High End Recip Compressor Advise Needed

[Mickey_D]

I do mostly CNC work in the shop and pneumatic tool changers and brakes (and leaks in the machines) take around 5 to 10 CFM whenever a job is running. When I started out I ran off of my 10 year old Porter Cable (Devilbiss) 10CFM 60 gallon compressor for a couple of years until it smoked a motor in the middle of a job. I did an emergency replacement with a 3HP Ingersoll 60 gallon unit and quickly learned that today's Ingersolls are not the same as the old ones. After the pump was replaced twice under warranty and the motor once by me, I got a 5HP Champion 60 gallon to replace it. I also plumbed in a mystery 3HP 3PH asian compressor that I got at an auction for something like $10 to use as an emergency backup unit. During the last three years I have had more downtime related to compressor failures or dicking around with upgrades than anything else.

I looked into switching to a rotary screw unit about a year ago and the sales guy said that I either had to run it continues and vent air (and suffer high electric bills) or let it cycle and have a greatly reduced life span from cycling and not keeping the oil temperature up. Work is getting busy enough that I am looking at adding another mill or two but I am totally out of space in the garage and no room to build, so it looks like renting more space is the only way to expand (besides putting a cnc in the dining room). So that I am not totally out of business for the duration of the move, I am planning to build out a new shop with all new (at least to me) equipment, get it up and making parts, and then merge the equipment from the existing shop in. So that leaves me looking for another compressor in the true 7.5HP range (about the limit you can run on single phase). New 7.5HP Champions and Quincy's seem to run in the $4K range but used ones come up from time to time in the $1K range for a good one. Any opinions on Champion vs. Quincy (never seen a QR-25 around here, just the reed valve Air Master series)? Any other newer reliable American units to keep an eye out for? I don't want to start a war about the Chinese import pumps, but my opinion about their quality control and casting skills is not very high.

 

[bmwpower]

From what I've seen from Quincy and thru visiting a local shop that fixes them, I'd go with Quincy. If you can't afford a new one, find a used one and rebuild it.

Other possibilities:

http://www.saylor-beall.com/

Make this guy an offer and swap a 7.5HP motor on there:
http://cgi.ebay.com/10-HP-Air-Compr...emQQptZLH_DefaultDomain_0?hash=item359f1dd98d

Or just go with a QT-7.5 instead:
http://www.tptools.com/p/2904,91_Quincy-Pro-and-Max-Series.html

 

[rsanter]

if you look at the rotary screw compressors, look at getting one that is VFD so that it will automatically reduce RPM to feed the demand at the time and will save energy in the process. for a shop with varying air demands, you can save up to about 70% on energy costs with the VFD unit

bob

 

[the spyder]

We ran 2 IR rotary screws at the CMM/CNC shop I worked at. The main 10hp unit ran 4 CNC's and 6 CMM machines. All with air bearings and toolchangers/brakes. It ran constantly. We had 10 breakdowns I can recall over 3 yeras, most were due to the tight as owner not doing service. At least the entire building was plumbed with copper.

I really cant recommend the IR's, as we had 3 total. 1 IR30 blew a head, 1 7.5hp Rotary screw- First in the NW- blew oil in to the lines, 1 10hp Rotary Screw kept having sealing issues on the screw. Blew out seals constantly. IR did nothing.

 

[Mickey_D]

There is no way I am touching Ingersoll again. The service guy who came out to change the pumps said that the reason that I was having so much fun was that they were making the smaller recips in India now, and my experience with things made in India makes me wish I had upgraded to the no-name Chinese brand! The last time that I was in Tractor Supply I stopped and looked at their 7.5HP Ingersoll and it now had an Ingersoll branded motor that was very crude looking. It made a Leeson or Marathon motors look like Cadillacs. I may look again at a screw pump, I did not know that they had variable speed units. I would actually love to find a nice QR-25 that has been well taken care of, but they seem to be the holy grail of used compressors and are priced accordingly.

 

[Mickey O]

I worked at a place that had two large Quincy rotary screw compressors, the larger ones, 25 hp and 50 hp. I was the one that maintained them, not that there was much to do change filters and the separator occasionally. The only problem we ever had was with a heat exchanger (water cooled unit) on one unit took a **** and that was about the only down time in over three years. Excellent compressors, don't know about the other brands mentioned but I would definitely recommend Quincy.

 

[bmwpower]

Find a local Quincy service place and go talk to them. See if they have used units for sale that they will service.

 

[Charles (in GA)]

Curtis, Champion, Quincy, Saylor-Beall, Jennings (the stationary units from the old Emglo, think, Jenny steam cleaners).

Those are your top of the line reciprocating compressors.

You are doing this as a business, you gotta pay if you wanna play, as they say. You may end up with a mix of two undersize compressors for flexability, one rotary screw on a tank, and one reciprocating unit to pick up the slack when the demand gets too high for the screw unit.

Charles

 

[sberry]

I am certainly not up to speed with current compressors but have a Champ, 40 yrs with 1000's of hrs on it. Don't think I ever touch the motor but did put rod brg and rings in it once, at one point it had its fair share of cold starts which probably didn't help.
I think you are on the right track with a high end unit, a home hobby shop might not make much difference but where hundreds of hrs add up fast and downtime could be an problem as well as a comparison against the rest of the shop equipment cost is an issue it makes sense to invest in what keeps the rest of it running. I tend to want to buy that kind of thing new and get it over with, gives longest service life.

 

[sberry]

If I went used I might service it up front but I like new. This is similar to say a MIG welder. Buying a used simple stick I might go for at the right price but a MIG I like to buy new especially if I intended to run the **** out of it. All new gun, liner, all the switches, relays, motors, etc, lots of parts. Same with a comp, new motor, new controls, pump, valves and tank. Like anything mechanical **** happens but at least you are not stuck working on a dilapidated pc of junk with multiple possible issues.

 

[rsanter]

at work we have 2 ATLAS-COPCO rotary screw compressors
one is the modulating and the other is the variable speed.

bob

 

[GeorgiaHybrid]

My vote is for a Quincy QR-25 model 325 (5 HP) or 340 (7.5 HP).

I might be a little biased though..... I have a 325 and love it. It's quiet, turns a low rpm, has an oil pump and spin off oil filter (pressurized bearings instead of splash lubed) and the valves can be serviced without pulling the head if required.

 

[kartracer55]

Check out Kaeser rotary screw compressors. Where I had worked, they were at least five years old, no problems and were run about sixty hours/ week.