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Elmer's Fancy II

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EricB:
I'm working my way through Elmer's turned body wobbler engines and this is the last and the largest (I think). The body is 4 1/2" long and 1" in diameter.

Yesterday I cut the stock and commenced to rough out the shape of the body, then realized I'd cut the piece too short. Measure twice right? Rather than start again I moved the stock out of the chuck enough to give me room to work. So far, so good, but it could be interesting later.

Today was day two of turning the body. Most of the time was spent trying to make the round ball section look like a sphere. Large cuts with the compound and finishing with files. The best I could do was the elongated ball shown. After I quit for the day I figured out what I was doing wrong. I kept thinking I needed to see a full 1" wide curve of the ball, but part of that is taken up by the 1/2" circle where the sphere meets the cylinder of the body on each side. More forgotten math.

Eric

EricB:
Sort of quit for the day anyway. Did the math, narrowed the visible portion of the sphere and reshaped the rest. Still a little bit wide but looks much better. 1" rod for reference.

Eric

EricB:
Still trying to make scrap.

Yesterday I finished the shape of the engine body, even thought I got most of the dimensions right. So I moved it over to the mill for the next phase.

Making the flats went well. I like using this kind of setup because it eliminates the residual error in the table along the "Y" axis, and lets me reposition the part.

Next I had to drill some holes. I laid them out according to the dimensions and drilled/bored/reamed them. Hit all the targets too. Then I looked at their locations relative to the features they were going though. Oops! Two out of three were off center. When I shaped the ball I marked the center off of what was not a finished surface. When I finished the surface it changed the dimension but I didn't think of it at the time. For the hole at the left end I just made the feature too wide.

To fix them I found the centers of the features and enlarged the holes to bring them on center. The crank bearing (left) and the mounting post (ball) will need to be oversize now but I can hide the mistakes. I'll need to adjust the length of the connecting rod too.

Eric

EricB:
Only a couple of little parts today.

I made the bearing bushing for the crankshaft and found a piece of unknown origin steel to use as the shaft itself.

I also made the center post for the base. It's necked down to 3/8" at the bottom so that I can make the other base part according to the plan. It's tapped 10-32 from the bottom. Once I have the base complete the center post will be held into the body with some adhesive. I'll make a similar knob to fill the hole used by the dead center.

With most of the engine made from aluminum, I had to spend a good amount of time removing a bird's nest from the hose of my shop vac.

Eric

EricB:
Made the base using form tools, files and gravers. I copied the plan design for the most part. It's about 1/8" taller where the center part meets the foot. Then I made the foot so that the center part will nest into it. That way I didn't have to worry about trying to make two flat surfaces sit flush and everything stays concentric.

The plan has two mounting holes at the edge of the foot. I omitted those. I'll use the single screw under the base for that.

Eric

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