Elmer's Fancy

[EricB]

I had so much fun making Tiny that I decided to do Fancy as well.

Day one was cutting stock for the column and cylinder, and I made the drilling jig for the steam ports. After that I turned the column to shape. I don't work with steel enough to get a good finish all the time. The tapered section turned out very coarse. Just need more practice.

Eric

[EricB]

Day two, on to the mill.

The column has flats for the cylinder and crank on one side, and to clear the flywheel on the other. The flywheel side was first.

After that I started drilling some holes. The crank hole is 5/16." Now I have a drill and a 3/8" chuck, but I didn't have enough Z travel for it to fit. I figured that out after I got started of course. I went ahead and drilled the cylinder mounting hole and its counter bore, then came back and bored the crank hole to size. Then I made the crank locating pin for drilling the steam ports.

The drilling jig is made of some kind of brass that I thought was free machining. It isn't. I tryed to cut it to size with a slitting saw and it was un cooperative. It cuts OK with an end mill though.

[EricB]

Day three, steam ports.

I used the same mill setup for as many operations as I could. When I made the Tiny I held all these bits in place by hand and marked the positions then drilled. This time was much easier. I had to go back and mill an extra bit of clearance for the jig. My attempt to save a few turns of the hand wheels did not work out.

The steam input is taped 3/16" MTP.

[EricB]

Day four. I didn't make much, but I took all day doing it.

The crank bearing is suppose to be a press fit into the column. Well I got it snug but removeable for now. It will be held with locktite later and an oil hole drilled once I'm happy with all the fits. I reamed the bearing to size. I tried to just drill it when I made Tiny, and ended up making a reamer and another bearing. Just made the one bearing this time.

The column was cutoff after the the bearing was fit. The top of the column has an odd pattern from a slight misalignment of the cuttoff blade. We'll just call that a decorative feature for now.

The last part for today was the column foot. I don't have any steel in the size needed so it's made of aluminum. Doesn't look right but it will have to do for now. A few hours of work went into that washer.

[MJM460]

Nice going, Eric.  It looks like a fun little engine to build.

MJM460

[EricB]

Nice going, Eric.  It looks like a fun little engine to build.

MJM460

Thanks, I'm enjoying myself.

[EricB]

So, why does it take me several hours to make what's basically a washer?

I started with a cutoff of aluminum from the leftover pile, flycut one side for the reference surface (this would become the top) and cut it down to size.

After listing and pondering the virtues of various fixturing methods to make the piece circular, I decided on a glue chuck. For that I refurbed a mandrel I had used on my first engine project. The mandrel used a bolt to hold the other engine and this came in handy later for removing the part.

I left the center in place while turning the outside diameter just in case, and then faced and relieved what would be the bottom of the part. So far, so good.

I used a center drill to make a pilot hole. The idea was that I could remove the part and resurface the chuck, then use the center and the pilot hole to align the part to finish the top side. Unfortunatly, I did not drill all the way through the part. That's OK, it turned out I couldn't have aligned it using that method anyway.

My solution was the 4-jaw scroll chuck. I was able to hold the part centered, face the top, bore the center for the column, and put a slight chamfer on the edge. There was not much room for error, and no way to remove the burr on the outer edge while turning. I'll need to make another mandrel to adjust the finish.

About 4 hours.

[EricB]

Day five, crankshaft.

Elmer said this "doesn't require much explanation" so...

[crueby]

Nice progress!


That second picture looks like its an Easter Island statue of an engine!


 

[EricB]

Nice progress!


That second picture looks like its an Easter Island statue of an engine!


 

It has an alarmed look doesn't it? I'm not sure that's justified. 

Here is the completed crank shaft.

[EricB]

Day six, the flywheel.

Started the flywheel from with length of 1.25" brass hex bar and a hack saw. It cuts much easier that aluminum by the way. Faced the sides parallel and knocked off most of the corners and drilled and reamed to fit the crank shaft stock, 3/16" drill rod.

To finish the OD I returned to my favorite glue chuck. This time it too was drilled and reamed for the drill rod. When assembled the drill rod kept the flywheel on center. I made sure the drill rod stayed loose as the glue cured, but left it in place for the turning. I ended up about .006" undersize once all the flats were gone. It's still too wide but I haven't decided how I want it to look yet.

