Veer off of Mass Ave onto Lowell Street in Arlington, take the first right on Mill Lane, walk a hundred yards and step back 150 years. That’s when  Old Schwamb Mill, custom oval frame manufactory began creating the most beautiful picture frames in the world, and where the original equipment still operates in its Civil War era building. My friend Bob and I happened by last Tuesday and enjoyed one of the most memorable tours of my life.

At one time seven mills operated along the Mill Brook, which originates in Arlington’s Great Meadow and parallels Massachusetts Avenue through Arlington Heights, Arlington Center, and East Arlington, before joining the Mystic River. These days, most of the mills are remembered only by the names of bulky condominium buildings, but the Old Schwamb Mill was saved from the wrecker’s ball and was listed on the National Register of Historic places in 1971. Today, it is a working museum, open to the public two days a week.

The Schwamb Mill has made oval picture frames – frames that now hang in the White House and Buckingham Palace – since 1864. It’s hard to know which is more impressive, the four rotating frame jigs that allow a craftsman to create beautiful molding profiles in perfect ellipses of any axial proportion, or Dave, the keeper of the mill for the past fifteen years who dropped everything he was doing to give us a leisurely tour.

The wood frame building is little changed since the Civil War. The rough floorboards, exposed columns and beams, though well maintained, have never been updated. The dark interior, highlighted by sharp light through six-over-six pane windows, is full of workbenches, profile templates, molding samples and well-worn hand tools. Along the south wall, where the natural light is strongest, three frame jigs are permanently bolted to the floors, ceilings, and walls, with cast iron supports. Belt and pulley systems turn the jigs. They were originally driven by water, then steam, and only recently by NStar.

Dave explains how the oval frame jigs work. The pulleys rotate a huge axle, maybe 10” in diameter, that spin a wide, flat plate. Two other iron plates are attached to this, at right angles to each other. They can be held at a fixed distance from each other yet slide independent of the main element. A large slab of wood is fixed to the outermost plate. When the main axle turns, the inner plate spins in a circle, but the outer plate, and the wood attached to it, spins in an ellipse, with the major and minor axes determined by the distance fixed between the two sliding plates. It’s ingenious and durable; the machines are more than a century old.

Oval picture frames are made from four pieces of hardwood, each one-quarter oval, that are rough cut into thick arcs but have precise finger joints. This rudimentary shape is back screwed to the jig. A heavy iron stand sits to the left of each jig, at the single precise height that is perpendicular to the frame at every point of the ellipse’s irregular turn. Dave pulls an overhead wooden lever the size of a paddle. The belts roll, the plates spin, the wood base and rough frame rotate in what appears to be a wobbly motion, but that movement is precise at the location of the chisel stand. Dave takes a chisel, and with steady hand lays it atop the stand. He gouges a clean, crisp line along the spinning oval.

It takes about eight hours to make a frame: two hours to cut the four pieces of hardwood into a rough oval and finger-joint glue the edges; an hour to set up the jig once the glue is dry; two to three hours to shape and sand; a final hour for an oil finish. Old Schwamb Mill sends frames out that require gilding and other custom finishes.

We piqued Dave’s interest with enough questions that he invited us downstairs to see the big daddy jig – capable of spinning an oval frame with up to three feet of difference between the major and minor axes. Screwed to the template was the largest frame Dave’s ever made – a six foot by four foot oval commissioned by the Harvard Museums. He’d already finished and delivered one; the second was in the final stages of chiseling before final sanding. The size of the walnut frame presented numerous challenges. It had to be built out of eight pieces rather than four, the jig needed additional reinforcing because the template was so big it racked as it swept through a full twelve inch variation in each direction. (The sliding plate offset is one-half the total difference in the axes; a two-foot differential requires the jig be set with a one-foot space in each half-rotation). The mammoth frame is an incredible piece of craftsmanship.

The Old Schwamb Mill builds about thirty custom oval frames a year, a tiny percentage of what they made when the mill employed more than twenty people in the 1870’s. An oval frame online costs about $40; one from Old Schwamb can cost ten times that. But the point of buying an Old Schwamb oval frame is not to just to encase a photo, but to own a piece of handcrafted history.