Metabo's SE 12-115 burnisher basically is a slow, variable-speed angle grinder with an extended spindle that fits accessory wheels up to 4-inches wide and 4 1/2-inches in diameter. A key on the spindle fits a groove in the wheels to provide a positive mechanical drive, and spacers of different widths are supplied for fitting wheels shorter than the spindle length. The tool body is held perpendicular to the direction of an angle grinder, and a large guard and handle assembly clamps to the head of the tool. This assembly can rotate for left- or right-handed grip, but the latter results in the burnisher moving toward the operator in an uncomfortable pushing action; it should be configured this way only to get into right-side corners or perhaps to switch the strain on the hands around during prolonged, low-resistance buffing. The motor rates at 10 amps and delivers speeds from 900 to 2,810 rpm. The tool weighs about 9 pounds with the wire brush, as shown.
For a more comprehensive review of this tool's abilities, we tested it in two separate capacities by different users, first with wood and then in a metal shop.
As the owner of a company dedicated to working with reclaimed barn wood, cleaning and texturing our finished products without removing original tool marks, surface patina, and other signs of character is very important. We produce a variety of timber and millwork products, including decorative trusses, post and beam components and assemblies, exterior siding and trim, garage door veneers, flooring, paneling, soffit boards, countertops, and stair components. Our wood comes from old Midwestern hay and dairy barns, dismantled "as is" with 100 or more years of rusty nails, dirt, imbedded grit, bird droppings, etc., and needs significant cleaning to be transformed into home-ready condition. Appearance is everything in our market; the cost of our products is significantly higher than standard construction materials.
Though originally designed for metal work, we found that the power, mobility, and variety of abrasive options of the burnisher worked well on wood surfaces. The Metabo excelled at removing dirt from the hand-hewn texture of timbers without abrading away axe marks and other original surface features. The wire-brush wheel removed dirt quickly and left a slight raised-grain texture. Its aggressiveness let us work faster than usual, saving time and money, and it seemed to wear very well. The grit-coated nylon brush is similar to what we're used to; it also cleaned surfaces well, leaving them smoother than the wire brush. The harder abrasive wheels and flap sanders seem better suited for smooth sanding, not our restorative finishing style.
One of the unique attributes of reclaimed wood is the unevenness of its surface, a result of twisting from drying over the years, dents and dings from a long-ago assembly and generations of use, and the weathering down of softer portions of the grain. The brushes' curved profiles and the unobstructed left ends let us follow contours and irregularities, -including mortise pockets and deep surface checks, -much better than other tools we've tried. Since we need to maneuver the angle of attack continuously and dig the brushes' corners into low spots, the supplied guide roller wasn't necessary or desirable, although it could come in handy when surfacing flatter boards or planks.
The burnisher's high power let us bear down when necessary to remove stubborn dirt or paint without the motor laboring. It is well-balanced, with the front handle mounted directly over and in line with the spindle. The tool weighs a bit more than we are used to, but the weight would be an issue only if it was used where its weight couldn't be partially supported by the work piece, for example, in an overhead application on a jobsite.
The fact that the wheels can be changed quickly without a tool is a real bonus. However, the small accessory wheel-retaining bolt and two loose washers you have to remove during this process are too easy to drop and lose in the sawdust. At least the washers could be captive, so I would only have to excavate one piece.
After sending the burnisher to a wood shop for a few weeks, I then tested its more common, intended use: decorative metal finishing. Metabo is a major player in metal fabricating and finishing tools, and they made the burnisher to do jobs that angle grinders aren't well-suited for. The slower motor speed and larger surface area of this tool's accessories make all the difference for decorative work. A variety of surface looks are attainable depending on the wheels used on the tool, from wire brushes to sanding to polishing. Popular "brushed" stainless steel finishes of different scratch depths are easily done with the rubber spindle with sandpaper sleeves or even with finer flap sander wheels. Smoother still are the results from the combination flap/nylon fiber (like a Scotch Brite pad) or the plain nylon-fiber wheels. For a polished finish, the nylon-fiber finish is followed up with three grades of buffing wheels and their specific polishing compounds. In a short time, stainless steel can go from its typical milky-white surface to a mirror polish in four steps, usually beginning with a 280 grit nylon-fiber wheel followed by all three buffing wheels.
When buffing, it helps to reduce the speed to a medium setting when applying the polishing compound so it doesn't fling off. Once it's applied evenly, I used the highest speed for polishing. When new, the buffing wheels are not exactly equal in diameter, so only about half of them contact the metal surface. To even them out, run them against a sharp metal edge on a scrap piece of material until they are even. Several buffing wheels fit on the spindle at once, and a spacer is needed to keep them on tight enough.
One problem I ran into was that the buffing pads at the outside end of the spindle didn't engage the spindle key and would free-spin when under load. Using the largest spacer and really cranking down on the assembly helped, but the free-spinning would still occur under heavy pressure.
Speaking of heavy pressure, I could really lean on this tool without slowing it down. Its electronic motor control keeps it at a constant rpm regardless of the load applied. Other benefits of this motor control are soft-starting, an overload shutoff with warning light, and accidental restart protection. This control also made the tool sound like it was shutting off every time it was lifted from the work surface, but I quickly got used to this.
The tool comes with a wide roller that can be attached to the guard to provide stability. Attaching the guard in the front position requires the tool to be held at an awkward forward angle, and puts the user in the path of the sanding grit and metal dust. However, with the roller at the rear of the guard, it allows very gentle application of the wheels to the work surface for enhanced control. This makes for both flatter finishing of the surface and more uniform wear of the accessory wheel because it won't let the corners dig in.
The roller generally wasn't helpful on wood or for coarser abrasives as it impeded the use of heavy pressure; it was hard to tell how much you were pushing on the roller versus the work. It also got in the way on small pieces as it often caught on the edges. It probably would be most useful on large surface finishes, such as on stainless steel wall panels or along lengthy railings.
I found two parts of the tool to be annoying. The spindle key was very loose and fell to the ground every time I removed a wheel. (CA glue to the rescue.) A more serious problem is the sharp corners of the guard attachment clamp that gouge the work when the burnisher is tilted or when a wheel wears down to about 3-inches in diameter. Filing its edges round or at least wrapping it with tape might save you from scratching your surface, but for a finishing tool, Metabo should have avoided this hazard by designing the clamp up higher toward the handle.
For a tool of such varied and unique uses, the manual has a noticeable lack of instruction. Detailed information about using specific accessories to achieve certain finishes, the speeds they are best suited for, and how to fit wheels on the tool using the different spacers would really help. For example, most accessories should be used as close as possible to the inside end of the spindle to reduce leverage on it and, therefore, wear on the bearings. So the spacers generally should be used on the outside end of the spindle; but for brushes and buffing wheels, which flare out when used, a spacer toward the inside will keep such accessories from abrading the inside end of the guard. A user's guide would save time and experimentation.
The Metabo SE 12-115 burnisher is a wonderfully versatile tool to use where typical sanders and grinders won't do the job. Whether removing a century of grime from a humble barn beam or bringing out a mirror polish on the stair railing to a penthouse, this one tool will do it all. After testing this tool on the job, I can say that the Metabo burnisher has easily earned a place among my other production tools. You just have to figure out how to use it first.
–Jon Hubert owns Singing Saw Woodworks, in Boulder, Colo.
–Senior editor Michael Springer conducted the metal work review.
Burnisher SE 12-115
[in kit with metal finishing accessories: $659]