Eric

[EricB]

I started on the cylinder before being forced to quit for the night.

[Chipswitheverything]

Thanks for the well photographed build log of an attractive little project, might encourage the making of a few more of these engines that can be made up from odds and ends of workshop stock materials.  Dave

[EricB]

Thanks for the well photographed build log of an attractive little project, might encourage the making of a few more of these engines that can be made up from odds and ends of workshop stock materials.  Dave

Thanks for the comment.

I know it isn't a technically complex build, but for me it's part of the learning curve.

[EricB]

Day seven, more cylinder work.

Here is the rest of the cylinder so far. It's not mechanically complete yet. I need the piston and rod in order to drill the steam passage. It's also not in it's final form. The plans show it with beveled edges along the outside. Not sure I want to copy that to do something else.

[Kim]

Nice progress on your new little engine! 

... for me it's part of the learning curve.

Yes, it's all part of the learning curve. And that, to me, is what makes this hobby so much fun - there's always something new to learn!

Kim

[EricB]

Nice progress on your new little engine! 

... for me it's part of the learning curve.

Yes, it's all part of the learning curve. And that, to me, is what makes this hobby so much fun - there's always something new to learn!

Kim

Thanks for the comment. So far I'm learning how adapt the design to fix, or rather cover, my mistakes. I probably can't make interchangable parts.

Eric

[EricB]

One more set of parts before quitting time today. I made the piston, a "nut" for the cylinder retaining spring, and the conecting rod. The object was to use every tool in the shed I hadn't touched yet, like the follow rest. Incidently, the Sherline follower rest will let you know if your headstock is out of alignment.

When I made the crank pin I used the closest size piece of unknown steel rod I could find and filled it down to a press fit in the crank disk. It was pretty hard to work with but does the job. The problem is now the crank pin is slightly oversize to fit the connecting rod. Once I get the steam passage drilled in the cylinder I'll need to make a custom reamer to match the crank pin diameter and enlarge the big end of the connecting rod to fit.

[PaulR]

Did you use a parting tool for the oil rings in the piston? The plan I'm roughly working to calls for 0.5 x 0.5mm slots. I don't have a ready made tool that narrow so used the end of a screw-cutting tool, turns out it wasn't a good idea as it churned up the edges a little and I had to carefully file them away the burr. Should have just gone with parting tool width slots instead 

[mklotz]

... turns out it wasn't a good idea as it churned up the edges a little and I had to carefully file them away the burr. ...

Next time stop turning the piston when it's about ten or 20 thousandths larger than desired.  Cut your grooves, then finish turning the piston to size.  Those last passes on the piston will remove any burrs left from the groove cutting.

[EricB]

Did you use a parting tool for the oil rings in the piston? The plan I'm roughly working to calls for 0.5 x 0.5mm slots. I don't have a ready made tool that narrow so used the end of a screw-cutting tool, turns out it wasn't a good idea as it churned up the edges a little and I had to carefully file them away the burr. Should have just gone with parting tool width slots instead 

I made a special tool, more like a trepanning tool, to finish the cylinder on my first engine. It's become my go to tool for brass. I angled it into the piston so only a corner makes contact, leaving the grooves "V" shaped. It doesn't leave a burr.

Eric

[EricB]

Day eight.

Drilled the steam port in the cylinder and lapped the column and cylinder port faces together. After that made the first of several springs to hold the cylinder in place. This one was too heavy.

I finshed the flywheel to it's final thickness and added som decorative grooves. I ended up using the plan design as a guide. Then the set screw hole was drilled and tapped. The plan reccomends a set screw bearing on a pin to hold the flywheel in place. I made a single piece screw instead.

With the flywheel finished I had enough parts to give it a test run. Success!

The next task was permanent installation of the bearing with loctite and drill the oil hole for the crank. Seemed like an easy task on paper. The problem started when the loctite started curing before I got the bearing seated. This was followed by much adult language as I tossed all my parts bins looking for something I could use to get some clearance as I squeezed the bearing into its bore using a vise. As I said earlier the bearing was a snug fit to begin with, but I got it all the way in.

The oil hole is an angled hole into an angled surface so I plunged in with a 1/16" endmill very cafefully.

