25 HP Nash

[Sprocket]

I first saw this engine at the 2019 NAMES show. Can't remember for certain who had made it, but he also had a really nice Lanz tractor. I asked where I could get the plans and he said, "Be patient, watch Village Press ". If anyone knows the modelers name, help me out, that was some sensory overload, and while I took pictures, I didn't get good notes. Anyway I saw it again here, from Rustkollector, and he said the same thing, but now it was "very soon". and it was.
I got the book "The Engines of Doug Kelley" from Village Press. It has the Snow, Bruce Macbeth and Titan 5o, all were published in "Home Shop Machinist" except the Nash.
This will be my first multi-cylinder, water cooled, and based on a real engine, model.
A lot of the crankcase parts were made of brass plate, 1/8" or 3/16" thick, and the heads were 3/4 'by 1 5/8" by 2" also brass. I had the steel, would have had to buy brass, it looked pretty expensive.
So I made it out of steel. I'm sure brass is easier to fabricate, but it's steel
Crank case parts

Stacked up to look like something...

cylinder holes and access doors

and I started on the crankshaft
I made the webs double thickness and then split them

Flywheels came from Martin Models. I got a smaller one for the non- gear end because I think I want a generator to go there. The larger one is the one designed for the Nash, it's 7 3/4" in diameter



I haven't begun silver brazing yet. I've been making a lot of parts, and waiting until it was warm enough to braze in the garage with the door open. I did try a little in the shop, but it was too smoky for a
small room. Well, now it's warm enough, except that I'm having fun making parts.

Thanks for looking,
Doug

 

[werowance]

this looks interesting. replying so i get notified when there is an update.

also have a question, do you have a picture or image of what the final engine will look like?

 

[joerom]

Village Press has the book with this and other engines in it...It is "The Engines of Doug Kelley".............

 

[joerom]

I thought I would add a little more info on the book.. I have this book and it has some great engines in it and does not cost a lot, just in case the members here do not know about it.. I intend to make some of the engines... It has build instructions for the Nash, the Snow Engine, The Titan 50 HP Engine and the Macbeth Engine..

 

[Vietti]

Where do you get it? Amazon only lists the Snow book.

thanks, John

 

[kuhncw]

Joerom,

Thanks for mentioning Doug's book and posting the cover photo. It is a great source of plans and information for model engine builders.
I have a copy, and recommend it.

Chuck

 

[kuhncw]

John, you can order the book from Village Press.

Regards,

Chuck

 

[Sprocket]

Village press is correct :

The Engines of Doug Kelley
It is a very good book for not a lot of money ($28.00)
Doug

Werowance, The Nash is the model in the upper right corner of the book cover. there also is a video of the finished model here



the model is Rustkolector's, and you can see some of his photos in this thread

The Nash Gas Engine Electric Plant

 

[Sprocket]

I started to make the water jackets. Kind of an interesting problem to bore the undercut inside the water jacket. The inside contour sort of follows the outside contour, but you can't see what you are doing.

there is a mount piece that attaches to the bottom of the water jacket for bolting to the crank case

And cylinder liners that will be pressed (or he says, "shrunk") into the water jackets. They are just a tube when you are finished, but for a press fit in the water jacket, and piston fit inside


This will be two valve blocks when it is split in half. I started by boring the water jacket diameter, then shifted it .015 one direction in the 4
jaw chuck, back through center to .015 the other way. So this hole is .030 oblong, but it gives me room to make a saw cut in the center and
still end up with enough depth to come to the centerline of the water jacket.

So they look like this


Still nothing brazed together, but starting to look like an engine.

Thanks for looking

Doug

 

[cobra]

Nice work

 

[kuhncw]

You are off to a great start.

Chuck

 

[Sprocket]

Part of what I found attractive about this engine is the heads. There are 14 bolt bosses on each head, around a curved and radiused surface.
So 14 hex heads sticking up on top of each head. I think it just looks cool. But there are 28 little bosses to make.
I decided to leave the edges square as long as I could for easier holding and measurement.

the bottom of the head has a cut out for the coolant channel, and a plate is brazed in for the top of the combustion chamber. Rounded the front, and radiused the curve with the rotary table



Trimmed and radiused the straight edges, and stuck the bosses in just to see how it looked.

The bosses will be soft soldered after the top of the combustion chamber is brazed.

I think that's all for tonight. Thanks for looking.

Doug

 

[Sprocket]

I skip around a little when I make parts. Sometimes it's how much time I have or a set up I can use again.
Somehow I had a setup that would bore the about 1 9/16" diameter of the water jackets, so I made the mount pads for the water inlets
and the hand grip. They will be soft soldered on to the water jacket after brazing other parts.



