Review : Makita AC310H / Portable High-Pressure Air Compressor

The Makita AC320H is a delightful product for its elegant design, small form factor, lower noise levels

The Makita AC310H portable air compressor could be the best jobsite pneumatic supply for high-pressure nailers. The robust roll cage is true to the Makita legacy of super-tough engineering for the professional market. How does the compact Makita AC310H air compressor fare in a hardworking environment? Our review finds the answers.

Pneumatic nailers have long been the tool of choice for construction contractors. The problem many of us face is finding a reliable air compressor that can supply  high-pressure nailers without downtime. A jobsite air compressor needs to be compact and lightweight. It has to be as tough as it gets. These machines tend to be bashed about quite a bit. Providing the power needed, with a high amperage is another great advantage. On a jobsite, electrical supply may limited to a generator. Being able to use the compressor with a regular 15A 120V power supply can help a lot.

In many ways, Makita has hit the nail on the head with the AC310H portable air compressor. Some have an issue with the weight, just short of 80-pounds. This is certainly not ideal when you’re lugging the Makita from your truck to a jobsite and back again. There are lighter options from other brands. I’m not sure that the heavyweight design is all bad news though.

The wonderful roll cage that protects the Makita AC310H air compressor from damage is made from aluminum. This is obviously not what makes it heavier than many other products of the same size. Those pounds are concentrated in the engine, super-powerful pump, and tank. This means a lot of heavy-duty metal components. Surely this can’t be a bad thing?

TECH SPECS ► Makita AC310H	UPC Code : 088381-096928
Maximum Horsepower : 2½ hp	Maximum Pressure : 400 PSI
Running Horsepower : 1.9 hp	Net Weight : 79.4 lb
Performance (40 PSI) : 3.7 CFM	Pump Type : Oil-Free
Performance (90 PSI) : 3.6 CFM	Power Type : Electric
Performance (300 PSI) : 2.7 CFM	Shipping Weight : 88.16 lbs.

I reckon, long after many other air compressors have rusted away, the Makita AC310H will probably be chugging along merrily, with the type of reliability we’ve come to expect from the brand. My experience of using Makita tools, for many years, is that they just keep doing the job, day after day, year after year. They can endure more punishment than most. That’s important when you’re investing in professional-grade tools. Considering what a heavy-duty air compressor costs, you want to get your money’s worth over many years of hard work.

As it is, there are not many portable air compressors that deliver the pressure that the Makita AC310H does, with the same amazing recovery rate. Not to mention, as quietly or efficiently. For a portable air compressor to run high-pressure nailers, I doubt that you’ll find any better.

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REVIEW : Makita AC310H

Well-protected with a comprehensive roll cage and kick plate. Better through design is why Makita products are so good, consistently.

FEATURES :

• Dual capacity: two universal couplers for conventional nailers (3.6 CFM at 90 PSI) and two couplers for high pressure nailers (2.7 CFM at 300 PSI)
• Low amp draw reduces incidences of tripped breakers and voltage drop during start-ups
• Efficient dual-head (2 stage) pump provides faster recovery time and improved performance
• Makita High Pressure compressor technology delivers 400 PSI capacity for the next generation of high pressure nailers
• Pump runs at lower RPM (1,720) resulting in lower noise and improved pump durability
• Four-pole induction motor for increased efficiency and added durability
• Oil-less pump designed for maintenance-free operation
• High pressure 1.6 gallon tank provides the same capacity as a conventional 5 gallon tank at 120 PSI
• Large rubberized bumpers for added durability
• Roll cage and kick plate construction to withstand extreme jobsite environments
• Large regulator knobs for easier adjustments

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Standard Equipment :

• 2x regular pressure universal couplers
• 2x high pressure couplers

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High Power, Low Amps

Makita has done quite a superb job of maximizing the power derived from the 2.5 HP (1,500W) electric motor. Able to run on a conventional 15A outlet, the Makita AC310H can almost compete with larger 5-gallon air compressors.

The secret behind all this power is the highly efficient 4-pole induction motor. The motor runs at a pretty impressive 1,750 RPM and is remarkably quiet. No official noise levels have been published, but unofficial sources rate the Makita AC310H at around 90dBA. Not exactly whisper quiet, but certainly much less noise than any conventional air compressor.

Two-Stage Pump

All that power is transferred directly to a 2-stage, dual piston pump. This an oil-free pump which means reduced maintenance. Ordinarily, I’m not the biggest fan of oil-free pumps. Actually, these pumps are not oil-free, they just have oil for life. This means the pump is only god for as long as the oil remains inside the pump and maintains its viscosity.

For a compressor that is expected to last for many years, it is usually better to top up the oil and replace if needed. Unless, of course, the pump is designed to run cooler and is perfectly sealed. I think Makita has accomplished both these requirements with absolute perfection.

