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At home on the job site or in the workshop, the Ridgid Oil-Free compressor is powerful and tough.
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Ridgid #OF45150 Oil-Free Compressor

High-Volume Air Power

Text & Photos by Tom Hintz

   Air compressors are becoming standard fare in the home woodworking shop, driving nail guns, dust-busting blow nozzles and small finish sprayers if they have sufficient capacity. The Ridgid OF45150 Oil-Free Compressor handles these tasks with surprising ease, bringing exceptional power and capacity to the shop at a surprisingly low price.

Initial Impressions

  The word "tank" comes to mind - the olive drab military kind. Lifting the Ridgid OF45150 from its shipping carton was my first hint of how substantial this compressor is. From the heavy roll cage to the no-fooling-around motor to the air-squeezing cylinder, the Ridgid OF45150 is solid throughout. Within the tough construction is an array of features and capacities that make the Ridgid OF45150 as easy to use as it is powerful.

Oil-Free Compressor

Oil-Free compressors are not new, but they are powerful and reliable.
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A large cast cylinder block and head enclose a reciprocating piston fitted with long-wearing Teflon-coated rings that squeezes air within an extruded aluminum cylinder liner. This is a relatively old but highly efficient design that remains a favorite on high output air compressors.
               The oil-free design of the Ridgid OF45150 compressor reduces scheduled maintenance to draining the air tank daily and checking/cleaning the air filter weekly in most environments. The rest of the time it produces air for you to use.



The induction motor has plenty of power to drive the compressor.
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The Ridgid OF45150 is equipped with a serious-looking induction motor that features start and run capacitors. The motor runs on 120-volt (14.5-amp) house current which means using it in virtually any shop or job site will not trip circuit breakers all day.
               The motor boasts a peak of 3.25 HP and 1.8HP in normal running mode. The motor delivers 3450-RPM shaft speed to drive the compressor. Though I am generally suspect of horsepower claims, the Ridgid OF45150 gives no indication it lacks power.




   The combination of a piston-style compressor and the strong motor allow the Ridgid OF45150 to maintain 150 PSI of tank pressure and a whopping 6.2 SCFM (Standard Cubic Feet per Minute) at the outlet. This means the Ridgid OF45150 can supply adequate pressure and volume to meet the SCFM requirements of far more air tools than most compressors in its price range, and some costing far more.


Twin Tanks

Twin tanks keep the air coming smoothly. Note the arrow: That's the drain you "Say" you use every day!
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A dual storage tank system with a total capacity of 4.5 gallons lets tools work longer between compressor cycles. Air is pumped into the lower tank and then flows into the upper one through a tube. This not only helps trap moisture in the lower tank, the twin tanks function as a surge suppressing system to deliver more consistent line pressure to the tools.
               The lower tank has a finger-operated drain that should be used daily. Draining the air from the tank system helps eliminate moisture from the tanks and lines, prolonging the life of the entire assembly by reducing internal corrosion.


Controls and Instruments

The instrument panel keeps you informed about what is happening. A ratcheting dial give real-time pressure adjustments.
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The control panel features twin 2"-diameter gauges that read tank pressure (Right) and line pressure (Left). A ratcheting pressure adjusting knob allows fine adjustments of line pressure. The adjuster changes line pressure in real time, allowing the gauge to show the new setting without having to run a tool to purge the line first.
               An ASME safety valve automatically bleeds off tank pressure should it exceed 150 PSI. It also has a pull-ring that allows evacuating the majority of tank pressure at the end of the day before opening the tank-mounted drain. (The one you are supposed to use every day. Remember?)
   A pair of Universal Push-Style couplers access regulated air. Both couplers accept ¼" industrial and automotive-type plugs. The capacity of the Ridgid

Connecting lines is a one-handed operation.
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OF45150 means you actually can run more than one tool without out-pacing the air supply.
   A nice feature of these couplers is that they are normally "released" which means you can plug the air line into them with one hand. When the fitting is seated, the couple sleeve snaps forward, locking it in place.
   The On/Off switch is plumbed into the line that supplies the gauges and outlets. The On/Off switch also senses pressure drop, cycling the compressor and motor as needed to maintain 150 PSI in the storage tanks.

The 1"-diameter roll cage protects the unit and serves as a carry handle.
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Protective Cage


A protective "roll cage" made from 1"-diameter steel tubing protects the compressor from many of the hazards that could befall it in the shop or on the job site. The cage extends above and towards the center of the unit where a molded rubber handle makes carrying the 60+-pound unit easier.


In The Shop


   Being an oil-free, piston-type compressor, the Ridgid OF45150 is louder than my old pancake unit. We have to remember that the pancake compressor generates about 50 PSI less tank pressure (smaller tank also) and about ½ of the SCFM. Quite simply, it is not realistic to expect the Ridgid OF45150 or any other compressor to pump out this much capacity in silence. While the Ridgid OF45150 is a bit louder than my old pancake model, though not overly so, it runs far less often making the trade-off between volume and how often we have to hear it a wash. To help control sound, the Ridgid OF45150 comes with rubber vibration-absorbing feet installed that do a good job of preventing the machine from transferring sound to floors and walls.
   The pressure-generating capabilities of the Ridgid OF45150 really shine in the shop. The air demands of my largest finish nailer are insignificant to the Ridgid OF45150. Compared to my pancake compressor, the Ridgid OF45150 cycles on to replenish the tank roughly half as often with a much shorter run-time. Even when blasting dust off projects and machines with my favorite blowgun, the Ridgid OF45150 keeps up better with less running than its predecessor. We also found that even when operating two nail guns simultaneously, the Ridgid OF45150 just cruises along without breaking a sweat.

The Ridgid compressor kept up with all of the air tools I have in the shop, and far less than my old compressor in the process.
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   The key to the Ridgid OF45150 value lies in the 6.2 SCFM. A much larger range of air tools can be adequately powered with the Ridgid OF45150 at a cost more normally associated with lesser compressors. Factor in the solid design and construction and the Ridgid OF45150 becomes even more attractive.


   The Ridgid OF45150 air compressor offers solid, reliable construction and one of the highest SCFM rates in the business. Real-time pressure adjusting combined with dual, one-hand line fittings make the Ridgid OF45150 an easy tool to use. That combination of features insures more than enough capacity and flexibility to fill your current and future compressed air needs. With a current price of $259.00 (9-17-04), there might be enough money in the budget to buy another air tool to plug into it.
   If your shop is presently air-less or your compressor is begging for relief, check out the Ridgid OF45150 Oil-Free compressor at your local Home Depot or on line at www.homedepot.com.

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