Setting up shop air and power

In a few days my Doosan DNM 5700 will finally show up to the new shop. I need to be ready to hook it up to air and power so the install guys can do their thing. This will be the only machine in the shop for a while, and I'm not running 24/7 production.

The machine pre-install document says it needs 9cfm at 80 psi. I don't think the shop has any 240v outlets, but there are plenty of 120v outlets. I'm tempted to get a Harbor Freight compressor like this:
21 gal. 2-1/2 HP 125 PSI Cast Iron Vertical Air Compressor
or this
6 Gallon Air Compressor - 2 Stage, 5 HP, 165 PSI

and a dryer like this

Compressed Air Dryer - Save on this Compressed Air Dryer


I don't know if the smaller compressor is good enough with capacity. I hope the DNM 5700 doesn't consume 5 cubic feet of air per minute just for the spindle air purge.......my thought is that as long as the compressor has a tank full of air well over 80psi, then the intermittent draw from the machine for tool changes wouldn't be a problem. Am I wrong? I don't plan on using the machines air blast through the spindle continuously.

The larger compressor would handle it, but it's a lot more expensive and I would have to get an electrician to put in a 240v outlet.

What do you guys recommend?

I would just wire up a 220v outlet but if not possible you can just wore two of the 120v compressors in different circuits. Do get the extended warranty though they are harbor freight after all.

I would also just get a couple air filters don’t think you really need an air dryer I may be wrong though.


Btw how are the lathes going so far?

If you're lucky the Harbor Freight compressor should get you through the month until your screw compressor arrives. Then when it dies you can try to get your money back. Those things are really designed for occasional use.

I actually like HF for stuff that I need to use super-infrequently, things that if it wasn't cheap I wouldn't buy at all. An air compressor isn't that. Compressed air is the lifeblood of a shop. If you don't have air it doesn't matter how fancy your tools are, you ain't running. Get a decent one. Equally important, get a QUIET one.

I've been very happy with this one as my baby compressor, and I've gone through more than a few of these things. I used to be a contractor on the side back in my younger years.

Makita MAC7 Big Bore 2. HP Air Compressor - Hot Dog Tank Air Compressors - Amazon.com

A month?
Hah!
From the link:

Air delivery: 5.8 CFM @ 40 PSI, 4.7 CFM @ 90 PSI

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No more need to be said.

Generic Default said:

What do you guys recommend?

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Kaiser Air Tower, but you're looking at $7k. Super quiet, totally integrated (compressor/tank/dryer), as reliable as a compressor can be, very slick.

But since I don't have that kind of money? Step up a little bit from Harbor Freight and look at California Air Tools:

California Air Tools

They are *extremely* quiet, very reliable, well supported, and very reasonably priced. Yes, it is WAY more than the Harbor Freight, but on the other hand? It'll give you an easy 2-3 years of service, and do so very very quietly in the corner of your shop, no fuss. Only thing I would add is an air line + muffler for the auto drain valve system. It makes a big racket for about 1 second every time the compressor kicks on and is super annoying. Easy to quiet that down though.

From a previous thread Kaesar had a very good run time

https://www.practicalmachinist.com/vb/general/kaeser-compressor-normal-life-353128/

So go once with quality and you'll like it ever more , buy crap and you will hate while its there and when its gone.

Quick story on the little dirt cheap HF compressors...

My big compressor shit the bed, fried the motor.. So I fire up the little craftsman backup... Not
enough air to run everything (it actually was, just running too high of a pressure).. So I go get
one of those 2.5hp HF POS's linked above.. And then the Craftsman died too..

So I ran the whole shop on that 2.5hp POS, and then one day it wouldn't make good pressure anymore.. Ran
down and got another one.. Another 9 months and the second one started not making good pressure and running
too much.. So I ran down and got qty 2 of the 2hp 8gallon ones (same head as the 2.5hp 21 gallon)...

Then I cracked into them to see what was wrong.. The reed valves crack, and the head "gasket" fries.. A .012
feeler gage for the valve and some .005 STEEL shim stock for a new head gasket, and they work great.. Dial
the cut off back to 110-115 psi and they come up to pressure real quick, and that's filling all of the air lines,
and 40+ gallons of tank, running 3 mills and an air hog of a lathe on one POS compressor...

