I'm not sure how 18th-century planemakers attached horns to planes, but I decided on a sliding dovetail for strength.Thinking it would protect the fragile corners of the dovetail, I added shoulders so that it would sit back from the front of the plane by way of a shallow recess.
The dovetail is hidden because the horn covers the joinery. I have no idea if this matches the method used 300 years ago, but it worked really well.

Even though there is a cross-grain situation with the horn and plane body, I glued it in place. We'll see what happens over time.
I had thought to circumvent any cross-grain issues by burying the bottom of the horn in the body and cutting a deeper mortise than necessary to allow for movement. Changed my mind for whatever reason, but I do think that's a viable option.
The last two photos show the horn with oil applied. It also shows the decorative border I carved along the lower portion of the plane and the final shape of the plane's body.I should have glamour shots of Sven ready on Thursday. The oil is drying, then I'll apply some wax to the outside surfaces.
