has anyone ever seen metal splines used to join casing miters? not the ones pounded in on the back side of the trim. the ones i'm looking for are pounded in from the outside corner of the miter. first the two pieces are slotted with a router bit on the miter edge. then they are put together with glue in a corner vise. the metal spline is then pounded in from the outside corner of the mitered pieces. the splines look like an arrow from the top and an H from the end. i've used these before but can't find anyone who sells them. i'm thankful for anyone's help in this matter

paul