Elmer's Fancy II

[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

[crueby]

Wow - looking fantastic!!   

[Krypto]

It's tough to get all the fancy curves look good in metal.  Great job!

[RReid]

That looks really perty, Eric. Nice work!

[EricB]

Thanks for the comments. I spent a couple of hours making and blending the curves on the center part of the base. This is my largest freehand turning to date. If the lighting is right it does look good.

Today I made the jig for the steam passages and drilled those. After that the body was parted from the stock, leaving about a 5/16" slug which was just barely enough.

I still want to make some decorative features on each end of the body. For the crank end it's just make and fit, for the cylinder end I'll need to turn it down first.

I don't have the tools to make the cylinder as the plan shows. It shows a blind 1/2" bore that's 2" deep. I'm not sure I can do that with my Sherline lathe even if I had the drill and reamer, and the boring head is out of the question. My current plan is the drill and ream through the rough stock on my drill press and solder a cap on the end of the cylinder, then finish the outside to size and shape.

Eric

[cnr6400]

  Great work! 

[EricB]

Fresh supplies arrived today so I got the flywheel turned. I just happened to have a mandrel from a previous build that worked without alterations.

I don't have the right size brass or the tools to make the cylinder yet. Waiting on the mail. Everything I buy online seems to get lost in St Louis.

Eric

[Admiral_dk]

Beautiful work and parts     

Per         

[EricB]

Thanks for the comment. I need to work on making my flywheels more interesting.

Today I made the crankshaft. Most of the time was on the disk of course. The radius beween the throw and the counterweight is an endmill size I don't own, so I had to get creative to make it come out close to the plan. It amazes me how much work can go into a part so small. At least it's visible when the engine gets finished.

I can make the connecting rod and finish the decorative parts of the body, but everything else will have to wait for the cylinder.

Eric

[EricB]

I found I had a piece of brass I could use for the cylinder. The piece was 1" square and 3/4" is called for so I had to cut it down.

The first setup looks kind of dicey but it was quite rigid and was so much easier than the hacksaw method. I did need to reposition the stock in the vise for last cut. The first cuts left a wedge shapped section at the bottom where the saw could not reach. All that was left was a tiny bit in the center which broke with a slight twist.

Trimming the first side was a little more difficult. The saw left a strip down the center that I could not break and I had to use a hand saw to get it free. The second side cut off without intervention.

The good part is I didn't convert all the brass to chips like I have with the aluminum parts, and the off cuts are still useable.

Now I'll see if I can bore the cylinder...

Eric

[EricB]

Not wanting to wait, I decided to bore the cylinder with whatever tools I have on hand. The goal was 1/2" dia and 2" depth.

I started with a 3/8" drill. Not the best choice for a MT0 taper tailstock but I made certain it was braced so that it could not spin. That worked but the lathe motor couldn't handle the load.

Take two, I drilled to depth with a 1/4" drill. No problem. Then went to my longest Sherline boring tool which could only reach to 1.25".

From there I went to my cheap import carbide boring bars. No joy, just chatter. Even chipped one of them. Trash.

Back to the drills, I had 3/4" more to bore so I used larger drills in steps up to the 3/8" I started with.

The last tool on my list was a 1/4" endmill. I had to make a split sleave for it to fit my boring bar holder. After that it still took a bit of trial but I finished the bore the 2.008" depth and 0.496" dia. I can live with that.

Eric