Lauson LA build

[Craig DeShong]

Thanks for all the encouragement; especially Bill, Brian, Art, and Per who have recently commented.  Thanks also for others who are silently following along.
 
The flywheel did absorb DAYS of time, but it was kind-a fun to do as it involved going a few places I haven’t ventured before, though it involved a lot of repetition.  Most of the face work (outside face of the flywheel) was done with one (1) carbide ¼ inch end mill.  I thought for sure I’d have to replace it at least once but it kept “hanging in there”.   Sure wish I remember where I got it so I could get a few more.      
 
In the past week or so I’ve gone back and finished quite a few odds and ends; you know: those tasks that individually don’t take much time and aren’t particularly hard, but cumulatively, can burn up days of effort.  Still, they need done if you’re going to produce a finished model.

I decided it was time to close the block.  This required attaching the crankcase breather that you see at the rear left side of the block in the following photo. 



Also in the above photo you get a fairly good view of the governor cap.  I now have the knurled knob protruding out the back that allows adjustment of the governor.  An internal spring bears against the governor spindle that was the topic of discussion on post 115 up thread.

I also fabricated the intake manifold (though some additional filing/forming is required).  Once I fabricate the carburetor I can glue up the connections and position it properly.  It shows prominently in the photo below.



I thought I’d go ahead and make the muffler.  This is my attempt at a reproduction of the standard muffler Lauson used for many of their engines and it appears on several of my other models.



Also, in the above photo and the one below you see the kick-start bracket that holds the kick-start mechanism to the front of the engine block.  While all the other attachments I’ve “glued” to the block are for the most part, cosmetic; this bracket is attached to three protrusions recessed in and "glued" to the front of the block.  It will take some stress if I intend to use the kick-start mechanism to start the engine (and I’d sure like to do so).  We’ll see how this holds up.  I used JB Weld to “glue” these parts, it’s worked with mixed success in the past.

 
With all this “gluing” I thought I’d prime the model so I could see how well I have the glue joints blended to the body; remembering that the block in the full size was cast as one piece and I’m trying to replicate that.  The paint shows that I have a bit more “feathering” to do at a few places to simulate a piece cast as one part.  All in all though, I'm pleased with the progress.

[10KPete]

That is a really great model, Craig. I've followed along for most of your build and I admire your patience and skill.

Please don't forget to post more, and a video, if you can. It will be good to see it run.

Congratulations!!

Pete

[Brian Rupnow]

Craig--I'm old enough to remember when all of the clothes washing machines were powered by similar kick-start Briggs and Stratton or Iron Horse single cylinder engines. This was back in the early 1950's before hydro-electricity came to my part of Ontario.---Brian

[Dave Otto]

The little Lauson is looking great Craig!


Dave

[b.lindsey]

Nice to see this update Craig. It's really coming together now and will make a fine addition to your Lauson collection.

Bill

[gbritnell]

Craig,
What an outstanding build! Eventually all the pieces come together and create an amazing miniature replica. The icing on the cake will be to hear it putting along.
gbritnell

[Craig DeShong]

Pete: thanks for posting.  Yep, we’re getting near to the first “trial” run.   This usually brings with it some “issues” to work out, but then that’s part of the fun too.

Brian. Bill, Dave, George: thanks for following along and all the encouragement you’ve provided.

George: Thanks again for your wisdom regarding the helical gears; I’m not sure this model would have moved forward without your assistance.  And believe it or not, I’m not finished yet with helical gears with this model, the kick start mechanism also uses them and that will provide its own set of unique challenges.

Thanks also for those silently following along.   

I’ve spent the last few days carving away on this piece of aluminum,




trying to coax a carburetor body from it;  lots of setups and lots of steps were required.  This is the fourth of these Tillitson type carburetors I’ve made and you’d think by now I’d have it down to a fine science.  Not so however, it seems like I just I just keep hacking away at the aluminum block till a carburetor appears.   I never seem to follow the same steps, of course all the carburetors are different; but mostly from a cosmetic standpoint.
A good way to start is to get some of the major passageways and holes drilled.  I’ve found that doing so tends to avoid dumb errors.  You might absent mindedly mill away needed material, but you probably won’t if a required hole is in the path.  Here I’ve started forming the mounting flange that attaches the carburetor to the intake manifold.  I’ve drilled the throttle side of the venturi and have just finished drilling the two mounting holes.

     
Now I’ve flipped the piece over and am forming the other side of the venturi and the mount holes for an air cleaner.



Skipping over a few steps, Here I’m forming the float and fuel inlet chamber.



A few more steps later I’m in the process of drilling and taping the receiver for the main needle and needle seat.

 

Advancing a few more steps, I’m forming the carburetor mounting flange using my rotary milling head.  The rotary milling head has been on and off the mill all day and has been used extensively to form all the curved surfaces.



Here I’m forming the air cleaner flange.


