Ball Hopper Monitor - Casting Project

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I think I am going to 3D print the parts for this engine, to give me a feel for the size of the parts, and to help me design and fit in the last bits and pieces.

I will include all of the bolt holes in all the parts, and make sure I don't have something like turned up a few days ago, ie: the spark plug going through the carburetor hole.

And I am out of time this year to progress on the design of this engine, so this will give me something to look at, and keep me thinking about this engine.

I feel like I don't really have a good enough understanding of the remaining parts to design them from photos, so this will allow me to fit the part to the print, such as the governor weight, rocker arm support, etc.

I will probably print along the parting lines, and check that while I am printing.

And a 3D print would make a nice table ornament too, but mainly it would give a good feel for the size of all the parts, and how they all fit together.

One thing I have noticed from looking at the photos from various 4hp Monitors, there is generally some variation that can be spotted in each photo, and it makes me think the Monitor engines evolved a bit over time.

One photo shows a handle built into the flywheel, to start the engine; which was common on some of the old engines.

Other photos show variations in the governor weight, and the governor weight stop.

And there are some variations in the sides of the crankcase/cylinder, at the crankcase/cylinder junction, for rod clearance.

I have seen the Lone Star 2hp drawings, but they are for a 2hp engine, which is different from a 4hp in many respects.
The Lone Star kit did not rigidly adhere to the full sized 2hp desin in some ways, although I still consider it a stellar kit, especially with regards to the quality of the castings.

I find it best just to look at photos of full sized 4hp Monitors, and reverse engineer from those.
This method gives the most accurate representation, although it takes some time and effort to design this way.

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I found a video that shows the trip mechanism for a 4hp full sized Ball Hopper Monitor, and I slowed it down to 10%.

This helps a lot in clarifying what is going on with the rocker arm, the governor weight mounted to the flywheel, and the "L-shaped" bracket that catches and holds up the end of the rocker arm.

After watching the video numerous times, I am going to re-write this description of what I think is happening below.

It has been difficult for me to get a good grasp of this mechanism and exactly how it catches and releases; when, and why.


As I recall on my dad's 7hp Galloway, if you tightened the governor spring, the engine would run faster, so perhaps the same would be true for the Ball Hopper Monitor ? (ie: tightening the governor weight spring would decrease the number of revolutions between the engine firing).

Looking at the Galloway governor weights, and their connection to the sliding collar on the crankshaft, I can more easily understand how that engine is latching.

The Ball Hopper Monitor latch mechanism is not nearly as obvious as the Galloway to me.

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Here is what I see happening on the Ball Hopper Monitor hit-and-miss mechanism.

There is a spring on the governor weight/arm that pulls it towards the flywheel hub.

The left end of the L-bracket rides on the green flange that is on the side of the governor weight.

As the engine rotates, assuming it is coasting down with the exhaust valve being held open, the cam rises every two flywheel revolutions and raises the end of the rocker arm.

When the end of the rocker arm is raised, the L-bracket is pulled to the right by the spring.
If the engine rpm gets low enough, the governor flange will be all the way down towards the center of the flywheel, the L-bracket will remain held to the right by the spring, and the rocker arm will move down with the cam, which closes the exhaust valve, and lets the intake/combustion/ignition/release sequence to happen.

Once the engine fires, the governor weight moves quickly outwards toward the flywheel rim, and its flange moves upwards/out from the flywheel center, the left end of the L-bracket moves upwards, which moves the detent to the left, and catches the end of the rocker arm, holding it up and holding the exhaust valve open until the slows down again enough to let the governor weight drop far to release the detent again.

It all happens so fast that it is tricky to understand when watching a full speed video.


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Note that the mass of the governor weight/arm times the distance from its center of mass to the crankshaft centerline equals the mass of the flywheel recess above it times the distance from its center of mass to the crankshaft centerline.

This is the excellent video of a 4hp Ball hopper Monitor that I have been looking for.

You can slow this video down, and see the hit-and-miss mechanism pretty well.

High resolution video too (1080p).

Does not really need to be slowed down he has it running so slowly. Plug moved to the front too. Sproket suggests it may have run with a Mag at some time too.
The cam in that video I don't think should be striking the end of the L-bracket, as it appears to be doing.
I think that is a misalignment issue.

And the spring should be connected to pull the L-bracket back towards the engine frame.

