Farm Boy Milestones

[Geartooth]

I finished making the crankshaft for Jerry Howell "Farm Boy" engine today. Do any of you still get a thrill when you first spin your crankshaft.

 

[canadianhorsepower]

were are all the other pictures
nice work

 

[Geartooth]

I started this build by making the parts for the frame. Here is how they look.

 

[Brian Rupnow]

Crankshafts are always a thrill!---And it's much, much better when it's a good thrill. I have a couple of the other kind of thrill in my 'Oh Poop' bin.

 

[RichD]

Farm Boy is looking good. The pictures of the engine plans also look nice and clean.

I was trying to figure out how you got those square corners in the crankcase cavity, then I noticed the two halves were joined in the middle. Nice looking machine work.
Rich

 

[Geartooth]

When first looking at Jerry Howell’s plans for the Farm Boy engine, two items caused me some concern. I had never turned a crankshaft from the solid or cut working gears. Since I did not want to spend the money on store bought gear cutters, I spent the better part of a workday hand sharpening a double ended fly cutter tool bit to get the required profiles of the gear teeth for the timing gears for the Farm Boy engine. I used a spread sheet that calls out the button diameter and spacing to cut a form cutter. I took those dimensions to follow when grinding my fly cutter tool bit.

I had previously turned the gear blanks along with two test blanks in aluminum. After a little misunderstanding with my dividing head, I cut the two gears. The picture of the aluminum gears shows why I was lucky to have the test blanks.

Call it beginners luck or paying attention to the numbers, but both the crankshaft and my gears came out fantastic. The crank runs true and the gears mesh smoothly with only the slightest perceptible backlash.

 

[RichD]

Excellent work!

 

[gg89220]

les pieces sont parfaite ,bravo

 

[Lathejack]

That's a very nicely made crankshaft, I like the way the webs have been left as cast, just as on full size engines.

I also recently machined a crank from a solid casting for the first time, it's for the 1/4 scale Red Wing engine, and thankfully it turned out ok at the first attempt. I machined the webs as well, but after looking at yours I now wish I hadn't.

I am impressed at your first attempt at cutting gears. I did not make the gears for my engine, although I have all the equipment to do so. I must make the effort to set it all up and have a proper go.

I did once cut a single gear in the lathe, using the carraige travel to cut the teeth with a single point cutter and with the gear blank on a shaft mounted in the chuck using another gear as a simple dividing device. It took a long time and came out almost but not quite usable.

 

[JLeatherman]

That's a very nicely made crankshaft, I like the way the webs have been left as cast, just as on full size engines.

Was that crank left "as cast" or did you roughen those surfaces after machining to resemble cast? What material did you choose for the crank?

 

[Lathejack]

I assumed the crank was from a casting, maybe it was made from steel flat bar and that's the surface finish that remains on the webs.

I reread the posts more carefully and it does actually say "cut from the solid" although the surface finish left is a little unusual for steel flat bar.

 

[Swifty]

Could be made from hot rolled, hence the scaly finish.

Paul.

 

[RichD]

Geartooth,
I've noticed how your photographs look so clear while mine come out terrible. I'm still using one of our older 2.3mp cameras. I guess I'll have try one of our newer cameras.

I'm so stubborn about upgrades and new gizmos.

Rich

 

[Geartooth]

To answer the questions brought up:
The crank was made from a piece of hot roll steel from Speedy Metals. They did not give it any particular identification. The remaining webs have the scale from the raw bar. I treated the machined portions of the webs with Eastwoods Metal Black to simulate the raw look.

I can not hold a camera still so I use a tripod and set the camera to timer mode. Then I take several shots and choose the better one.

 

[Geartooth]

I have just made and assembled the pieces that make up the fly ball weights for the Farm Boy engine. I paid close attention to the dimensions of the parts, but on Jerry Howell's plans he shows the assembled length of 1.520 and you can see mine measure 1.645. I'm hoping the drawing should of shown his dimension from the pivot centerline instead of the overall measurement.
If you do the math from the individual parts, you get a dimension more like mine. Do I change them or are they correct?

 

[Geartooth]

I thought I should finish the piston assembly, with the connecting rod, bearings, and piston. The farm Boy engine has a 1.000 bore and 1.375 stroke. Jerry Howell suggests that Babbit be used for the bearings so I cast a bar to machine into the bearings. His method is to solder the two halves together then turn the bearing and then separate them. I chose to make two identical bearings and mill away half of each one. It wasn't clear to me how the wrist pin received oil untill I put the parts together.

 

[Geartooth]

Its time to update the progress on my Farm Boy engine (s/n 510). Little had been done in the Summer months of 2015. The stumbling block was obtaining the material to make the flywheels. The plans called for 6 inch diameter cast iron. I will be the first one to call myself cheap and unwilling to spend my retirement checks on a project that will no doubt only sit on a shelf. The local steel dealers never had anything like that in their scrap bins. What I did have, from a previous hobby, was a lot of lead printing type. Printing type is a hard lead compound which breaks before it will bend. I made molds from plaster of paris and poured the rough castings for my flywheels. These casting ring like a bell when struck. As cast, the wheel weighed 9 pounds each. After machining they weigh only 4 1/2 pounds each. I don't know how that compares to a cast iron version.
The last photo shows the semi finished flywheels, before detailed deburring, setting in place on the engine.
In the future, I can always make them again in cast iron.

 

[10K Pete]

Well, I'd say that was darned clever of you to substitute Linotype metal for the flywheels.
It just happens I have about 700 lbs of the stuff in the shed and I was wondering
how to make a couple of 10" flywheels!!

Thanks for the idea!!

Pete

 

[geo]

I get the same dimensions as you did you ever find out if the drawing was correct It seems to work from centreline to centre line.

 

[geo]

I have just made and assembled the pieces that make up the fly ball weights for the Farm Boy engine. I paid close attention to the dimensions of the parts, but on Jerry Howell's plans he shows the assembled length of 1.520 and you can see mine measure 1.645. I'm hoping the drawing should of shown his dimension from the pivot centerline instead of the overall measurement.
If you do the math from the individual parts, you get a dimension more like mine. Do I change them or are they correct?

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