I do fire up a second compressor when I want to use an air blast..

I've had a new motor for the big compressor sitting here for the past 2 and a half years. Its actually sitting
on top of the compressor, I just haven't finished installing it yet (I need to make an adaptor plate). Going
to the smaller compressor with lower pressure, I dropped my electric bill by over $150 a month, so I haven't been
overly motivated to get the big one going again...

So, 4 HF compressors cost me just a tick more than the new motor for the big compressor, and I've saved $150 a month
in electricity. Absolutely sucks when I pull out the air tools (which isn't often), and even worse on the rare
occasion that I need the sand blaster... But just one of those POS's runs all the machines just fine, with just the
mills running, averages 9 minutes off, 2 minutes on...

One of these days, I'll get the big one going again.. I'm going to leave the tank where it is, and move the compressor
head somewhere where I don't have to hear it.. I'm going to run it at a MUCH lower pressure than before, probably
90-110 psi, and then wire in a second pressure switch for about 140 for when I want to sandblast, (Who am I kidding,
nobody WANTS to sand blast) or use some air tools...

In conclusion. I didn't need as much air as I thought I did, I also didn't need as much pressure as I thought I did,
and air is EXPENSIVE!!!! When you are running a little compressor, you will chase down and fix every air leak in the
shop... For the $$, I've been very impressed with the cheap HF compressors.



Back to the OP. I would highly suggest figuring out how to run your own wiring and put in your own outlets. Its
really pretty simple, and its not hard to do it right.

I would limit my exposure to HF to holding my middle finger out the window as I drive by. Invest in some decent equipment and you'll never regret it.

I looked at the air dryer a while back. Almost gave it a try, but the reviews on HF's site were shockingly horrible. I couldn't help notice that HF deleted all the negative reviews from their site.

It looks like you spend a decent $$$ in a nice machine... I would buy a minimum decent compressor with a few extra capacity. You don't know when you will need it.

I also only use the compressor for the machine, but I have an extra outlet in the wall that it comes very handy. For example when I have to remove the coolant from the machine.

If you're in a budget, and you don't mind the noise, I will look to the 60-gallon single stage from Quincy. I believe is 3.5HP. It was my first compressor and it never let me down.

When I moved to my new shop, I treated myself with a Kaeser Airtower. I have a nice Hankinson HT dryer that I don't use anymore, that I'm willing to let go for a good price. If you're interested send me a PM.

At first i thought you were kidding. I just hope if you go with HF air setup the facking thing dies on its first day. That would be a lesson for you.

Generic Default said:

What do you guys recommend?

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That you get your head examined? Lol. j/k- If you are just wanting to get through the installation day, those are fine, and the big one might be okay as a backup and a second dry receiver. But you can't possibly want to actually run production off one of those things?

How much did you pay for the machine? It's getting 3 phase power from somewhere- pull a 10/4 SO cord off that 3 phase and put a 30 amp plug on it. Get a 5hp integrated screw compressor and tuck it in the corner and be done with it. Add a second 80 gallon dry receiver close to the mill. This will let the screw run longer per cycle so the oil stays warm, and it will cut down the start/stop cycles.

The screw compressor will be quiet, it will only cycle a few times an hour for a few minutes at a time.

Doesn't matter you aren't running 24/7- you want to run continuous for a full shift? And have air to blow off the table between parts? Maybe run a burr gun? And not be getting constant low air pressure alarms?

That's a really nice new machine, you don't want to feed it crappy air.

I would buy a used Quincy off craigslist before I stuck a new HF POS in the shop.

So in post #8 Bob gives his actual experience with them (an HF brand) but guys still insist you are a moron for thinking it... go figure.

gkoenig said:

But since I don't have that kind of money? Step up a little bit from Harbor Freight and look at California Air Tools:

California Air Tools

They are *extremely* quiet, very reliable, well supported, and very reasonably priced. Yes, it is WAY more than the Harbor Freight, but on the other hand? It'll give you an easy 2-3 years of service, and do so very very quietly in the corner of your shop, no fuss.

Click to expand...

