I you have a table saw you can make a jig that will cut a pice of thin hardwood at any angle. Mount it to larger piece with adhesive like rubber cement and saw proper angle, sand and you have it. Some pieces can even be sawn with miter gauge that table saws have. I have done this for profile and conventional mounts. I wanted to use some kind of plastic but knew it would have to withstand intense vibration and some heat. Some company (J-tec, I think) makes a mounting plate assortment out of plastic but it won't hold up that well because the vibrations cause it to crack. A belt sander with a miter gauge will work also but I don't have one.