On this frame, where the beads are incised, fluting with the grain. Most of the fluting I've seen on antique frames has appeared hand carved, though it would not surprise me if there were some fluting engines available in the 19th. century. If they could come up with the Stanley 55, a fluting engine shouldn't have been too difficult.
I'll leave the 55 for another post, and concentrate on how I mark out and carve fluting.
These are some of my marking "gauges" for drawing the lines for the fluting.
And, here we see one of the gauges in action. The blue tape has been applied as a handle, to facilitate moving the gauge. I start with flat sheet metal; in the example above, that's from an old aluminium license plate. Being careful to keep the bend at a right angle to the edge, I clamp the metal in a metal working vise, and bend and hammer the "fence" of the gauge in. The shape is done by clamping different sizes of pipe in the vise and bending the metal over the pipe. A certain amount of hand fitting is required. The holes in the gauge can be used as a measure for the next line, or as I have done above, measure can be marked off of a ruler.
The horizontal line is the starting point for carving the flutes. Above, the inner part of the cove will be overlaid with an inner frame, so there is no end point.
Carving, now there's the rub. Depending on the size of the flutes, the size of the molding being fluted, I may be able to use a straight gouge, or it may require a bent gouge. Bent gouges come in a variety of shapes, some having a tight bend, near the edge, and some with a long, sweeping bend. I practice on scrap pieces of the molding, to work out size, and which tool I will use. If I need to lever the gouge against the frame, I will add a very thin piece of wood with double sided tape, to prevent marring the molding. Depending on the wood itself, I can often carve a flute in a single pass, or it may take little bites to complete one flute. Usually, a few passes are needed; the initial one and then several clean up passes. I do minimal sanding and filing, preferring to get a few coats of gesso on, and then do the sanding and filing. I use a variety of files, rifflers, and little sanding blocks that I custom make. Seldom can I use one method for an entire frame, as there will be hard areas, soft, grainy and not, needing different tools to accomplish the same end.
Studying antique frames closely, reveals the "hand", some waver, wiggle and tilt, but from a proper viewing distance, all is well, the little irregularities disappearing. Besides they indicate "hand" and character. I'll save my thoughts on "hand" and it's place in ones own time and culture, for another post.