When I first met Brice Adams he had been bitten by the Stationary Engine bug in lieu of the Steam Bug. I'm pleased to say that in 1999 Brice became the proud owner of a somewhat derelict, but operational Huber Traction Engine No. 8213. Brice has started the long and arduous task or restoring this pocket version of a traction engine.
Just after I published this article, Brice offered some comments and corrected some mistakes on my part - thanks.
Comment from Brice: When I got it it was one piece of rust. It had to be dragged on and off a roll-back truck to get it home.
The boiler was repaired by replacing the upper and lower super-heater flues. All the piping has been replaced and the cross-head pump valve body was missing. All the breeching was rebuilt/replaced.
I'd like to say that I've helped him, but the most I've done so far is scrape the grease off a part number on the motion gear and tried to work out how the cross-head is adjusted (seems this particular Huber has no wedges, hence no adjustment - can anyone shed any light on this?).
The Huber actually looks much worse than it is, the metal is very well preserved with a nice patina of surface rust which is protecting the metal underneath from the elements. The boiler is sound and has passed a hydrostatic test meaning it is safe to operate within the parameters set by the boiler examiner. I think the boiler has been certified to 150 pounds and Brice operates the engine at 100.
Update: This engine is no longer with Brice and looks considerably different... read the article.
Huber No. 8213 seen from the motion side. The motion gear visible from this side contains the cross-head in question. From this angle the Huber is reminiscent of a CASE design with the small eccentric fly-wheel instead of the more traditional crank shaft found in most European and Australian designs. Other American influences on the design are the off centre motion, most European and Australian designs have the motion squarely in the centre driving the crank shaft (much the same as an automotive crankshaft). Undoubtable this design is easier to make which probably helped its propagation throughout American designs of the time. From what I have seen only Avery followed the European tradition.
This is the off or flywheel side of the Huber. You can clearly see the drive gears inside the flywheel, on the side of the engine and within the rear wheels. Both wheels are driven. Differential drive is provided by a spur gear differential in the "Compensating Gear". The large gear in front of the right rear wheel. Bull gears can be seen on both rear drive wheels. [Ed: Thanks for the correction from Brice on this paragraph, I initially thought only one of the wheels was driven.]
|The Huber appears to be designed for one man operation. The footplate is too small for two people to comfortably work. The location of the throttle, clutch lever, and other controls immediately above the steering wheel fits in with this thinking.
Brice offered the following note:
A further noticeable difference which is quite uncommon is the return flue meaning that the chimney is at the rear of the engine just in front of the fire box. The hot gases from the fire pass through a large central tube "fire flue" of 25" dia rear and 22" dia in front within the boiler space to the "combustion chamber" at the front of the engine where those gases then pass back through several 14 x 3" flues, again still within the boiler space to the smoke box (breeching) in the rear of the engine and eventually out the chimney. Normally the chimney and smoke box would be found at the front of the engine. This would be another problematic feature with this engine as the gases in the return path would have much less heat and would probably drop much of their soot within the flue tubes especially when the fire gets going during heavy work requiring more frequent cleaning, fortunately as Brice points out:
Cleaning the flues is easily done from the rear by removing the doors from the smoke box.
|The Huber has a traditional fly ball governor driven by a 1" belt. Normally this would have been leather, but Brice's red nylon snatch cord will do a pretty good job short term. The governor is responsible for two things: keeping the engine in check so it does over speed and damage itself; and ensuring the engine runs at a fairly constant speed when working. The fly-ball weights are hinged and connected to a central rod which controls a valve within the body of the valve at the base of the unit. When the unit is stationary the valve is fully open, as the unit increases in speed the fly-balls lift causing the valve to close part or all the way reducing the amount of steam making its way to the engine.
If the engine is working driving say a saw-mill with a flat belt. The saw mill has to run at a constant speed. The operator would set the throttle of the engine slightly over the speed required by the mill. when there is no log the engine is only idling so is running a little fast, but the governor is holding the speed at the throttle setting. When a log comes into the mill and the blade starts its cut, the horsepower (work) required to turn the blade dramatically increases and the engine starts to slow down, at this moment the fly-balls spin slower making the steam valve open allowing more steam to the engine which in turn speeds up, once back at speed the fly-balls will lift again and the steam flow is reduced. This helps maintain the even speed throughout both idling and working hard. Effectively the fly-ball governor is changing the throttle settings with the operator having to deal with it.
|This shot of the flywheel clearly shows the friction clutch within the flywheel itself. This clutch controls the power transfer to the driving gears which drive the wheels.|
|The gears or drive motion transfer the power from the flywheel to the driving wheels of the tractor. These gears are responsible for the clanking rumbling sound you hear from a moving traction engine. The rest of the clutch can also be seen (it is the only painted part).|
|This shot shows a surprising feature considering the age of this engine. The main drive gear within the rear wheel has a spring arrangement. This helps to absorb the bumps of the road and the changes in motion when starting and stopping the engine making the unit smoother and less jarring to drive.
The bull gear bearing is rigidly mounted to the rear axle and the the springs allow the rear wheel to be independently sprung with a vertical motion of about 5". This feature was dropped about 1906, shortly after this engine was produced. I think it was cost cutting.
|Here we can see the motion of the engine, the cylinder block, the motion slide, cross head and connecting rod. Inside the cylinder block the piston is controlled by admitting steam and forcing the piston back and forth using valves. The in-and-out motion of the piston rod has to be translated into the in-and-out-up-and-down motion at the eccentric (or crankshaft on other designs) while still keeping the piston rod exactly horizontal. This job is done by the cross-head and connecting rod. The cross-head sits with the motion slide and slides back and forth as it is pushed and pulled by the piston rod. The connecting rod is fixed to the cross-head with a bearing so that at that end it is free to move up-and-down, at the other end it is fixed to the eccentric. When the piston moves, the eccentric turns transferring the engine power to the drive gears.
The cross head only moves horizontally, it does not move vertically unless there is some wear in the cross-head or guides - this would be noticed as a knocking sound when the engine is running. When such problem is noticed, the operator would normally adjust the wedges in the cross-head to compensate. This is where Brice' problem lies, this cross-head does not have wedges. The parts book for the engine shows wedges for the same part number. Possibly this is an earlier version of the cross-head which did not have wedges and they were added during later retrofit which this tractor did not receive.
|Another untraditional aspect of this engine's design is the location of the water tank on a platform in front of the combustion chamber. A small access panel is directly under the tank to allow cleaning of ashes from the combustion chamber and to allow extra air into the combustion chamber under full power operation to aid with combustion of gasses pulled off the fire by a full draft.|
|Immediately under the water tank platform can be seen the small access hatch for the combustion chamber mentioned in the last section.
The steering mechanism is the traditional worm gear roll with a chain which is attached at both ends of the front axle. When the worm gear turns it pulls in chain on one side and releases it on the other. The steering wheel can be seen in the backhead shot above. The unit does not appear to have power steering.