I would steer clear of California Air. I had a 2 HP for a year or two, when the only need I had was to push the stock feed plunger in my CNC lathe. Essentially 0 CFM requirement, just maintain some pressure.

Then I got the Speedio ...

The California Air lasted about 1 month, then would no longer pump up to shut-down pressure. I got into the pump to see if there was anything I could do, and found that they are a complete POS internally, and in no way built for any sort of sustained use. Besides, you'd need more than one of them to make your 9 CFM.

One other thing -- unless it is a screw compressor that is built to run continuously, you really should get a compressor that is like 2x your expected steady-state requirement, to give the poor thing a chance to rest between cycles.

Regards.

Mike

Mike1974 said:

So in post #8 Bob gives his actual experience with them (an HF brand) but guys still insist you are a moron for thinking it... go figure.

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When I read the OP, I assumed he was just yanking our chain. Seriously.

I think that Doosan will get about 5 minutes into cycle and throw a low air pressure alarm. But I might be wrong. I'm pretty sure that if that 2-1/2 HP compressor is the one, it will be running the entire time the spindle is turning. It doesn't take any time at all to pull a 21 gallon tank from 125 psi to 90 or whatever the kick-on pressure is, and the compressor is only putting out half the air the machine wants.

I read Bob's post, and if it works for him that's great. I think since he went around and fixed all his air leaks after going with the HF compressor, that his electrical usage when he goes back to the real compressor will be a lot less than it was.

I have a 7.5 hp screw compressor, and 2 x 80 gallon dry receivers in addition to the integral 53 gallon wet tank on the compressor. The compressor starts 2 or 3 times an hour, and runs for 6-8 minutes- just enough to keep the oil at temp. Doesn't cost much to run that way.

I can't fathom the idea that someone would spend 80K+ on a new VMC and then pair it with the cheapest air compressor known to man. My mind doesn't work that way. I wouldn't buy 4 cheap compressors instead of repairing a real one either. Hell, I don't even have the space to store the dead bodies.

But that's just me. I want to spend my time making parts, not dorking around with air compressors. My view is that the OP is being penny-wise and pound-foolish if he is really going to put one of those compressors in his new shop.

I got a 5hp Quincy and size 25 air dryer, same brand. Both seem very good. I had a 15 gallon dewalt that would run a lot to power my small VMC.. it died a couple months later. You don't need huge, but advice from experienced people (lots posted above) is don't skimp on your compressor. If you really can't spend the 2-3k, maybe get this one: link

Your install guy should be able to back off your purge air if it seems excessive.

[edit] I used a dessicant air dryer for a while before I got the dryer: link I could probably sell it to you as it's sitting around in my shop now.

[edit2] Also, don't run weenie air lines to your machine. They will restrict flow and can set off low air alarms unnecessarily.

No 240 outlets? How are you planning to power your machine? If you're limited to running 120V you're going to be very limited in what equipment you can get into.

I picked my up at northern tool. Took back roads.. good times. I should have brought a hammer and left the crate with them.

So far every favorable post about a specific piston compressor gets contradicted by someone else saying it's junk it it broke quickly.

The reason I suggested the HF compressors is because there's a store less than 5 miles from my shop, and the smaller compressor only weighs 100 pounds so I can wheel it into the back of my car and plug it into the shop wall outlet without a hassle.

It sounds like the best solution in the long term is to get a big screw compressor with extra storage tanks close to the VMC. Nobody has mentioned drying the air yet, I thought that was necessary. If I were going to run a bunch of machines all day every day then I wouldn't hesitate to buy an integrated screw compressor for the whole shop, but since I'm just running one VMC intermittently I thought it makes sense to buy something less expensive that doesn't cost loads of money just to idle most of the time.


EDIT;

CosmosK, I just typed all of the above stuff before I saw your post. That Quincy is well within my reasonable price range, runs on the voltage I have, and supplies enough air for the machines rated need.

CosmosK is the MVP of this thread so far. Thanks!

