Any woodworkers?

Have you tried to orient the grain differently? I hate it when this happens or it blows out on the end grain. It is an interesting shape. Any hints on what it is for?

 

You could run a dowel from the end piece to support it. Cap it with wood or use different wood. Just throwing ideas

 

Use the plastic frame as backing. Tape the uprights and finalize the bottom straight, then tape the bottom straight and tape the outside of the bottom vertical bars and work the inside of those uprights, then tape the insides of the bottom verticals and work the outside of the verticals. That way there is always some part of the U-shape supported by plastic backing.

AND ...

Try to get the grain going "horizontal to the picture". Note this picture, cutting most of the middle of the plaque out. When I (accidentally) made a test copy out of poplar with grain going horizontal the top arch snapped off. Final product was walnut with grain going vertical (mostly).

And when using the router on the inside and outside of the arch I extended small amounts off a working board and held the rest down to the working board with clamps.

 

Funny ... describing how to use the plastic pattern for the "L" (not sure what exactly it is) tells me that when I make another "center cut out" make a plastic pattern to provide backing support and buy a flush-bit for the router. See ... I learned from a combination of my own mistake and from the "mis-adventures" of others. I be smartly!