A new question about Pneumatic tools and such?

[TopCatGr58]

Hey there Folks,

Once again I come to the great trough of learning and beseech the masses to increase my knowledge base!

I first had a little pancake compressor, just a few gallons, then got an extra 10 gallon tank, but still didn't have the volume reserve to run the air tools I wanted to. I then got a 25 gallon system, supposed to get up to 120 psi, and flow IIRC 4-5 ft/sec. I have a good quality Goodyear 3/8" 50 foot long hose. I have 2 different 1/2" impact drivers wanting to use them for light duty like changing tires and such. However, it doesn't seem to have the ability to FLOW the volume needed to feed the drivers...I only get a few hits, 5-7 before it craps out, I have to wait for the pressure to build up in the line before using it again! While writing this I think I may have come up with the limiting factor being the regulator on it. I had it set/open to allow the maximum pressure, but I think it may not have large enough openings to allow the volume to flow as quickly as it needs to.

The Impact drivers actually stated that they should not be run at pressures over ~90 psi IIRC, but I can't recall the FPS rate they need, one is a basic HF unit, the other is a Campbell Hausfeld supposedly rated at like 250 ft/lbs torque.

Is the 3/8" line big enough to flow the volume of air these wrenches require or do I need to get 1/2"? I'm going to work with the regulator...it actually has 2 on there, one right on the tank, a second one that is part of a dehumidifier/oiler combo. I'm not using the oiler part.

Any other thoughts, suggestions, info would be appreciated.. ! I've been looking at possibly getting an ELECTRIC corded 110v 1/2" Impact Driver if I can't get these pneumatic ones to work. I could have sworn that the 25 gallon tank would have given me enough pressure/volume to drive these things!?

T.C.

[crazy steve]

...While writing this I think I may have come up with the limiting factor being the regulator on it. I had it set/open to allow the maximum pressure, but I think it may not have large enough openings to allow the volume to flow as quickly as it needs to.

Yep, the regulators on the smaller compressors don't always flow enough. As to the 90psi limit, I don't know that I'd worry about that. I run all my air tools directly off the tank (except for the spray gun and powder gun, I've got inline regulators for those), I've never had any problems. 4-5 CFM is very marginal for most air tools, but should be fine for an impact wrench or air ratchet where you don't have constant demand. And 3/8" hose is plenty...

I'm sure the regulator is the choke point.

[ManagerMike]

The 90psi ratings for useage and torque specs used by the manufacturures are based on 1/2" id hose (too bulky to work with) and usually 80 gallon storage capacity. Also stating a 90 psi max pressure rating allows them to designate any warranty null and void if it is used at any pressure/volume supply that actually makes the tool usefull.
My personel experience with air tools is that anything less than 150psi and a minimum of 20 gal storage will leave you with the impression that these tools are utterly useless (which at that point they truly are).
I've been in the auto/truck repair industry profesionally for more than a quarter century now, and have never worked in a facility that ran less than 175psi with at least 80 gallons of energy storage.
At the shop I currently manage we run at 175psi, 160 gallon storage, and 3/8" hose.

If the best you have available is 120psi and 25 gal, you would be better off using that for filling tires and, at the most, air ratchets. Air impact wrenches would be effectively useless.

[petejw]

running a shorter length of hose might help also. jat

[BA80]

Lose the regulator on the line TC. It'll choke down the flow.

Run tools straight off the tank then all you have to worry about is the compressor keeping up.

[fredintoon]

CFMs

Hi T.C.
you need a bigger compressor. At least 10 CFM. Set the pressure cut-off switch at 120psi and run the air tools straight off the tank.
That'll make your nuts go loose.

[natemoen]

Oh I miss they days when I had free reign and access to a pair of industrial 250psi compressors with 100% duty cycle and 15,000ish gallons of storage capacity. Had around 400 pneumatic pumps running 90psi and we could have them all running at once and you could still run all the tools you wanted and nothing would skip a beat! It was beautiful!

[DGXSER]

TC,

Yes, the CFM (not FPS) rating is important as well as what pressure it is at. The 4-5 CFM you stated is pretty typical for 1/2" impact gun @ 90 PSI. That is probably your worst case load, and you most likely will not run any simultaneous loads. Now, if you plan to run any disc sanders and cut-off tools or such, that would change the top end to more like 10-15 CFM. BTW, those CFM ratings already take into account the intermitent use of the tools.

