Home Built Compressor

I've been looking to purchase a large compressor such as one of those with a 60 or 80 gallon tank so I could run air tools and do sand blasting. I had the the pump already, all I needed was a very large tank. The pump I found in the local dump about 25 years ago. It was made by Borg Warner. Talk about not throwing anything away. I believe it's from a dump truck. My Dad rebuilt it with new rings and gaskets. He was going to use it for his first compressor also. Until recently I had no tank. A neighbor of mine that is in the recycling hobby had this tank for about two years. I asked what he wanted for it. He told me nothing, just get it out of here, so I dragged it home. The end result is as you can see in the following pics. I hope that it has given you some ideas of your own.

	This is the beast. It's a twin cylinder pump from a 40's or 50's dump truck. I'll call this the back side. On the left side (opposite the pulley) is were the lube oil is piped into the crank bearing. The lube drain hole is in the crank base. At this angle it isn't to visible.
	I'll call this the front side. At the top is the pressure release valves that would open up at a set pressure and let the pump free wheel since you wouldn't shut the engine off once the proper pressure in the tank was reached. The two carriage bolts are were the air exits to the tank. Directly below that is the intake port. You'll also notice two holes in the head of the compressor. This is were the coolant lines were hooked up. The head is made of aluminum.
	I needed a way to pipe up the exhaust port. I shaped a piece of 1/4" brass the shape of the exhaust port seat and silver soldered a brass fitting to it. The fitting has this end flared and the other end was a pipe thread which I turned to a specific diameter to fit into the flat piece of brass. Holes for the mounting screws still need to be drilled.
	Almost a perfect fit. Now to get the mounting holes drilled.
	The pump has been temporarily welded on a 12" X 12" base plate. Holes were drilled and the plate was bolted to the tank frame. Also seen in this picture are the trunions I made to mount the pump to it's base. The compression fitting for the lube oil and the barbed fitting for the drain line are also very visible in this photo, as is the 3/4" hydraulic hose used to pipe the air to the tank.
	The only major purchase for this project was the 5HP 220Volt single phase motor. Tractor Supply supplied that. The plate the motor is mounted on is also 12" X 12". The slots in the tank frame were spaced 10" apart. I made four aluminum spacers that slide in the groves of the frame to keep the motor straight.
	Since I needed a motor to run a lube pump that would turn on before the pump and shut off after the pump shut off I made use of two pressure switches. The one furthest from the take actually controls the motor.
	This is the "lube station". I made up a bracket to hold the lube motor, pump and lube tank (not show yet). The motor is a 1/4 horse 120 volt motor. The pump is from an oil furnace. A bit of angle iron and a piece of aluminum mounted on MDF works fine for now. The fitting with the T handle is only temporary. A flared fitting will be added later. The bottom fitting is the inlet for the oil. The T handled fitting is in the outlet port.
	Over all view of the compressor. Not yet finished.
	This is how the compressor stands at the moment. It works fine with it's separate lube pump. As can be seen in the picture I'm using a plastic container as my oil reservoir. I just drilled a hole smaller than the fitting threads and screwed it into the plastic, no leaks. The return line is bigger and just comes in on a hole in top of the lid. The pressure line that goes to the crank bearings is 5/16" copper with single flared ends. I still need to add a water coolant system to it. The head of the compressor runs quite hot. I've got all the material together. All I need to do is assemble it.

UPDATE: It's been almost a year now that I've had the compressor in operation. (built in April 2004) It served me well for short use of air tools and such, but it fell a bit short when it came to do any sand blasting. Although the compressor had the pressure it just did not have the volume to keep up with the constant supply of air need to for sand blasting. I came across what I needed in a surplus catalog called the "Surplus Center". You can browse there on line catalog at "Surplus Center.Com".

When I looked at the variety of compressors I saw one that would do the job. Since I already had the tank and motor I needed to fit the compressor to it. The one that fit the bill is a model made by Schulz. It is a V-type twin stage 175 psi, 21 CFM model. In the pictures below you can see just what came with the compressor. At the time I purchased this item they had 7 of them left. Being a surplus store it is hard to tell if they will ever get this style in again.

Here's the new compressor shortly after I brought it home, still bolted to the shipping crate. Included with the compressor is a 5" pulley and a 16.5" pulley. Using a 3450 RPM 220 Volt motor results in a 1045 RPM at the compressor. Unfortunately I could not use the 5" pulley since it has a 1" bore and the motor I'm using has a 3/4" shaft. So in the mean time I'm using the 4" pulley that I had on the original setup. It gives me an RPM at the compressor of 836 RPM. Even at that speed the compress didn't run as long as the old would have to get to 135 PSI, the shut off point of the pressure switch.

Four new holes drilled in the mounting plate and a new belt and it was up in running in no time. Even the hose from the old setup was usable since it had 1/2" pipe fitting. Although it took two trips to the parts store to get the correct belt length. Now all I have to do is cut off the support I'd made for the lube motor and turn the compressor 90 degrees clockwise so the air will flow better. As it stands right now the large fly wheel - fan is only about 3" away from the wall and is not affording a good air flow to keep the compressor cool for longer durations of running time.

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