion. See the attachment for a 3D representation.

Chuck

Nice job!
I'm still fumbling my way through Alibre...your miles ahead of me.

 

[cfellows]

Thanks for the continuing interest. As someone suggested, modelling a real project is probably the fastest way to learn about 3D CAD. I have requested a quote from Alibre on upgrading to GeoMagic Pro. Don't know that I really need it, but it does have some nice features.

I spent some time working on the upper crankcase half today. I'm beginning do some final shaping.

Chuck

 

[cfellows]

Managed to get 6 or 7 hours in the shop today. I Continued work on shaping the crankcase halves and except for some repair work, they are close to finished.

Started today with the bottom crankcase half. Here, I'm using a 1.25" indexable face mill to remove part of the sides and create the bottom flange...

Next, I shaped the ends using a 1/4" end mill. This particular end mill creates a small chamfer at the bottom. I'm departing from the original Fairbanks a bit here. I think it looks better for the boss on the ends to extend all the way down.

This picture shows the finished bottom half with the unfinished top half sitting on it.

Now I'm starting on the top half of the crankcase, removing material to create the flange which allows bolting the crankcase halves together.

Here's the two crankcase halves as they will look, finished, from the back.

Now I'm starting work on forming the raised frames for the crankcase access ports on the front. I hadn't originally planned to add this detail, but in the end thought it would greatly improve the looks.

Heres a series of pictures of the finished crankcase halves. I need to do some repair work on the bottoms of two of the access port holes where I fed the table a little too far. I think some JB Weld and a file will fix it, since the crankcase will be painted when finished.

Chuck

 

[aonemarine]

Now its really really looking good. Figure out how to do the crank yet? I was thinking of making 3 supports with bolt on caps, split at different heights, then drill all three with the required crankshaft degrees. The could be bolted down to a plate, sit the crank in place, bolt down the caps and solder it up.

 

[Philjoe5]

Nice work Chuck. Excellent photo documentation that is appreciated.

Cheers,
Phil

 

[RManley]

This model is going to look amazing when done! It's builds like this that make me want to start a new project, I then remember that I have at least 6 on the go and that my new years resolution was to not start anything new

Watching with great interest

Rob.

 

[Lawijt]

It looks great Chuck...Really by the "bing" by the "boom" hahaha. The pics are very good for a novice like me. So I see how you fix the workpieces on the lathe & the mill.
Keep posting the fixtures please. I learn a lot from them.

Regards

Barry

 

[johnmcc69]

Looking great Chuck, great pics & write up. I can't wait to see this finished, but am really enjoying the journey getting there.
Great job with the CAD modeling, you're getting there. I look forward to seeing finished drawings of this.

Great build!!

John

 

[cfellows]

Thanks, everybody, for the kind words. I appreciate the comments, suggestions, and support.

I got started on the heads today. They are being made from 1 5/16" diameter x 1 1/8" long 12L14 rounds. While they aren't complicated, there are numerous holes and parts that will require fairly close tolerances. For that reason, I was careful to get them all within .001" of the correct length. I also used a file to clean up all the edges since unwanted burrs can cause errors in locating. Finally, I was careful to keep the milling machine setup blown free of chips and debris while clamping things in place.

I'll start with a 2D drawing of what the head is going to look like...

I created a center hole in one of the heads to use as a datum in locating and centering the pieces in the mill. I only drilled one head and used it each time to get the part properly located. Once in place, there was no need to change the setups for the same operation on the other two heads.

I used my thumbnail on the edge of the center finder. Once I could no longer feel the edge of the split, the part is centered, or darn close!

Here, I've moved the millng table over the correct offset from the center and drilled the holes for the head bolts, using the rotary table to evenly space them around the head.

Here, I'm locating the head to bore the hole for the valve assembly. It will be 3/8" diameter by 11/16" deep, offset from the center of the head by .150"

I'm using 3/32" pins, which just happens to be the pilot hole diameter for 4-40 screws, in two of the head bolt holes to square up the head being clamped in a v-block. People who are more patient (and probably smarter) usually make fixtures to hold multiple pieces for locating and indicating. I figured I could get buy without the extra work.

And, here's the finished hole that the valve assembly will go in to...

And a couple of updated pictures of the full engine, so far...

Chuck

 

[cfellows]

One more picture for today... Attached is a PDF of the Alibre 3D drawing of the head.

Chuck

View attachment Head.pdf

 

[kilocharlie]

Thank you, Chuck, for your generous efforts at documenting and posting the project. This is a great help for my efforts at a new twist on the Alpha-type Stirling I'm designing. Your workmanship is impressive, too.

 

[cfellows]

Thanks, Charlie.

I started on the Valve cages today. I started with 5/8" cold rolled steel. Would have preferred to use brass, but didn't have any in the right size.

After turning all three down to the right length, I started the shaping by shouldering down the end that goes into the head to 3/8"

Then I drilled a thru 1/8" hole for the valve stem then enlarged the bottom end to 3/16" for the air inlet passage.

Next I reversed the piece in the 3 jaw chuck and turn down the boss which goes inside the valve spring (sorry for the blurry picture).

Here I've finished the external shaping. Still need to drill the exhaust hole and mounting screw holes which I'll do later.

And here's what it looks like in the head.

Two more to go...

Chuck

 

[cfellows]

Several smaller things done today. Finished the other two valve cages, got a good start on the pistons (cast iron), and got the timing gear blanks all shaped ready for the gear teeth. I'll do that later this evening or tomorrow. Here's a picture of most of the parts I've worked on.

Chuck

 

[cfellows]

Earlier today I cut the teeth in the timing gears. Boy, every time I use my Arduino / stepper motor powered dividing head I appreciate it more. Greatly speeds up the process and reduces the chance for error.

The larger gear is made of brass and the smaller one is 12L14 steel.

Chuck

 

[Lawijt]

Great work Chuck.

 

[Niceonetidy]

Looking good chuck, and coming along at a great speed,

Cheers,

Colin

 

[Generatorgus]

Chuck, I love those old FM engines, coming along nicely.
The gears look great.

GUS

 

[Lawijt]

Really nice Chuck. The original is Diesel engine wright?? Will yours run also on Diesel fuell??

On the backside of my eyes I see the flywheels turning already with a beautifull sound.woohoo1

 

[cfellows]

Thanks, guys, I appreciate the comments.

Gus, the original full sized engine was not a diesel... it used igniters and burned either gasoline or kerosene. My engine will be powered by compressed air but will still be 4 stroke in operation.

Here's a couple more pictures. The first one is the the crankshaft sitting in the crankcase with the Loctite hardening. The two outer lobes are supported with 3/32" brass rods sitting on top of the crankcase. I had calculated this was the height need to give me 120 degrees between throws.

And here's the crank after the Loctite has hardened. I am planning to pin the connecting rod journals to the shaft with 3/32" roll pins before I saw out the middles. The Loctite by itself is probably sufficient, but I tend to be overly cautious with these things.

Here's a shot of one of cylinder heads with the valve cage screwed in and the exhaust hole bored. The hole in the head is 3/16" and the connecting hole into the valve cage is 1/8".

I still have to drill the air inlet hole. To avoid interfering with the push rod, it will be offset from the center line and enter the valve chamber on a tangent.

Chuck

 

[cfellows]

I pinned the crankshaft throws and cut out the waste today. I guess it remains to be seen how strong it is, but it is dead-nuts straight. I think it will be fine since I have main bearing journals between each cylinder. Even if one of the joints came loose, I don't think it would bother anything.

I probably should clean it up some but I'm kind of afraid to do any more machining on it. Might just leave well enough alone.

Chuck