Despite my preference for a compressor that allows me to add oil, I’m prepared to give the Makita AC310H the benefit of the doubt. All those extra pounds that make this beast a drag when it comes to portability, are evidence that this machine is made to last. I certainly haven’t heard any complaints regarding oil leaks or overheating.

I have, however, read a few bad customer reviews, complaining about air leaks. This is not an inherent fault in the product design. Air leaks on the tank are rare. None the less, some guys have received Makita compressors that simply won’t reach maximum pressure, straight out the box.

This is a quality control issue that probably needs to be addressed. Any number of reasons can account for out-of-box air pressure loss. It could be a faulty pressure relief valve, damaged O-rings on the fittings, or simply bad workmanship in the assembly process. I can’t say which of these factory defects those unlucky customers experienced.

In the end, a certain amount of manufacturing error is unavoidable. It happens, even with the best of brands. One wouldn’t expect this to be a regular issue with a top brand like Makita, and it isn’t. Those few who have had the disappointment of a brand new air compressor that doesn’t do the job, would have sent it back under warranty.

Makita service, in my experience, is about the best there is. They also offer a 30-day money back guarantee if you’re not 100% satisfied with your purchase. I know it’s a hassle to send a faulty product back and wait for it to be repaired. Ideally, this should not happen. Unfortunately, it does. Though, this is not the norm when it comes to Makita air compressors. I stand by the brand and so do most who have been using Makita power tools for many years.

High Performance

Assuming you receive your Makita AC310H air compressor in good working order, I can pretty much guarantee that you won’t be disappointed.

The tank isn’t that large at all, 1.6 gallons. Yet, Makita claim that their high pressure technology means the 1.6 gallon AC310H can compare to a conventional 5-gallon air compressor at 120 Psi. I think this is a bit of an exaggeration.

Here are the recovery rate specs for the Makita AC310H:

• SCFM at 40 PSIG: 3.7
• SCFM at 90 PSIG: 3.6
• SCFM at 300 PSIG: 2.7

Tank pressure is maintained between 330 PSIG (cut-in pressure) and 400 PSIG (cut-out) pressure. The maximum high-pressure outlet is regulated at 375 PSIG, low pressure is at a maximum of 130 PSIG.

By my calculations (using the Makita AN610AH nail gun), you should be able to achieve approximately 50 nails per minute at 250 PSIG. Probably a little less than 40 times per minute at 320 PSIG. Really good for a compressor of this size. This is one of very few compact air compressors that have the grunt to drive large nails into hard material without a problem.

You can obviously use several low-pressure nails at the same time, without losing pressure.  

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— Using the Makita AC310H

I like the practical, super durable design of the Makita AC310H. The aluminum tubing frame protects the machinery from damage. It has plenty of rubber, serving as protection bumpers and handle grips. This adds some ease when lugging the Makita around. Thick rubber feet at the base also eliminate vibration.

The all-metal control panel is also protected by the frame and is angled for the easiest access and maximum visibility of the gauges when in use. Incorporated into this panel are 2 X  low-pressure outlets (MAX 0.83 MPA or 120 Psi) and 2 X high-pressure outlets (2.26 MPA or 327 Psi). There is a high-quality pressure gauge for each of these outlets. You can monitor both high-pressure and low-pressure air supply at all times. It also has a third pressure gauge in the center, displaying the tank pressure. Two dials control the outlet air pressure – one for the two low-pressure outlets, and one for the two high-pressure outlets.

The horizontally mounted “hotdog” style pressurized tank has an easy to use drain valve at the bottom. A lever at the side of the machine is used to turn it on or off.

Makita supply amazing high-pressure hoses, but these are quite expensive. I feel that these hoses are worth the price, considering the quality. Though you can probably find hoses as good, or at least almost as good, a little cheaper.

Quick coupler fittings can be a bit of a problem. The low-pressure outlets use a universal ¼” coupler. The couplers supplied by Makita are of the highest quality standard and are, as one would expect, rather pricey. It’s easy enough to buy aftermarket fittings for the LP outlets. The high-pressure fittings are not as easy. They are not a standard size and are not commonly available. You’ll most probably have to use the more expensive Makita fittings for the HP outlets.

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Conclusion / Is the Makita AC310H Right for You?

The Makita AC310H has been met with much enthusiasm from contractors and framers who like the advantage of high-pressure nailers. HP pneumatic nailers are the best, being more compact and generally easier to use. They allow you to work much faster, especially when working with harder materials.

It has not all been praise and accolades though. A few problems with quality control have resulted in the Makita AC310H receiving some pretty nasty customer reviews. There are also those who are not so impressed with the fact that you are almost obliged to purchase the unique high-pressure fittings at a premium set by Makita. This is not exactly a cheap brand.

Overall, the Makita has received very good reviews, an average of 4-stars on Amazon is evidence of this. Had it not been for the 1-star reviews, given by disappointed customers who received faulty compressors, this customer rating would be much higher.

