Some compressor related questions (basics)

[DerStig]

I'm very new to this so I would like ask some basic questions:

- Whats the reason why one would go with a 3/8" vs 1/4" air hose?
- If you get a 3/8" hose but the quick disconnects in the compressor are 1/4", is that a problem? Do they have converters and do you see any issues with 1/4" connector supplying air to 3/8" hose?
- I happen to have bought a 50ft hose (1/4") before but it has no reel. Lookong online literally all reels that retract automatically come with their own hose and the ones without hose is all manual. Does anyone know of any reels without a hose bit it retracts itself?
- This is more about the tools, before buying a compressor I was going to buy dewalt's new brushless impact wrench which puts over 1000 ft/lb of torque. I always thought air tools were stronger but I see that all air tools in that price range ($200-250) only provide 600 ft/lbs and if I want to go 1000 ft/lb not only I have to serious money for the tool but I most likely also need a 240v compressor with a lot of juice. What's the catch here in dewalt's tool? How can a battery powered unit put that much torque? Am I missing something fundemental with respect to how air tools work (wrenches)?

Thanks

 

[Boilerhouse]

3/8 hose will have a bit less resistance and should allow for a bit better flow than 1/4. Using 3/8 hose with 1/4 connectors is pretty much the standard set up and seems to work well - at least it does for me. Air impact guns use a fair bit of cfm, but do not typically operate for very long, therefore overall air use is not that high, like it would be for a sand blaster. You could probably get away with a 110 v compressor as long as your tank size is not too small and has sufficient reserve capacity. I have no experience with that particular Dewalt product, so I don't know how "real world" those numbers are.

 

[Z2V]

1/4" connectors on 3/8" hose is probably the most common for home shop/ garage use.
A battery powered tool is only as strong as the battery's charge and an air powered tool is only as strong as its air supply. The high torque ratings are needed more for removing fasteners than installing them. For real tight faster I usually break them loose with hand tools first and use a torque wrench for final installation. Lug nuts, head bolts, crank shaft dampers and the like are likely the highest torque items you will encounter in a home garage at around 100# give or take and definitely should be torqued by hand.
I have air, corded, and cordless 1/2" drive impacts. I use the Hilti cordless the most

 

[bdbecker]

You should be just fine running just about any tool in a home shop setting off of that 50' run of 1/4" hose. A 3/8" hose is less restrictive over distance than a 1/4" hose, but you will not notice the pressure drop unless you are running a really high consumption tool. Take a look at the table found on this page:

http://www.airtx.com/recommended-air-hoses.htm

A 3/4" impact is going to consume less than 10cfm, but let's assume that is the number. That means you'd only be getting 98.4psi out of your 1/4" hose instead of 99.4psi you'd get with 3/8" hose. Lucky for you, most air tools only need around 90psi to run correctly, so even if you bump the number up to 20cfm, your 1/4" hose is good for 91psi.

Basically, to sum it up, if you have a 110v compressor and aren't using more than 50' of hose, you really don't need anything bigger than 1/4" because your compressor is actually the weak link, not the hose. This coming from a guy who uses 3/8" hose with a compressor that can only produce 2.1cfm.

EDIT: I found this thread about the quick connect ratings... it looks like they would not be too much of a concern.

http://www.garagejournal.com/forum/showthread.php?t=116630

 

[md21722]

The above post is well meaning but incorrect except for the links.

1/4" is for nailers
3/8" is for most shop tools
1/2" is for 3/4" impacts and other big stuff

Problem with above post is that the Airtx link is referring to CFM as actual CFM, but many air tools use an "average CFM" rating. A 3/4" impact uses above 40 CFM while it's working.

 

[md21722]

You can buy air tools w 1000 ft lb in the $150's. HF Earthquake XT, NitroCat 1150, etc. The ones more powerful like the 2235 and nitrocat 1250 cost $250-300 because they're the newest and most powerful models.

Take back your 1/4" hose and buy a hose reel with 3/8" ...

 

[bdbecker]

The above post is well meaning but incorrect except for the links.

1/4" is for nailers
3/8" is for most shop tools
1/2" is for 3/4" impacts and other big stuff

Problem with above post is that the Airtx link is referring to CFM as actual CFM, but many air tools use an "average CFM" rating. A 3/4" impact uses above 40 CFM while it's working.

Wow, thank you for pointing that out - I never knew impacts pulled such a high cfm while operating. I stand corrected.

 

[sberry]

A 1/2 will lose 40# down 50 ft of 3/8, 75 down a 1/4. Agree with the above, probably closer to 50 with heavy 3/4 than 40 depending on supply and hose size.

 

[HotelMike]

- This is more about the tools, before buying a compressor I was going to buy dewalt's new brushless impact wrench which puts over 1000 ft/lb of torque. I always thought air tools were stronger but I see that all air tools in that price range ($200-250) only provide 600 ft/lbs and if I want to go 1000 ft/lb not only I have to serious money for the tool but I most likely also need a 240v compressor with a lot of juice. What's the catch here in dewalt's tool? How can a battery powered unit put that much torque? Am I missing something fundemental with respect to how air tools work (wrenches)?

There is more than just torque difference between air and battery impacts. Look at weight and size. A 1/2" brushless impact is fairly bulky compared to an air tool with similar torque rating. Then you go down the discussion of battery vs air tool lifespan and reliability but that is a whole other discussion

 

[laser3kw]

3/8 hose will have a bit less resistance and should allow for a bit better flow than 1/4

just a bit? your being modest.
just for perspective, if the actual inside diameter of the hose is a true 3/8", it will have 2.25 more cross sectional area than a 1/4" hose. Flow will be proportional to area.

here is a fun calculator to play with:
air hose flow calculator link

I remember seeing that 1/4" hose flows around 13 cfm and 3/8" flows around 30 cfm

 

[Schurkey]

1/4 air hose is a waste of time, money, effort, and enthusiasm.

 

[pmiranda]

As for finding a retracting reel without a hose, I doubt you will, since the retracting mechanism needs to have a given tension for a given weight of hose and the reel needs a certain size to accommodate a given o.d. and length of hose. So it's easier to size these two aspects of the reel with a known hose instead of a user-supplied one.

 

[DerStig]

Thanks for the answers. I guess I wasted money buying a 50 ft 1/4" hose without a reel

 

[pmiranda]

It'll come in handy some time. I use one to extend a line from my compressor out to edge of the driveway. The reel is great to mount on the ceiling for use in the garage.

 

[Schurkey]

Thanks for the answers. I guess I wasted money buying a 50 ft 1/4" hose without a reel

You'd have wasted a lot more money buying a 50 ft 1/4" hose WITH a reel.

Well, hell. You could fill tires with a 1/4" hose.

 

[Z2V]

You could dedicate the 1/4" hose to the pneumatic safety release on your lift and get a 3/8" for all your other needs.

 

[DerStig]

You could dedicate the 1/4" hose to the pneumatic safety release on your lift and get a 3/8" for all your other needs.

Thanks, I will probably do that.

 

[bixxjs]

Use your smaller line for small use tools and a bigger line for an impact wrench or a big grinder.
You should be able to get adaptors from any hardware store or eBay.