The valve arms are another interesting part. They will be soft soldered to the crank case and support the cam shaft in the nearer hole and the rocker arm pivot at the end. These were also supposed to be brass, but I made them from steel too. The camshaft will run in a bronze bushing, and the rocker arm pivot in brass. They are a left and right with the only real difference being a ledge on the inner side, so I made one double thick, cut a ledge on each side and split it. The shape is "mill whittled" to get the shape and angles.





I continued to make little valve train parts, but that will have to wait ..

Thanks for looking,
Doug

 

[Sprocket]

Back again.
Next parts were the rocker arms. Not typical rocker arms, the cam rides on a wheel in the center of the arm, pivot at one end and lifter at the
other. They are tapered top and bottom, and narrow in the mid section with "dog bone" ends . They were spec'd to be 7075, but I didn't have any, so I practiced on some 6061 while I waited for the good stuff.

The 7075 came eventually. I started 6 when I needed 4. That was practice too.
(Why is it that when the supplier has a warehouse in CT and I'm in VT, they only have the right stuff in Seattle?)

With the rotary table centered under the spindle, I clamped the part also centered on the spindle on a sacrificial plate.

(I made a video of this, but I can't load it here. I'll get it on you tube later)
So, rounded both ends, thinned the centers
and slotted for the wheel and lifter.

The lifters are soldered from two pieces of steel. Plans say it is critical that they be perpendicular to the axis. so I mad a little fixture to hold them while I soldered.


And all the parts together



I've started brazing the crank case together. It's a little ugly right now. I'll post some pictures after I clean it up.

Thanks for looking, and I'll get that video on you-tube. Don't know why it wouldn't upload here, only 30 seconds.

Doug

 

[kuhncw]

Nice work, Doug. Thanks for the pictures of your setups.

Chuck

 

[gbritnell]

Great looking work. The head is really unique looking.

 

[Sprocket]

Got the videos of end rounding loaded End rounding on the rotary table - YouTube
finishing the ends - YouTube

Chuck and George, thanks for your comments.

Chuck - Set ups are funny, everyone sees a process differently, so there are many ways. I guess all that really matters is that you get where you want to go. I always feel like I'm making it up as I go along, but that's kind of fun.

A few more parts:
Valve adjusters are 1/4" hex, one end drilled for the valve lifter, the other threaded 5-40 for the valve.
I started with a round and milled enough for two hexes. The Hex collet holder made this pretty easy, back and forth lathe to mill. I turned the ends to size, drilled and tapped both ends, then split it in two and drilled the lifter hole


The last of these parts so far are the spring retainers. They mount on the valve stems , and compress the springs between them and the valve
housing.



The holes in these are tapped 2-56. I couldn't get my allen key to fit the recess in the set screw. finally figured a .050" key doesn't fit
in a 2-56 setscrew. Gotta order a smaller one. .035" I think. Won't really need it for a bit anyway.

Thanks for looking,

Doug

 

[Sprocket]

I finally got to brazing the crankcase. There are eight pieces in the bottom of the crankcase, and eight in the top. I needed to make a little fixture to hold the valve bodies aligned with the base of the water jacket, but it also worked to hold crankcase pieces together. The four sides and center piece are all bolted together, and the bolt heads ground off after brazing.


I had milled a shallow groove in the base plate to make it easier to align the box with the base, then clamped it in the fixture to attach the bolt rails, then flipped it over and brazed it to the base.


I was brazing from the inside and heating until it flowed through. the outside is pretty easy to clean up, and the inside doesn't really matter.
The top of the crankcase is pretty similar. I tried using White Out on parts of this one hoping for easier clean up.




The White Out helps, I guess. Not entirely sure I'm using it correctly, but it turns to chalk dust and brushes off.
No more room for pictures, I'll post more in a little while.
Thanks for looking,

Doug

 

[Sprocket]

The next step was to mill the mating surfaces. The bolt rails stick up a bit from the ends and center, and are milled down so all the parts are flush.

I also milled some from the outside to blend the brazes in and take off the overflow. The end mill has a little chamfer on the corner, not really a ball end, but it made fillets in the corners. (A corner chamfer end mill. I looked it up)


Still some cleaning up to do, then drill and tap the bolt rails so I can hook the top and bottom together and bore the holes for the bearings
and bearing caps.
I am amazed at the DRO. Finding more ways it makes stuff easier. these holes were drilled with the bolt circle function, and it worked slick. But I guess that's what it's supposed to do.
Anyway,
Thanks for looking,
Doug

 

[kuhncw]

Nice work on the brazing, Doug. What kind of torch were you using? Oxy/acetylene?

Chuck