Tom Thumb with Stevenson

[Bill Shields]

Here is an assembly showing the modifications Jim and I had to do to get Stevenson gear on the Tom Thumb engine without modifying any of the castings.

Since the engine was designed to run single direction (one eccentric), the 2nd eccentric for the Stehpenson is offset quite a bit..looks a little 'different', but it runs quite well.

Next step - mount it on the engine and get rid of the forward / reverse gearbox.

OK...so how do I post a picture now?

[This message has been edited by Bill Shields (edited 06-03-2006).]

[Jan-Eric Nystrom]

<font face="Verdana, Arial" size="2">OK...so how do I post a picture now?</font>

First, you must load your picture(s) onto a server - your webpages, or any free web photo gallery.

Then, get the exact address for the photo itself, not the page it is on. (The photo's address usually ends in ".jpg".)

Then, paste the address into your message, and put before, and after the address.

Here's an image I linked just as described above, showing yours truly:

http://www.saunalahti.fi/animato/homepg/ears.jpg

Click the edit icon above this message (the one with a pencil), and you can see the above code in use.

Hope this helps...

Greetings,
J-E


[This message has been edited by Jan-Eric Nystrom (edited 06-03-2006).]

[willy]

Here you go Bill. From the chaski site.
http://www.chaski.org/homemachinist/files/tom_thumb_stevenson_988-resized_135.jpg
Willy

[Unka Jesse]

Neat Bill, but what is the diagonal con-rod that seems to attach to an outside crosshead for? Feed water pump?

Unka Jesse

[Bill Shields]

DUH...I got used to the Chaski board where you just 'attach' the picture.

gettin old.

Jesse:

I don't follow your question...you are probably being fooled by the bad photography. The feedwater pump is gear driven off the far end of the crank...where the lump of cast iron is that is currently working as a flywheel. None of my pictures are very good. I will take from another angle.

[pockets]

I see what Jesse is talking about. It looks like there is a rod going into the bottom of near side exhaust fitting.This appears to be connected, via another rod, to the crank.

Then, again, it might just be my bi-focals....

J-E, you have my condolences. According to my wife, you look enough like me (20 years ago) for us to be brothers. Without the MM ears, of course.....

Greg B.

[This message has been edited by pockets (edited 06-05-2006).]

[willy]

Yea I thought that about the rod as well. Yet after looking at it closer (saving to my hard drive and expanding it) I realized it was some interesting photography and is only the rod for the furthes cylinder.

Good work Bill. http://bbs.livesteam.net//biggrin.gif

Willy

[Bill Shields]

what you guys are looking at is the crosshead for the behind cylinder...the photography leaves a lot to be desired.

this engine is basically now a little steamboat twin cylinder plant, using one casting to hold everything together.

it is a bit of a cob job because of the offset between the eccentrics and the valve rod, but you have to live with what you have to live with. I thought about putting a sandwich valve port plate under the chest and simply moving the valve out to the line of the eccentrics..then thought better of it.

looks a bit strange, but then most of my work looks strange...but it runs well.

[Unka Jesse]

Bill, after squeenching my eyeballs in various configurations, I can see what you meant in the email to me today about this photo. The con rod and guide are indeed for the far cylinder. That is the problem with a two dimensional photograph as opposed to a 3D one.

Unka Jesse