Monitor, A Half Trunk Vibrating Lever Back Acting Engine

[Captain Jerry]

Well, I may have a handle on the valve control link.  It at least honors the method that Ericcson used in spirit if not in detail.  The hand wheel turns the front vertical shaft which includes a threaded section at the top end.  The brass follower captures that thread and drives the valve rod (the rear vertical shaft) up or down to open or control the valve.  I have tested the valve with lung power but I wont really know until I am ready to run the engine how effective it will be under higher pressures.

Vcontrl0005 by captain.jerry Ginn, on Flickr

Vcontrl0004 by captain.jerry Ginn, on Flickr

The lower support bracket looks a little too heavy so it may get some attention.  The valve rod will be cut off just below the follower.

[Captain Jerry]

This is a test.  I will describe it later.

This is a video on my Flicker page.  Click on it once to get to it on Flicker, then click on it again to play.  If you click on the double arrows in the upper right corner of the flicker page, it will expand to full screen and and replay continuosly

VID_20161203_152451 by captain.jerry Ginn, on Flickr
That is experiment number one.  I just wanted to see how Flicker would handle HD videos.  Let me know how this works for you.

Experiment number 2 is the action.  With all of the linkage components completed and modifications made to  the crank follower to provide reverse, I needed to verify the clearances and check for balance and freedom from tight spots.  With just a few spacers beneath the frame for alignment, it matches up very well with my Unimat SL.  I can't find the low speed belt for the Unimat so it is hooked up to an electronic speed controller to provide a very low operation speed.

It would be possible to check for clearances by hand rotation but that only gets a few revs at a time and gets tiring very quickly.  I have a variable speed drill that I have used before but that is so loud that it hides any little knocks, scrapes, or ticks.  The Unimat is nearly silent and easy to control. 

I have tested and fiddled with this for a while and was able to find and fix a bearing alignment problem causing excess friction on the eccentric shaft that turned up when the bearing retainers were snugged down. 

[crueby]

Motion looks great!

Have not seen a unimat sl in a long time, one was my first lathe many many years ago.

[Captain Jerry]

The previous post has been completed with a full explanation.

The Unimat was my first lath as well.  It still gets a lot of use.  My 9x20 doesn't have the high speed for turning small diameters, but it usually has a small diamond disk that I use for sharpening carbide lathe tools and boring head bits which is all done freehand.  One of these days I will get around to building some guides.

[Captain Jerry]

This engine is moving along but it not moving fast.  I think that all of the parts have been made and the task now is to put them together so that they don't irritate each other.  With so many parts in such a confined space getting that necessary cooperation can  be irritating to the builder. 

Assembly order is more important than I had anticipated and that also applies to sub-assemblies, but I believe that those mountains have now been climbed.  I have spent the last few weeks working out some territorial issues caused by something rubbing something else the wrong way, and running down an annoying little "tick" caused by a cylinder that was a hair to short allowing the piston to tap on the head at the end of the stroke.

I have no one to blame but myself for all of these problems.  The dimensions are all mine.  I had worked them out from observation of someone else's model, which I have only seen on the computer screen with no dimensional information.

I am very close to hooking up an air hose so I can start tuning the valve timing and trouble shooting all of the leaks.  Here is how it looks today.---

[youtube1]https://www.youtube.com/watch?v=SR0nKn5t9r8[/youtube1]

The video turns up one more little fix that needs attention.  There is a brass bearing on the eccentric shaft that does is not firmly seated in the frame.  It was not clearly evident until the reversing control wheel was installed and becomes very obvious in the video.
                                                                                                         8431
 

[Flyboy Jim]

This engine is moving along but it not moving fast.  I think that all of the parts have been made and the task now is to put them together so that they don't irritate each other.  With so many parts in such a confined space getting that necessary cooperation can  be irritating to the builder. 

Assembly order is more important than I had anticipated and that also applies to sub-assemblies, but I believe that those mountains have now been climbed.  I have spent the last few weeks working out some territorial issues caused by something rubbing something else the wrong way, and running down an annoying little "tick" caused by a cylinder that was a hair to short allowing the piston to tap on the head at the end of the stroke.

Kinda reminds me of my first marriage.................I think we had "territorial issues"! 

Anyway, the video looks great! Nice and smooth. Still gotta get my head wrapped around how you could remove the steam chest covers.

Jim

[crueby]

Jerry, that is looking great! The piping really is spot on, and I'm amazed at how well the piston rod in a tube worked out.

Jim, think wizard of Oz and look at the man (lathe I think) behind the curtain driving the shaft... Very clever.

 

[Flyboy Jim]

Jerry, that is looking great! The piping really is spot on, and I'm amazed at how well the piston rod in a tube worked out.

Jim, think wizard of Oz and look at the man (lathe I think) behind the curtain driving the shaft... Very clever.

 

Well............isn't he the sneaky one! 

Jim

[10KPete]

Looking good there!! Also noted the left side slide valve seems to be hitting something end of outward stroke at the bottom outer corner.....

Keep it coming!

Pete

[kvom]

It was hard to know the size of the engine until I saw, first the Unimat, and second your hands on the covers.  Very nice.

[ShopShoe]

That's coming along nicely. Looking forward to see it really running.

Thanks for bringing us along for the ride.

ShopShoe

[Captain Jerry]

Jerry, that is looking great! The piping really is spot on, and I'm amazed at how well the piston rod in a tube worked out.

Jim, think wizard of Oz and look at the man (lathe I think) behind the curtain driving the shaft... Very clever.

 

Well............isn't he the sneaky one! 

Jim

Thanks, Chris.  The piping was a challenge but the "piston rod in a tube" was the real attraction of this engine.  It has worked out much better than I anticipated.  The geometry and the clearance calculations entertained me for quite a while.  My solution is  adequate for this model but there is one detail of it's construction that I was not able to achieve.  In Ericsson's design, the wrist pin bearing is a split bushing and the wear is taken up using the gib/wedge at the opposite end of the rod.  I had to use a brass wrist pin and hope it doesn't wear too quickly.

Jim! What do you mean sneaky?  That was a carefully contrived obfuscation! 

Thanks, Pete.  I spotted that little hop at the end of the valve stroke in the video.   The square corner of the valve body is hitting the radius in the corner of the valve chest.   A few strokes of the file will take care of that.  There are probably lots more of those little refinements that will be needed.

Thanks for your comments