Last today I made another spring for the cylinder. It's made from 0.020" brass tension wire, which a clockmaker's product. It runs much better with the lighter spring. I'm thinking I should have polished the wire before coiling it. I might have to make another.

The only things left are shaping and polishing the outside of the cylinder and finishing the column foot.

Eric

[Admiral_dk]

Acetone will completely dissolve just about all kinds of Super-Clue ...!
So you should be able to take the >Crank apart again ....

Sorry my bad - Locktite needs Heat to take apart 

Per     

[internal_fire]

There are many types of Loctite, but a favorite strong one is 648.

The technical data sheet notes:

"For Press Fitted Assemblies, apply adhesive
thoroughly to both bond surfaces and assemble at high
press on rates."

(Emphasis added)

In my experience the allowed time for fixing is only a couple of seconds even with a slip fit.

Lesser strength products, such as one might find in an auto parts store, will give a bit more time.

Gene

[mklotz]

... The plan reccomends a set screw bearing on a pin to hold the flywheel in place. I made a single piece screw instead....

A steel setscrew can raise a burr on the shaft that makes it difficult to remove the flywheel.  A short brass rod between the screw and shaft prevents that from happening.

[crueby]

Or file a flat where the set screw will be. Either way works.   

[EricB]

... The plan reccomends a set screw bearing on a pin to hold the flywheel in place. I made a single piece screw instead....

A steel setscrew can raise a burr on the shaft that makes it difficult to remove the flywheel.  A short brass rod between the screw and shaft prevents that from happening.

I get that. I don't think I'll have that problem. The shaft is drill rod and the screw is 12L14, and I rounded the end. I don't think I can put enough torque on the slotted screw to raise a burr. I have had that problem with allen set screws though.

Eric

[EricB]

Day nine, final machining.

I decided to follow the plan design for the outside of the cylinder as well, so I needed a way to hold the part while I knocked off the outside corners. After considering and discarding various ways of using the mill vice, I opted for an expanding mandrel held in a 4-jaw on a rotary table. I already had most of the mandrel completed already in the soldering fixture I use for the cylinder pivot pin. Starting with that I drilled it through, from the big end, for a 10-32 tap. I followed that with a clearance drill for the OD of the tap I was using. The tap I have was too short to reach the working end of the mandrel, and I needed to get at least half way though the working end. After that it was slotted, cleaned up, and ready to use. I had to borrow a longer machine screw from one of my other tools to expand it, and that was accessed from the spindle side of the chuck.

First up was a test with the column foot. I had wanted to put a better bevel on the edge so now was the time. After dialing it in it worked like a charm. I didn't want to fix the foot to the column with loctite, I may want to replace it with a steel part later, so I used a little too much superglue that I'll need to clean up.

On to the cylinder, dialed it in using the turned boss at the bottom. On the mill I had to align the back side perpendicular to the spindle axis before making the cuts. Again it worked fantastic.

I'll post a video of it running after I clean it up and polish the brass parts.

Eric

[PaulR]

... turns out it wasn't a good idea as it churned up the edges a little and I had to carefully file them away the burr. ...

Next time stop turning the piston when it's about ten or 20 thousandths larger than desired.  Cut your grooves, then finish turning the piston to size.  Those last passes on the piston will remove any burrs left from the groove cutting.

Thank you, why didn't I think of that? 

[PaulR]

Did you use a parting tool for the oil rings in the piston? The plan I'm roughly working to calls for 0.5 x 0.5mm slots. I don't have a ready made tool that narrow so used the end of a screw-cutting tool, turns out it wasn't a good idea as it churned up the edges a little and I had to carefully file them away the burr. Should have just gone with parting tool width slots instead 

I made a special tool, more like a trepanning tool, to finish the cylinder on my first engine. It's become my go to tool for brass. I angled it into the piston so only a corner makes contact, leaving the grooves "V" shaped. It doesn't leave a burr.

Thanks for the pic. That's what I was aiming for with the pointed tool I used but it probably didn't have suitable relief.

[EricB]

<a href="https://www.youtube.com/watch?v=zfXA5Z67e0Q" target="_blank">http://www.youtube.com/watch?v=zfXA5Z67e0Q</a>