3/8" line is not going to give you more than 1-2 PSI drop in that 50' length, so that should be fine.

Personally, I have an older Craftsman 20 gallon 175 PSI compressor. I looked but could not find the HP rating on it. It has a regulator on it, I use it all the time. It has yet to let me down with any compressed air need I have, and I can not recall the last time I waited on it to catch up with me.

The difference being the 175 PSI versus the 120 PSI. Alot of air gets shoved into that 20 gallon tank at 175 PSI.

You can try without the regulator, but I doubt that will actually help with running out of air. It will give each hit a little more torque, but use more air to do it. I would look into the components on your system to see if there is a reason it is limited to 120 PSI. The tank I am willing to bet is minimum 300 PSI rated. If you find the weak link and can easily replace it, you may be able to raise your storage up to 150-175 PSI.

[BA80]

I have to wait for the pressure to build up in the line before using it again! .

You can try without the regulator, but I doubt that will actually help with running out of air.

Running out of line pressure is different from running out of pressure all together.

[crazy steve]

...I would look into the components on your system to see if there is a reason it is limited to 120 PSI. The tank I am willing to bet is minimum 300 PSI rated. If you find the weak link and can easily replace it, you may be able to raise your storage up to 150-175 PSI.

The 300 psi rating on the tank is pretty standard. To bump up the system pressure, you'll need to replace the pressure switch. The problem here is the compressor rated for the higher pressure? You may end up with a compressor that never shuts off if it can't actually produce the higher pressure, and depending on it's design some won't produce it.

[DGXSER]

Greg, I meant system pressure. Obviously, if your line pressure is low, the tank pressure is low or your regulator is bad.

Steve, of course the switch is the change to let the coompressor try to make more pressure. I was suggesting to verify if all the opther compopnents are rated for the higher pressure. Yep, the compressor may not be able to do it, that is where the HP of the compressor comes in.

[BA80]

Greg, I meant system pressure. Obviously, if your line pressure is low, the tank pressure is low or your regulator is bad.

Obviously,he said LINE not system. Just sayin'.

[TopCatGr58]

Hey guys,

Thanks for the info. The tank is actually only a 21 gallon...my CRS again!
It's setup at the factory for only 115 psi cutoff, but it has a nice 3 HP motor, an oil style pump. At these pressures, it's rated for 4.9 cfm at 90 psi and 7 cfm at 40 psi. It's a Central Pneumatic model #94667, and I was able to find the pressure/cutoff adjustment procedure from a simple "NET" search.

I'll be taking 1 of the regulators out of the line, and reset the cutoff pressure and see how the tools perform, but I'm expecting them to work as designed with these "IMPROVEMENTS" thanks again to the collective wisdom here!!
I should be able to get my nuts off with ease then!

T.C.

[BA80]

TC, the regulator is only needed with certaian tools such as a paint gun and should only be used there. Air tools will run best without restriction.

At the shop our air compressors run around 150psi and if there is something that needs regulated pressure the regulator is added as needed at the line being used.

The regulator is unnesessary unless a specific tool, such as a paint sprayer, requires it. And then it is incorperated in the specific line.

[TopCatGr58]

Update!

Well, my B-I-L had a Sears regulator rated for 175 psi with 3/8" fittings vs. my wimpy chinese 1/4" ones, so I went to LOWES and got a few fittings to be able to put it on. My in line on/off valve broke, so I also had to pick up a new valve but they only had one with a 1/2" taper and 3/8" taper fittings, had to get several adapters to convert from taper tip to NPT threads, and down to 1/4" size. Got it all together, and found the adjuster for the pump shut off max pressure, was able to set to 140 psi. I couldn't go any higher because the SAFETY RELEASE valve blew open at 140 psi! I can probably get one rated at a higher level, but I decided to try it with just that for now.

Connected the 50 foot 3/8" line, the stronger Campbell/hausfeld impact gun, and tried it on my Sister In Law's tire lug nuts...she had a slow leak and I wanted to take the wheel off anyways to go get it patched. The Gun worked GREAT!!!!!! Torque, power, spin and air to spare!!! That's what I was expecting with the bigger tank, and now thanks to you all, I finally got the volume and power needed to run it! And this was WITH the regulator inline, but set for wide open full pressure. But I'll need it when I connect it to the Plasma cutter when needed.

T.C.