Looks like he drilled a hole for the priming cup too.
The priming cup is normally where he has the sparkplug, and the sparkplug is normally on the left side of the valve chamber.

It is a very nice running engine for sure.
He has it dialed in well.
You can see/hear it draw open the intake valve, and then hear it fire near TDC, and then hear when the exhaust valve opens, and compare that with the flywheel position.

Very nice video, and very helpful.

Looking through an old Baker catalog, there are both wood and cast iron sub bases listed in the repair parts schedule.

I can't find any photos of a cast iron sub-base for a Ball Hopper Monitor, so we will have to improvise, and imagine what that looked like.

Perhaps the horizontal engine bases will give a clue as to what the Ball Hopper cast base looked like.

I have a feeling the Ball Hopper cast sub-base was a crude representation of their wood base, with C-channel sections I would guess.

It appears that Baker created new engine designs, and then basically made minor changes to that design over the years.

Major design changes seem to have been saved for new engine models, such as the horizontal engines with their modern hemispherical combustion chambers and valve layout, and the "Little Pumpjack" engine, with its headless deisgn.

I have noticed that Honda tends to create motorcycle engine designs, and then use that same design for many years, sometimes in multiple motorcycle formats. It makes sense to put a lot of effort into getting an engine designed correctly in the initial design, so that changes do not have to be made during production.

There were a large number of engine manufacturers/engine designs in the early 1900's, and then a gradual consolidation into a few manufacturers with the more advanced higher rpm designs.

I suppose that is the natural progression with emerging technology such as gas engines.

Steam engines of the early 1900's were considered far superior to gasoline engines, as witnessed by the Mt. Washington Hill Climb by F.O. Stanley in 1899 in his Stanley Steam car; a feat that no gas engine of the time could even begin to approach.

Here is a link to the Mt. Washington climb:
The success of the Stanley Steamer with the Mt. Washington climb was directly related to the output capacity of the burner, and the surface area of the tubes in the boiler, as well as the significantly higher than generally considered normal operating pressure of 600 psi.
The Stanley motor design would almost be an afterthought.
The original Stanley Steam auto used an engine designed by Mason, and the Stanley brothers redesigned and refined the Mason design, but the Stanley engine had its roots in the Mason engine, and used the same basic format/layout as the Mason engine.
As I recall, the D-valves in a Stanley engine experienced heavy wear since they were unbalanced.
I have seen folks who still run Stanley's convert the cylinder to a piston-valve design, which eliminates the high-wear problem with higher steam pressure.

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After much consideration, I am going to make drawings and patterns for two scales of the Baker Ball Hopper Monitor.

I have decided to make a 1-off model at 1/2 scale, which will give 14" diameter flywheels, and an overall engine height of about 30 inches from the bottom of the flywheels to the top of the hopper cover.
These patterns will be 3D printed with single shrinkage factor, and smoothed, but kept in plastic form.

The second set of drawings and patterns will be for an engine with 10" flywheels, and I will use double shrinkage on these 3D printed patterns, and make permanent aluminum patterns.

I checked with Barney Kedrowski (the guy who provided me with photos of his 4hp Ball Hopper Monitor, which made this design possible), to get a second opinion, and he said "Go for it ! ".

So onwards we go with a 1/2 scale 4hp Ball Hopper Monitor.

I will have to get creative with the pours, and may have to use two furnaces (I have two), and do a double simutaneous pour on the larger parts.

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Its too cold to do any foundry work (as if I had the time anyway), and so I will blog along with parting lines.

These are the parting lines that I know have to occur.

I see one overhang on the boss inside of the water hopper, and that could be fixed by filling behind the bosses away from the direction of pull.

I need to clean up the inside of the frame/cylinder, and get that smoothed out.

I do have a limited quantity of nickle-mag, or so I am told that is what I have.
I have not used it, but could use it to make the crankshaft in ductile iron.
Once it is gone, I don't have any more.
Someone sent me a small quantity of nickle-mag, but no supplier for restock.

The cylinder head does not have any draft on the sides, but I am going to try to pull it without draft angle, and I think I can get away with it on a part that is not too deep.

It should be noted that none of these pattern halves include machining allowances yet.

Normally bolt holes and keyways are drilled/cut after the casting work is complete.

As I recall, the valve chamber is not symmetrical about the parting line; it projects further in one direction than the other, which is no problem.

The muffler halves don't need a parting line.

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