Elmer’s No.19 (Art Deco Version)

[Mark EasingwoodParticipant @markeasingwood33578]

 

I recently completed my first engine.

Having followed the link in a recent thread about the forthcoming Midlands Model Engineering Exhibition, to the Elmer’s no.19, as drawn and built by John on his “Journeyman’s Workshop” website, I decided to make my own version.

Journeyman’s Workshop.

I used John’s drawings, available on his website, as the basis of modelling my own “Art Deco” version in Alibre Atom, which I have also been learning. I used the same bore size of 14mm and a 50mm flywheel, some other dimensions were altered to suit the available material.

Not all was perfect first time, I re-made the cylinder, as the first one I bored a little oversize, too busy concentrating on getting a good finish on my well worn Little John lathe, so I didn’t check the size often enough! As I had drawn it at 20mm square, the front cylinder wall was left looking a bit thin, so I re-drew and made a 21mm cylinder.

Once I got the valve timing set right, it ran nicely without any issues.

The cylinder bore was honed with a strip of emery in a slotted wooden dowel. The brass and stainless steel parts got a polish, and the aluminium got a rub on some fine wet & dry, lubricated with WD40. The wooden base is American Cherry, finished with Osmo Oil.

The flywheel has a very slight wobble when running, I think this due to using nominal 6mm stainless steel for the crankshaft, and a 6mm reamer for the flywheel, giving a “running fit.” The single grub screw fastener then pulls/twists the flywheel. Although I did select a piece of bar, for the crankshaft, which was as near as possible to 6mm diameter, checking it with a micrometer.

Should anyone fancy making one, I can make my pdf drawings available, and of course John’s drawings are on his website, he also has details link to the original smaller version.

Modelling in Alibre Atom.

All the Parts.

The completed Engine.

I also produced my first (short) YouTube Video, of the engine running.

Mark.

[JasonBModerator @jasonb]

You have made a nice job of that. The bit of extra effort to add the details lifts it above just another barstock engine.

Small flywheels can always be a bit of an issue as they are a bit hard to get into with a boring bar and the typical reamers while Ok for bearings where you want a bit of a running fit tend to make flywheels a bit loose. A second grub screw at 180deg or two at 120deg spacing may allow you to tweak the minor wobble.

 

What’s next?

[JourneymanParticipant @journeyman]

Well done Mark.  Nice job that and a good little runner.   Being a bit bigger than Elmers’s original makes it just a bit easier to build I found.   Elmers book with all the plans is online at the link given above (in the download section) for anyone else that fancies a go at a small stationary engine.

John

[Mark EasingwoodParticipant @markeasingwood33578]

Thanks Jason.

I did wonder about adding another grubscrew to the flywheel, it does look worse in the video than it does in the real world tho’. I can be too finicky sometimes!

The 3D Cad drawing programmes certainly make it easier to visualise, and alter/add details on projects.

The idea to add the detail, to make it “less barstock,” stems from reading your build threads over the last few years.

As to what’s next, I recently bought Stewart Hart’s book, so maybe a “Potty Mill,” although I also started to draw an “Elbow Engine,” but I read they can be difficult to get running, or perhaps one of your engines.

 

 

Thanks John.

I hadn’t discovered that part of your website, until now.

Mark.

[Craig BrownParticipant @craigbrown60096]

Engine looks great 👍

[Clive FosterParticipant @clivefoster55965]

Mark

Flywheels are the very devil on such small engines, a couple of thou run out stands out a county mile when its running and draws the eye like supercooled electromagnet. Even more so when nicely polished.

Once you’ve seen the runout you can’t unsee it either.

Which totally spoils the, justly earned in your case, satisfaction of making a nice job of the engine.

Best practice with grub screws is two at 90° which gives wobble free results so long as the fit is close to slip with both bore and shaft nicely finished.

Gotta say I’m a bit unconvinced as to whether these very small engines are the best subject for a neophyte having to simultaneously learn to both machine parts and coax the best out of a machine well past the first flush of youth with the inevitable vagaries of operation and execution. In absolute terms the actual size of any errors is likely to be pretty constant but on an engine twice the size they will show up half as much.

When it comes to cylinder boring it’s far harder to do a 20 mm one than a 50 mm one. Quite apart from the difficulties of getting the right shape on a tiny boring tool it’s a darn sight easier to see whats going on inside the larger bore. Concerning boring tools it would have made my life far easier on many occasions if someone had told me Jasons trick of using an end mill at a slight angle ages ago. 1974 sounds about right!

Tolerance rings are well worth remembering about. They can be got right down to 4 mm diameter and are great for recovering things should you sneeze at the wrong moment and overcut. Far as I’m concerned whatever works is good and the screaming purists can go back to their “best howler monkey impersonation” competition. At least they seem to have finally accepted loctite.

Although regrettably rare the hand squeezed “nutcracker” type three wheel  knurling tools are great when it comes to converting a nice slip fit to something a bit more grippy. A quick squeeze leaving a very shallow pattern is just the job for tuning easy slide into nice stiff push ready for two grub screws or loctite for final hold. I’d really miss mine.

Clive

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