Elmer's Fancy II

[paul gough]

A method I find very convenient with my Sherline is to turn the barrel of the cylinder then transfer the chuck to the mill by using the chuck adapter, mine is in the rotary table, then spot drill (120 degree), drill and ream the bore. I get satisfactory results in brass without the need for lapping. This ability of swapping chucks from lathe to mill or vice versa is a very useful feature. With the 4 jaw on the rotary table I still have a bit over 150 mm (160 with 3jaw), of distance between the top of the chuck jaw and the face of the ER 16 collet nut. Plenty for my 9.5/10 mm cylinder bores. Probably enough room, just, for 12/13 mm if you shortened the shank on the drill, which I do, as the 10 mm ER collet can cope with a 12mm drill in brass without any issues. The Extra height with the 15 inch column is a boon, suggested by the Sherline master Chris Rueby. I find the ER 16 spindle lathe and mill excelllent and accurate. Regards, Paul Gough.

[EricB]

Paul, Thanks for the insights. I considered drilling and reaming on the mill or drill press, and though I could get the bore to size, I could not figure out how to get it to depth and achieve the geometry needed at the blind end. If I drilled to depth at the point of the drill I'm left with a 120 degree cone shape and no clearance for the end of the reamer or the top of the piston. I would still need to somehow shape the blind end of the bore. If I drilled to depth at the diameter of the flutes the drill point breaks through the end of the cylinder.

The diagram makes it look simple enough, and I have made other Elmer engines using similar paterns, also blind only smaller. For those I drilled and bored to depth and then reamed to size. The clearance drill for the boring bar was easily handled by my lathe, and I could flatten the blind end and make the relief "groove" for the reamer with the tip of the boring bar.

For this one the diameter and depth of the bore was the issue for me. I have a long insert boring bar, but the clearance hole is about the size of the final bore I needed. I think in the future I'l knock the carbides off the tips on my cheap inport bars and grind the remaining material to suit the task.

Eric

[paul gough]

Hi Eric, Sometimes my old brain gets lost, I forgot you are doing blind bores and my method applies to through bores. Hope I did not waste your time reading my irrelevancies. I am following your build for insights as I want to make the slide valve oscillator from Elmer, maybe try to incorporate a Penn link and reverse. Regards, Paul Gough.

[EricB]

Paul, No worries! I appreciate the input. My first Elmer engine was a slide valve oscillator, #42 in his book. I'm thinking of making another or a derivative of it. I've looked at several engines of that type and I can't figure out how you would reverse one.

Today I made another expanding mandrel so I could shape the outside of the cylinder after I finished with the other work on it. The plan has the outer curve centered on the 3/4" stock. I left the stock a little oversize so I could center the curve on the bore. The final dimensions I'm aiming for are 3/4" across the port face as per the plan, but 13/16" to the top of the curve. I may bevel the top edge too. We'll see.

Eric

[paul gough]

I too tried to come up with some sort of reverse, but failed to accomplish anything workable. Then stumbled on a Penn stationary engine with a curved link with further searching found Penn made a reversing marine engine, a working example is in a German paddle wheeler named the “Diesbar”. A low pressure, low rev, twin cylinder with slip eccentric reversal. Quite a mind stretcher to comprehend all the gear movement, at least for my rather feeble faculties, but as luck would have it a German model maker has built a replica of the engine. He authored a booklet (presumably still available as I only got mine some months ago). MichaelS And Crueby gave details to me. It is in German, but I fumbled my way through doing a rough translation. The drawings make most things understandable. It will be some time before I can get onto this project though. The details of the booklet are: Author is Josef Reineck; DAMPF 44, Die Diesbar Schiffsdampfmaschine, Neckar-Verlag, 2016. From memory I got a copy from a British supplier. Will try to find who and post it later. Regards, Paul Gough.

[paul gough]

Can’t find the seller I got it from for sure. But I used AbeBooks and they have it listed with Revaluation Books UK. US $27. Quite possibly my source, but there are many other offerings if you search the title and author. Regards, Paul Gough.

[crueby]

I think I  got my copy of the Diesbar book from AbeBooks too. I scanned the pages and ran it through OCR then a German to English translator, to get the text. I've  taken the plans in the book and made a CAD version, on my list to build someday too. The valve motion is quite interesting with a slip eccentric to do the reversing. The engineer has to disconnect the link and manually move the control rods for the start of the first revolution in the new  direction. There are a number of videos online showing it.

[EricB]

The engineer has to disconnect the link and manually move the control rods for the start of the first revolution in the new  direction. There are a number of videos online showing it.

So I guess there's no changing directions on the fly, huh? Interesting.

I spent too much of my wife's time talking about steam engines this morning so she banished me to my workshop. Oh darn.

Eric

[EricB]

I found a listing for the book on Amazon.

And this:
https://www.asme.org/wwwasmeorg/media/resourcefiles/aboutasme/who%20we%20are/engineering%20history/landmarks/245-john-penn-sons-oscillating-steam-engine-18.pdf

Eric

[crueby]

The engineer has to disconnect the link and manually move the control rods for the start of the first revolution in the new  direction. There are a number of videos online showing it.

So I guess there's no changing directions on the fly, huh? Interesting.

I spent too much of my wife's time talking about steam engines this morning so she banished me to my workshop. Oh darn.

Eric

In the videos online, it only takes the a couple seconds to change direction, at least for their experienced engineers!

[EricB]

In the videos online, it only takes the a couple seconds to change direction, at least for their experienced engineers!

I haven't found the videos yet. The engine has an interesting history!

Eric

[crueby]

In the videos online, it only takes the a couple seconds to change direction, at least for their experienced engineers!

I haven't found the videos yet. The engine has an interesting history!

Eric

Here is one. Shows the engine running in a couple places


<a href="https://www.youtube.com/watch?v=t4DiXpf2Zaw" target="_blank">http://www.youtube.com/watch?v=t4DiXpf2Zaw</a>


and another
<a href="https://www.youtube.com/watch?v=bDp8T91iIKE" target="_blank">http://www.youtube.com/watch?v=bDp8T91iIKE</a>
one more
<a href="https://www.youtube.com/watch?v=9G2WD09HtCc" target="_blank">http://www.youtube.com/watch?v=9G2WD09HtCc</a>
Oh, and if you turn on subtitles, then go into settings and pick auto-translate and English, it will give you the subtitles in english (tested on the third video, didn't try it on the others)

[EricB]

Back to my engine, I finished the major work on the cylinder. The final cuts were at 2.5 degrees per pass, that's 72 plus a few extra. I didn't keep track of the number of passes before that but it was lots of handwheel turning. I kind of like the finsh though.

I somehow did not get the cylinder pivot aligned with the body pivot. I laid them out and spot drilled both on the mill so I probably didn't get the backlash in the table leadscrew going in the same direction both times. I'll leave it.

Eric

[crueby]

Looking great! The rounding over came out fantastic.

[EricB]

Thanks Chris.

Once I got the corners knocked off the rest went fairly smooth. Tedious, but smooth.

Eric