Product Details

• Amazon Sales Rank: #4713 in Home Improvement
• Brand: Porter-Cable
• Model: 390K
• Released on: 2008-07-01
• Dimensions: 9.25" h x 15.38" w x 7.25" l, 6.34 pounds

Features

• 3.5 Amp EnduraTech motor for increased performance and durability
• Variable-speed, 7,000-to-12,000 OPM for optimal removal rate on a variety of materials; 3/32-inch orbit diameter
• Low-profile design reduces sander height by 31-percent for better control and finish
• Measures 4 x 5 x 12 inches and weighs 2.1 pounds
• Integrated dust port accepts 1- and 1-1/2-inch vacuum hoses; includes kit box

Amazon.com Product Description
Featuring a low center of gravity for a natural feel, the Porter-Cable 390K Five-Inch, Low-Profile Random-Orbit Sander Kit with Hook-and-Loop Pad is efficient and easy to control. Its powerful motor ensures robust, time-saving performance on a variety of woods, including red oak, pine, and poplar. An added bonus, the sander features integrated dust collection that keeps your workpiece clean, so you'll be sure to get the best results possible.

The Porter-Cable 390K Sander Kit with Hook-and-Loop Pad At a Glance: 3.5-Amp EnduraTech motor Low-profile design Electronic load control Variable-speed 7,000 - 12,000 OPM 3/32" orbit diameter Improved ergonomics

Low profile design and variable speed range facilitate otherwise difficult jobs.

Sander features a five-inch hook-and-loop pad with eight-hole pattern.

Low-Profile Design for Optimum Control
The 390K sets a new standard for palm-grip sanders. Its low-profile design is 31% shorter than the competition. This means superior control and finish, as well as comfortable handling on the job.

EnduraTech Motor for Increased Productivity
Equipped with a revolutionary 3.5-amp EnduraTech brushless motor, this sander has a variable speed range of 7,000 to 12,000 OPM for optimal removal rate on a variety of materials. And because the motor has 71% fewer wearable parts, it will last five to ten times longer than traditional motors, saving you money and boosting productivity in both the short and long term.

What's more, an electronic load-control feature monitors the RPM and maintains a constant operating speed for smooth sanding and 42% faster material removal. Also, the 390K saves you time with its innovative electronic motor brake, which reduces spin-down waiting by 73%.

A separate mechanical pad brake reduces free-spin--effectively putting an end to gouging, and a 3/32-inch orbit diameter means this sander can handle a range of materials with ease.

Portable and User Friendly
Complete with a rubber grip and measuring 4 x 5 x 12 inches (WxHxD) and weighing just 2.1 pounds, the 390K is comfortable, compact, and easy to handle and store.

For further convenience, an integrated dust port accepts 1.0 and 1.5-inch vacuum hoses for optimal dust collection. This makes your workspace cleaner and healthier and helps maintain good visibility of your workpiece.

What's in the Box
390K Random-Orbit Sander Kit; five-inch hook-and-loop pad with eight-hole pattern; rugged storage case; and user manual.

Customer Reviews

Excellent sander, but some shortcomings
Intrigued by the design, I purchased this sander. Overall, I am very pleased with it. Here are the pros and cons:

Pros: Lower center of gravity makes it a delight to use. Feels more natural, like a sanding block. This is a very, very powerful sander, and the constant response motor prevents the sander from bogging down with pressure--no matter how hard or soft you apply pressure to the workpiece, the power is always there. The quick stop feature is a great innovation--you don't need to wait for it to stop or use a "sander sitter". The benefit of all of this is that you get A LOT of sanding done in much less time, compared to other 5 inch orbital units (e.g. Bosch).

Cons: (reason for 4 stars and not 5) Two, that are greatly overshadowed by the PRO's above, but issues nonetheless. The biggest problem is the receptacle for dust collection. It only takes that stupid Porter Cable dust hose that is horribly inefficient due to the small size of the hose. The hose is functional and does suck up dust, but could be better. I had one of these hoses laying around from my biscuit cutter, but it is still a lousy design. Maybe I can Jimmy up some type of setup for a better hose with an adapter.

The next con is that the top of the unit is somewhat broad and a little difficult to "palm" without some hand fatigue, but I am getting used to it. This ergonomic shortcoming is somewhat compensated by less fatigue by the lower center of gravity, but not entirely. The more standard units have a smaller top that is easier to get your hand around.

I would definitely buy the item again. It is a very useful tool.

Rated 4 1/2 stars
I just received my orbital sander (Porter-Cable 390K) a few weeks ago. I bought this sander based on a review in one of the recent wood magazines. Removed it from the box, put some sandpaper on it and away I went. I sanded Oak, Pine and Popular. I used 80, 120, 150 and 220 grit sandpaper and was pleasantly pleased with the results. My biggest concern having my shop in the basement was dust. I've got three other orbital sanders and had to do all my sanding outside. But that is not the case any more. I tried the sander with the dust collector on and then with my Shop-Vac. The dust collection in the on board collector was very good just a small amount of dust left on the bench. For very small, short jobs I would use this method. For larger, longer jobs my Shop-Vac will be used, from what I could tell there was no dust left behind (in both cases if I wiped my hand a crossed the board and there was wood dust. The dust I was talking about was on the bench and in the air, boards have to be whipped clean with a tack cloth. This is one of the few electric tools that I can use the Shop-Vac 1¼ "hose with no adapters and it works like a champ. The noise is very low and the vibration was low also. I wear a medium glove (my fingers are a bit short of the ends) and I found this very comfortable to use. I had complete control and the low center of gravity made it very maneuverable. On high speed this was very aggressive, thus the advantages of speed control and a light touch. I would recommend this sander to all. Overall the only problems I see is the little dust left behind with the on board collection system and price (time will tell if the price was worth it). By the way my other sanders are in storage until I need to do sanding outside.

Definite improvement
This review comes about after 10 hrs of real world use of the new sander. The best new features are the quick spindown and the variable speed control. I'm a professional cabinetmaker, and I use the sander to sand between finish coats as well as typical usage. The low speed helps control burn through on flat surfaces and narrow edges using 320grit. The low profile and slight increase in power are the second best new features. The only thing I'm not crazy about is the width of the grip. I have an average hand size and it's a bit wide and not what I would call ergonomic. I would have also put the speed control in a easier to reach place, so that I could control the speed with the same hand that I'm sanding with. The ergonomics become more of an issue when a vacuum hose is hooked up to the sander. It's that little extra pull of weight that makes the job more tiring when your sanding for multiple hours. It's also worth noting that the sander vibrates less that the last version and is a couple of decibles quieter that the 333. I would have given five stars if the sander were more ergonomic.