Harbor Freight Tools that don't suck

[frugalangler]

So what I'm to believe it's that putting the 1/2" air line on helps the Earthquake XT impact and that the small diameter fittings do not set the limit on airflow that the impact sees it how it will perform.

My mind has trouble coming to terms with that. It feels like the system would be limited by the smallest diameter within the entire run.

I (and you're free to differ) believe there is an advantage to larger diameter line even if the inlet is smaller, in that the line is part of the 'tank' and puts a larger volume of storage closer to the tool, not a lot, but in burst operation a long line of small diameter can create more resistance than just a small restriction due to the storage effect, more air closer to tool w/ less restriction in line.

This might be something for a 'MythBuster' analysis LOL

 

[California]

So what I'm to believe it's that putting the 1/2" air line on helps the Earthquake XT impact and that the small diameter fittings do not set the limit on airflow that the impact sees it how it will perform.

My mind has trouble coming to terms with that. It feels like the system would be limited by the smallest diameter within the entire run.

I was considering busting some concrete to install 1/2 black pipe from the compressor up to the shop and then maintain flow with all the largest diameter fittings and lines that I could use within reason. The final problem is the inlet diameter of the impact itself, it's below that 1/2" size so my mind says that I could use a sewer pipe up to that point, but it can only flow what that impact inlet allows.

We need some engineer with practical training to come along and answer this definitely but what I've read is air is compressible so it just goes through small fittings at higher pressure and velocity, not losing much energy if the restriction isn't very long. Ok that's theory, as I understand it.

My experience installing the larger fitting in the photo was subjectively that the $19 HF impact wrench in the photo needed a huge amount of air. The larger fittings - at the compressor and at the tool - helped. But that impact wrench still struggled to remove old rusty lugnuts so I replaced it with the $75 Earthquake which doesn't empty the compressor tank as fast but has much more torque.

 

[aeblank]

Each fitting or length of hose has a loss associated. A foot of small hose isn't as bad as 10 foot. One small fitting isn't as bad as 2. A 45 isn't as bad as a 90. Etc.
The losses are additive. In fluids class, they always gave the loss factor, but in real life that info is impossible to find.

This is 'Murica, bigger is better. Haha.

 

[aczlan]

If you want to see how restrictive your current system is you can:
1. Get a quarter inch tee and a quarter inch rear mount pressure gauge.
2. Install them between the quick connect and the impact wrench.
3. Watch them while you're using the impact wrench on a stuck bolt or to tighten a bolt down.

The difference in pressure between the gauge at the impact wrench and the pressure at the tank (or pressure regulator) will tell you how much loss you have in the system and if you need to worry about it.
If for example you have 120 PSI at the regulator or tank and 90 PSI at the impact wrench while in use then you should be able to get the rated torque out of it without changing anything.

If you have at least 90 psi at the impact wrench with 120 PSI at the tank, I would not worry about upgrading your lines.

Aaron Z

 

[Threepoint]

I (and you're free to differ) believe there is an advantage to larger diameter line even if the inlet is smaller, in that the line is part of the 'tank' and puts a larger volume of storage closer to the tool, not a lot, but in burst operation a long line of small diameter can create more resistance than just a small restriction due to the storage effect, more air closer to tool w/ less restriction in line.

This might be something for a 'MythBuster' analysis LOL

I'm no engineer, but until one chimes in, I think the answer lies with two separate principles: (1) loss of energy due to friction against the walls of the hose or fitting, and (2) the Bernoulli Effect, which says that an increase in the speed of a fluid (either liquid or gas) through a constricted space is simultaneously accompanied by a decrease in the fluid's pressure, i.e., its potential energy.

Energy loss due to friction: The friction coefficient of the hose or fitting is affected by the size being used. Increasing the internal diameter of a hose or a fitting by just 25 percent (e.g., switching from 3/8" I.D. hose to 1/2" I.D.) nearly doubles the internal volume of air that the hose/fitting will handle (cfm) at a given pressure. So the airflow encounters less resistance per unit of volume, and there is less friction loss.

Energy loss due to the Bernoulli Effect: Assuming the compressor is delivering a constant psi, when the air encounters a restriction due to a smaller hose or the smaller orifice of a fitting, it will speed up. Because of the Bernoulli Effect (which derives directly from the principle of conservation of energy), the air pressure must simultaneously drop until past the restriction, reducing its potential energy to drive the pneumatic tool.



In the case of fittings, I've used the larger-style fittings linked to earlier (1/4 In. x 3/8 In. Automotive Series Coupler and Plug Kit 4 Pc) on 3/8" hoses for about 20 years, although mine came from Home Depot under, I think, the Campbell-Hausfeld brand. From experience, they make the higher-volume pneumatic tools work noticeably better. As California noted, the I.D. of the larger HF fittings is 7.5mm, vs 5mm for the standard. That's a full 50 percent increase!

I've never needed to go with 1/2" hose, and would be reluctant to do it because of the weight and stiffness. 3/8" hoses are cumbersome enough to handle. If I were removing lug nuts on heavy equipment all day, I would for sure!

 

[tjkubota93]

I don't know about a 1/2" impact, but I have seen first hand the effects of too small a hose on a 1" impact.

 

[newbury]

Curious if anyone has experience with the 21 gal compressors ( item no.'s #61454, 62803 , 69091). My old Porter Cable finally bit the dust after many years of service and 2 compressor rebuilds so I bought the above mentioned HF model the other day to replace it. I had to reset the motor 7 times before it would start so I could run it for the initial 1/2 hour break in. It is an oil lubricated compressor and it was 10 degrees F in the shop when I did the initial start up/ break in it but I have to say that my initial impression is pretty poor and would not expect the temps to effect start up. I did buy the 1 year ESP so whether it turns out OK or not, I am going to replace it before the service plan runs out- just really curious if anyone else has bought one and can give their impression?

I read a bit on another board and went with the 29 gallon.



Twice the cost but moderately quiet, plus a few more PSI.

 

[mike69440]

The batteries are slightly different. AvE on YouTube did some vidgeos (if you watch him, you'll get that) on it.

Love watching that AvE quy. Darn, I'm glad I did not buy those HF Drills.
However, he seamed to think a lot of the Earthquake stuff.

 

[sixdogs]

So, If I have 100' of 3/8" line rolled up on a reel with one end connected to my tank and the other connected to the impact wrench with standard small size fittings I will likely see a significant loss of pressure between the tank and wrench from loss along the way?

 

[crazyal]

I have a 1/2" airline with the larger quick connects (Milton brand) on my 1/2" impact and yes it makes a difference. An impact doesn't use a steady stream of air. A rush of air comes in, spins the motor, it then "hammers" the socket slowing the motor back down some. I don't think the user can tell that it's happening though. The air in the tank is really too far away to make an immediate impact on the impact wrench. So you are counting on the air stored up in the air line. The more that's there (a 1/2" hose has more volume than a 3/8" hose) the better. Also the bigger the restriction at the inlet of the gun the less volume in the relatively short period of time it has will get into the gun.