Tell me about this old usa compressor I just bought.

Just got it today on craigslist for $50! Seems to work great. I need to replace the broken drain valve and also want to replace the oil fill and drain plugs as they're somewhat rounded.

This is pretty durn close
http://www.garagejournal.com/forum/attachment.php?attachmentid=58771&d=1269712281
http://www.garagejournal.com/forum/attachment.php?attachmentid=58772&d=1269712281

They were posted here but I don't remember who or where. I just bookmarked the pages.
Chuck

Good small compressor. Turn it up a little to get more pressure. Great for a small home shop. Ive had a few of those. Each has lasted 20+ years. Alittle to small for auto painting and sand blasting. Sold under many name brands.
Ron

Those are very nice little compressors, they usually run for a very long time. I had one nearly identical to yours, but it was 1 hp, it ran great for almost 30 years till the motor burned up. They are extemely quiet compressors, just dont expect to run a lot of air tools off it. I will always regret selling mine, but one day I will find another one.

One bit of advice, it will last longer if you add an unloader pressure switch to it. An unloader releaves the pressure from the compressor head after it reaches its set pressure and cycles off. All of the compressor heads from speedaire that I have seen with out an unloader, has an empty port right next to the copper line running to the tank. Also, if you wanted to raise the cut off pressure point, you will most likely have to change the safety valve depending on the age of your compressor. Most of them in the 1 to 2 hp range came with a 125 psi safety valve.

Here is a picture showing the line I ran for the unloader...



I have more pics if you need them

Sweet thanks for all the info guys! It does appear to have that unused port you mentioned bob. Where did you have that unloader line leading to on yours? Also, i'm guessing that to adjust the pressure cutoff, you open up the box that says "DO NOT ADJUST MAX PRESSURE" and tighten the screw with the spring on it? I think i'll normally run it at 120, but would like to have the option of cranking it up to 150 if I need to for things like crank pulleys if needed.

Just checked the safety valve, it says 150psi. Are they one time use? Or are they spring loaded and just release the excess pressure? Any ideas on how to figure out a build date on it? Also! The air filter looks pretty ridiculous, how should I go about upgrading it?

shampoop said:

Sweet thanks for all the info guys! It does appear to have that unused port you mentioned bob. Where did you have that unloader line leading to on yours? Also, i'm guessing that to adjust the pressure cutoff, you open up the box that says "DO NOT ADJUST MAX PRESSURE" and tighten the screw with the spring on it? I think i'll normally run it at 120, but would like to have the option of cranking it up to 150 if I need to for things like crank pulleys if needed.

Just checked the safety valve, it says 150psi. Are they one time use? Or are they spring loaded and just release the excess pressure? Any ideas on how to figure out a build date on it? Also! The air filter looks pretty ridiculous, how should I go about upgrading it?

Click to expand...

What psi does it cut off at? I have never seen one with a 150 psi safety valve, most were 125 psi with a cut off at 110 to 120 psi. A small single stage compressor would struggle to pump up to 150 psi and would take a very long time to do it. Also, you would want to stay at least 10 psi below the safety valve rating, as they tend to start leaking air before the rated psi is reached.

The safety valve is just a simple spring valve setup, it will reset itself if working properly when the psi gets below its psi rating. As for the air filter, if origiinal, might be a felt pad. I have not found an adapter to mount on one to use a modern air intake filter. I had a friend machine a plate of 1/4" steel with an npt bushing so that I could mount a new filter/intake.

Here are a few pics of the unloader line.

1/4" copper tubing, flare nut fitting on each end, ran underneath mounting plate to front of compressor to the pressure switch. I used wire wrap to keep the copper tubing from rubbing or rattling. It is easier to start from the front near the switch and run it back to the opening at the motor, gently bend the tubing up and out of the opening as you feed it from the front...


Here you can see it (from the front, and above) coming out from under neath the mounting plate going to the pressure switch...


Then making a 90 up to the bottom of the pressure switch, to another flare nut...


You will have to change the pressure switch to one with an unloader valve in it to do this. Could you post a pic of your pressure switch with the cover off?

Those were made for Grainger by Campbell Hausfeld, and are good quality units.

First picture shows what appears to be a load genie threaded into the fitting that is threaded into the tank. When the tank reaches full and the motor shuts off the load genie will vent, you can hear it.

It cuts off at around 120psi.

more pictures

milton v series coupler on the way along with the drain valve and a 25' flexzilla hose

You can change the entire cut of switch and pick your turn on and turn off psi for about $40. Instead of of guessing by tightening a spring you can buy a switch for the exact psi you want. I had I believe a 90psi on 125 psi off. I needed more volume than pressure so I went with (if i remember right) 80psi on 125psi off so it does not kick on as much since I only have a 20g tank. This way I can run a nail gun all day with out it running, since I have only 15 amps for the lights and outlets in the garage.

I know this is an old thread, but since it's been brought back anyway...

Major Ramifications said:

Those were made for Grainger by Campbell Hausfeld, and are good quality units.

Click to expand...

That makes sense. I have one with an eerily similar tank / manifold with what appears to be a CH pump and GE 1hp motor. Mine's unmarked as to manufacturer, but the crusty old gauge on it says Sears. I guess CH must have made 'em for Sears too.

I bought one back in '78 from Grainger , it still working great.