I base my conclusion of Makita AC310H, when the machine is received in good working order. This would be the vast majority of occurrences. While factory defects are never welcome, they are not a true reflection of the product design or general quality. An abnormal defect can be repaired, and it won’t cost you, that’s what the warranty is for. With this in mind, I genuinely believe the Makita AC310H deserves 4½ stars.

The reason why I’m not willing to give them 5-stars is because of the expensive high-pressure fittings. I know that if you want the best, you should be prepared to pay for it. Though, we should have the option to decide which fittings we choose to buy. I never like it when a brand tries to force us to buy their accessories.

I also think the guys and girls at Makita might want to pay some attention to their quality control. As one of the more expensive brands, with a reputation for excellence, we don’t expect faulty products to arrive on our doorstep. I’ve never experienced this from Makita. I’ve always been hugely impressed with the quality of their tools, and the service I’ve received. There are others, it seems, that aren’t as enthusiastic about the products they received, and this cannot be a good thing for the brand.

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Tips / Advice — Buying a Portable High-Pressure Air Compressor

Choosing the best air compressor is all about the required pressure and the volume of air needed to keep your tools working without interruption. If the storage tank and recovery rate don’t meet your requirements, you end up waiting for the tank to re-pressurize before you can continue working.

My general rule is to buy the biggest, most powerful air compressor you can afford. Start by gathering the important information. The pressure rating (Psi) for all the pneumatic tools you expect to be using at any given time. List this, along with the CFM rating for each tool. Ideally, you want the CFM capability for your air compressor to be equivalent to the total of all the tools combined, plus 30% – 50%. This will allow for any oversight, possible leaks, and give you the option to upgrade your pneumatic tools in the future. You never know what tools you will be using in few years. It’s highly probable that your CFM requirements will increase over time.

That’s easily said when you’re buying a shop air compressor. You have the space for a large machine and it’s not that complicated to install a dedicated, high-amp supply for a powerful air compressor. Since you won’t readily be moving the air compressor, weight is not a real issue. When portability becomes a priority, you need to put more thought into your decision. It often requires some compromise.

When you start using high-pressure pneumatic tools, the decision between down time (waiting for the compressor to regain pressure) vs portability becomes much more complicated. Most air tools operate between 40 Psi (low-pressure) and 90 Psi (high pressure). This means that air compressor manufacturers generally supply machines that deliver a maximum pressure of 100 to 130 Psi at the tank. A higher tank pressure helps maintain working pressure at the outlets.

When we start looking at tools like high-pressure nail guns, we enter a completely different ball game. Your pressure requirement becomes more than three times what you would need for most conventional high-pressure pneumatic tools, about 360 Psi – 400 Psi.

The difference between supplying 120 Psi maximum air pressure and around 400 Psi, means re-engineering just about every component. To safely maintain this pressure, the storage tank needs to proportionally stronger. This means a much heavier tank, with thicker walls. The pump, electric motor, valves, and fittings also need to be stronger and, therefore, heavier.

The Makita AC310H is a perfect example of increased weight for higher pressure. It weighs about twice as much as an equivalent sized air compressor rated at 120 Psi maximum pressure and has a pretty small tank. This means it will out-perform other portable air compressors at a conventional (± 120 Psi) maximum pressure. When you’re using the maximum pressure for a high-pressure nailer, it might not be ideal for all situations.

A powerful high-pressure pneumatic nailer can require an ideal recovery rate of around 3 SCFM at 300 PSIG. The Makita AC310H is arguably the best compact high-pressure air compressor. Yet, it does not fully meet this requirement. It only produces 2.7 SCFM at 300 Psi. What does this mean when using the machine?

In most cases, you won’t really be inconvenienced by the less than ideal recovery rate. You may be working particularly fast at times. If, for example, you’re blasting nails at a rate of 1 per second at maximum pressure, you’ll only be able to drive about 30 nails before the compressor can’t keep up with you. Fortunately, we seldom work at this pace. You might drive up to 10 nails in rapid succession. Then you will invariably have to move, fetch something, or make some sort of measurement, before continuing. This will give the compressor time to recover.

This means that if one person is using a high-pressure nailer, it’s unlikely that you’ll be inconvenienced by long recovery times. When you have two people working at the same time, your chances of downtime increases. Even then, it’s not that likely that both people will be working at exactly the same rate. Chances are, one will stop working for a while, then the other. Most of the time, it should work out fine. Though, the faster you work, the greater the chance that you may end up waiting for the air compressor to recover from time to time.   

In the end, you need to consider the payoff between easy portability and efficient working times. Naturally, a rugged machine is always the best for a busy construction site. A 120V power requirement, without a high startup current, can be important. This is especially relevant if you regularly rely on generator power or don’t always have access to an electric outlet that can supply more than 15 or 20 amps.