68 Futura:
There was a division of Brunner's assets or divisions. Brunner had been making refrigeration compressors and condensing units along with their air compressor line. When Brunner was sold off, Dunham-Bush, a maker of HVAC equipment, got the refrigeration compressor/condensing unit line from Brunner. The air compressor division was sold to C-P. When I worked up at the Hinkley Dam, on a Power Authority hydroelectric project, this was a bit North of Utica, NY. The nearest Power Authority facility is the 'Marcy Energy Control Center'. This is a hub for most of the major power transmission lines in NYS. One of the Power Authority men at Marcy had formerly worked at C-P in Utica. He had been in the 'milling department', and told me that C-P had taken over Brunner's plant. C-P had switched from compressor production to air tool production. Eventually, C-P moved that division out of Utica, NY and to somewhere down in the Southern states.
I also remember seeing an ancient Brunner air compressor when I was in college, about 1970. It was in the garage of an oldtimer in Connecticut. This Brunner compressor was tank mounted and had the original Brunner decals and nameplate with the Utica, NY location. I was drawn to this compressor because it was old enough to have a flat belt drive.
As for price, consider the times and what manufactured goods cost relative to a person's salary. In the 'teens and 'twenties, prices for things like electric coffee pots, electric waffle irons, vacuum cleaners, and radios were quite high when compared to working people's salaries in those years. While wages were low for factory workers, the methods of production (sand casting of many appliance parts vs die casting, and later, plastics), amount of hand labor or multiple machining operations needed to produce even small home appliances put the prices way up there. It was quite common for people to buy a radio (a major purchase back then and considered the height of luxury), or a vacuum cleaner (the old upright type) on 'time', making payments rather than coming in with all cash. Who would buy a vacuum cleaner on time today (unless maybe a Kirby or similar) ? Think of the cost of automobiles in relation to a person's salary. Ford was paying 5 dollars a day, and had to bring the price of the Model T down to about $375.00 to make it affordable (and attract buyers for a car which was rapidly obsoleted by the competitors). 5 bucks a day x 6 days a week x 52 weeks a years (who took vacations back then, let alone paid ones ?) = $1560.00 per year. Take out rent, food, and utility bills for electric and gas, take out streetcar fares to get to and from work, and the workers were left with not a whole lot.
On the other hand, take a professional or executive, or perhaps a foreman or supervisor in a plant. These people could buy cars more towards the higher end, cars like Buick or Olds or Nash. These people would have the means to buy not only the car, but own a home, and keep the car in a garage. In the garage would be the oil bottles, battery charger, and maybe an air compressor.
I agree that the price, in 1925, was high for the average homeowner. However, places like apartment buildings or 'apartment hotels' ( a common thing in the 20's), as well as parking garages would be the likely purchasers of this type compressor. I believe, in the Brunner advertising, the compressors are listed with recommendations as to size of compressor vs number of cars parked in the garage.
If we think in terms of what tools and equipment an automotive repair garage would have had in the 20's, my own belief is that they had no compressed air driven tools, and the car lifts used were cable/mechanical 'four post' lifts for the most part. An automotive repair garage might only use compressed air for inflating tires or blowing to clear debris or clogged fuel lines. Hence, a relatively small capacity air compressor might meet the needs of an automobile repair garage handily. As the use of air tools became common, along with air-over-oil hydraulic vehicle lifts, the compressor capacity had to increase. The market for the small packaged compressors like the OP posted would have dropped way off once the move to air tools and air-over-hydraulic lifts took hold.
I note that Brunner used a 'silent' pinion gear on the little packaged compressors. This was made of 'fabric reinforced phenolic' (aka "Micarta" or "Ryertek"). It was a common design for open spur gearing to quiet things down. My old Cincinnati-Bickford drill has the original GE 3 HP repulsion induction motor on it. Drive off the motor is made using a pinion made of reinforced phenolic, running on a cast iron bull gear. Nice, quiet drive. I like how Brunner built the tank mounted unit shown in some of the posts. They addressed the matter of 'short centers' between the motor and compressor by adding spring loaded idler pulleys to get more belt wrap. It is quite a thing to realize that everything was built so much heavier, with iron castings used quite often, requiring a lot more machining operations.