When you start running "production" you'll soon see the need for an air dryer. I never got any moisture out of my blowgun when I started my gig out of my garage for the first couple years. When you start filling up a 20 gallon tank umpteen times a day (instead of once or twice) you'll see. You get a spray of water vapor coming out after a few hours. It will corrode stuff quickly. You don't want that going into your VMC's valve block and you don't want that going into your spindle purge which is designed to keep moisture/coolant out. Good luck.

So if HF moves to another location, are you going to move your shop also?

Generic Default said:

The reason I suggested the HF compressors is because there's a store less than 5 miles from my shop, and the smaller compressor only weighs 100 pounds so I can wheel it into the back of my car and plug it into the shop wall outlet without a hassle.

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Generic Default said:

So far every favorable post about a specific piston compressor gets contradicted by someone else saying it's junk it it broke quickly.

The reason I suggested the HF compressors is because there's a store less than 5 miles from my shop, and the smaller compressor only weighs 100 pounds so I can wheel it into the back of my car and plug it into the shop wall outlet without a hassle.

It sounds like the best solution in the long term is to get a big screw compressor with extra storage tanks close to the VMC. Nobody has mentioned drying the air yet, I thought that was necessary. If I were going to run a bunch of machines all day every day then I wouldn't hesitate to buy an integrated screw compressor for the whole shop, but since I'm just running one VMC intermittently I thought it makes sense to buy something less expensive that doesn't cost loads of money just to idle most of the time.

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I used to run 2 recips. One was a 5hp Quincy and the other one is a 7.5hp Speedaire. I usually only ran one at a time because I had it setup that one compressor fed the machines in the back of the shop and the other one fed the machines in the front of the shop.

The bad thing was that if I was at the wrong end of the shop I had no pressure in my air hoses, so if I needed to blow something off I had to walk all the way back to the other end of the shop. And if I had the lathe going and I was running a mill too, I had to run both compressors.

It doesn't matter if you get a recip or a screw. The machine doesn't care how the air is made. I replaced the 5hp Quincy with a 7.5 hp screw because I got sick of the recips banging away all the time. The screw is just SO much quieter there is no comparison. And they are more efficient- they make more cfm per hp than a recip.

When I put in the screw I tied everything together, so I never run the Speedaire anymore. It's just a storage tank now. But if the screw goes down, I can fire up the recip and keep running parts.

I added the second receiver so I could get the cycles more to my liking on the screw. It was pumping up too fast, I don't want it to run for 2 minutes, 10 times an hour. I want it to run for 10 minutes, 2 times an hour! It's better for the compressor and my electric bill.

If you can't afford a screw compressor, buy a good recip. Minimum 5hp, minimum 60 gallon tank. A quality used is better than a new cheapo. I see decent 5hp recips on CL all the time for ~$400. You can add a new ASME rated 60 gallon receiver for about $300. Putting a receiver close to the machine gets rid of the pressure drop when the compressor is at the other end of the shop.

Air Compressors & Accessories | Air Compressor Tanks, Parts & Accessories | Campbell Hausfeld Air Receiver Surge Tank AR823, Vertical, 6 Gal. | B99194 - GlobalIndustrial.com

That little 2hp portable is NOT going to be idle when your Doosan is running. It's going to run constantly. 26 gallons, turns on at 110 and shuts off at 135. That is not a lot of air. On-off, On-off, On-off. All day long. That'sif it even shuts off at all...

It might get you by for a while, but it will burn up with that kind of usage. I "grantee" you.

Unless you are in the desert, get an air dryer. Or your air hoses will be pressure washers.

That Hankinson mentioned previously in this thread is a quality unit. If it's the 25cfm model, it will be good for up to a 7.5hp screw compressor.

HP gives you cfm, storage capacity determines how often it cycles. You want to find the right balance. You want your compressor to supply more air than your machine needs, so the compressor can rest a little bit. Your machine wants 9.8 cfm at 90psi? I would be looking at compressors that put out 50% more than that. Whether recip or screw doesn't really matter but screws are a lot nicer to work around for the noise.

Screws are more expensive to maintain. The separator and filter elements are expensive, and the oil is $100/gallon. You have to do it every year no matter how many hours you run. The tradeoff is the much better working environment when you don't have to listen to the damn compressor all the time.

BTW, congrats on the Doosan. That's a nice machine, I'm jealous.