New to me compressor

wannabewoodworker · Post by **wannabewoodworker** » Sun Apr 03, 2011 11:14 pm

Well I have needed a bigger compressor for a while. I have a 3 hp Craftsman that I have used for many years and it still works perfectly but it has never had the power to run most of my air tools from my dealership days. So I have been on the look out for a replacement. I have been constantly keeping my eye on Craigslist and finally I found one. It is a Craftsman Professional 7 hp 60 gallon vertical tank and has a max PSI rating of 175. The CFM rating is 10 at 90 psi and has a max of 12.35. The guy I bought it from said he ran all of his tools with it and had no problems with it keeping up as well as a sand blast cabinet with no issues. So I am pretty excited to get it hooked up. It is 220V so I have to add a 220 circuit in the garage this week to be able to run it. I upgraded the electrical in the garage a while back ago to 100 amp service and have enough room in the box to add the 220 breaker so it should be pretty straight forward and i should have it running in a couple of days. A compressor is something I just could not live without in the garage and I use it all the time so this should be a really nice addition to my dungeon. Oh I only paid $300 for the compressor and from what I could gather that was a pretty nice deal considering the prices of the other used machines and what the new ones go for.

garys · Post by **garys** » Mon Apr 04, 2011 11:56 am

Keep in mind that the 7hp rating isn't true horsepower. It is peak horsepower which doesn't mean anything in the real world. It is a sales gimmick. The 10cfm @90psi tells you that it is really about a 3hp compressor.

My shop compressor is a true 5hp compressor, and it makes 18.5cfm @ 100psi.

In the real world, you get 3-3.5 cfm per horsepower of motor.

But, at $300, it is a great deal.

damagi · Post by **damagi** » Mon Apr 04, 2011 12:53 pm

I snagged a craftsman pro 6hp 30gal 150psi unit from a guy at work for $160...now just need to get some air tools

dusty · Post by **dusty** » Mon Apr 04, 2011 1:30 pm

Gee, I feel deprived now. I have a 1.5hp, 4 gal that has been with me almost as long as the 1st Mark V and I thought it was doing great.

wannabewoodworker · Post by **wannabewoodworker** » Mon Apr 04, 2011 10:31 pm

garys wrote:Keep in mind that the 7hp rating isn't true horsepower. It is peak horsepower which doesn't mean anything in the real world. It is a sales gimmick. The 10cfm @90psi tells you that it is really about a 3hp compressor.

My shop compressor is a true 5hp compressor, and it makes 18.5cfm @ 100psi.

In the real world, you get 3-3.5 cfm per horsepower of motor.

But, at $300, it is a great deal.

Thanks Gary I knew all of that prior to purchasing this unit. I figured it would be a heck of a lot better than my 30 ga. 3 hp. 8 scfm/6scfm little compressor that would not keep up with the demand of the air tools I have. I got it all wired up tonight to a new 240 v. outlet I installed next to the main 100 amp. breaker box. It ran without issue and kept up with the demand although it did run constantly once the air was depleted to a certain psi. It is very loud compared to my smaller unit but it does have th oomph to run my tools now. I would have much preffered a unit like the one you have with 18-20 cfm but could not put that kind of dough together right now and this was a smokin' deal as far as I am concerned looking at what was available new/used. I am pretty happy with it and it will make things much more efficient when utilizing my air tools now.