Finally, I give you a few views of the finished carburetor body.
This view is looking down on the top, from the back of the carburetor.  Clearly seen is the float chamber.



This is another view from the back of the carburetor.  On the left front you can see the opening for the throttle barrel.  Lower down, on the diagonal member (to cosmetically simulate the full size carburetor) are two opening that will be plugged when I complete the carburetor.  The bottom opening is a drilled passageway that crosses through the main needle chamber and on to the bottom of the float bowl chamber.  This passage delivers gas from the float bowl to the area under the main needle seat where the main needle can regulate the amount of fuel available to the venturi.  The higher opening is a passageway into the area above the needle seat.  A hole, drilled from the top of the carburetor body intersects this passageway and allows the higher ambient atmospheric pressure (higher than in the venturi) to lift fuel into the carburetor throat.

   

This is a view of the bottom of the carburetor.  The hole in the center left is a float bowl drain and will be closed off with a set screw.  The hole on the bottom upper right is the entry for the main needle seat and gland.

 

Now, with the carburetor body complete my attention will be focused on making all the parts that make this a functioning carburetor.  I need to make the main needle, needle gland, and needle seat; the throttle barrel and choke barrel; the carburetor lid and float bowl shut-off valve.  I need to also make the float- but more about that later.

[zeeprogrammer]

Thanks also for those silently following along.   

Yes...I'm one of the silent.  It's really interesting.

[Craig DeShong]

Did you ever have one of those days where NOTHING goes right? For me, that would have been yesterday: just a calamity of errors and problems .  I managed to make a needle valve and needle seat, but it took the whole blessed day.  Everything was going wrong, including dropping a die and hearing it roll across the floor to who knows where?   Now I don’t consider my shop particularly messy, but it took over half an hour to find it, though in the process I did manage to clean a few far reaching corners that haven’t had the experience for quite a while. Today was much more productive and I managed to complete the carburetor and carburetor parts.

Below you’ll see the carburetor and all the parts. 

The left column is the main needle, backing nut, gland, and main needle seat.
Center column is the choke barrel, above the throttle barrel, and above the carburetor body.
On the right is the float, directly above the fuel bowl shutoff valve, and above that the carburetor cap with valve seat installed.


The main problem I have in building these carburetors is getting the fuel shutoff valve to function reliably.  The float is so small that it has very little lifting force.  I’ve gone to using a cut-off needle of approximately .035 inch diameter as the valve.  The float lifts this needle up into a drilled chamber of around .052 inch diameter where it seats into a hole drilled at the top of the chamber to .025 inch diameter.  With some fiddling I can usually get this to work.

The float is the end of a wine cork that is around ¼ inch thick and has a diameter of around 5/8th inch.  I treat the cork with gas tank sealant.  For this go-round I’m trying a very thin metal cap (.010 inch) on top of the float so the needle doesn’t dig into the cork over time. 

After long and extensive testing of wine corks under the most rigorous of scientific methods I've found that the corks from Merlot are unacceptable, as are the corks from Zinfandel, Chardonnay, Sauvignon blanc, Syrah, and Pinot Noir; a cork from a semidry Riesling seems to work best   (jeez- the sacrifices we make for this hobby).   

[Tennessee Whiskey]

Dang, I thought I was the only one that had to resort to multiple tastings of an adult beverages to reach a solution  . Work is looking awesome Craig. I would venture to say that valve sealing and carburation is the hardest aspect of this sport.    &    here.

Cletus

[Craig DeShong]

Cletus: In the afternoons you’ll often find an open beer in the shop.   I think it helps to “soothe the savage beast”.

Progress continued on the one thousand and one odds and ends in my quest toward seeing if this model will run.

First on the list was building a stand for the engine.  I usually make a wooden box where I can place the coil, condenser, various wiring, etc.  Here I’m making the finger joints on the box with my “ToolMaster FingerJoint 1000 ™“ 

more commonly known as a Bridgeport Milling Machine

I feel a little guilty using a milling machine for woodwork, but it does make beautiful finger joints, and it makes them so easily that I think even “Bozo the Clown” would be successful.

I decided to paint the model before trying to run it.  I had it all apart and cleaned when I epoxied the several components to the block I mention in the above post and while it was disassembled and cleaned I figured I might as well paint.  It looks a bit different since the last time you saw it; but still lots to do before I can call it complete.  I still have a few items to address before a test run, but the list is getting shorter.

[Brian Rupnow]

Craig--It's a beautiful thing. I can't get over the amount of work it must have been to make that flywheel. Good luck.--Brian

[AlexS]

Craig, It looks cool! Are you also planning to scale up a washing machine or something? So that the engine could power it?

[kvom]

I've always wanted one of those BP right angle attachments but can't justify the money whenever I see them offered. 

I assume the finger joints could be done with the board mounted vertically although obviously the hold in the vise is better as you have it.

[gbritnell]

Dang! it looks like the real thing!