Chris Schwarz's Blog

Don’t Scorn the Horns on Frame and Panel Assemblies

horn frame and panel assembly

When I build a frame-and-panel assembly such as a door, face frame or back, I almost always add “horns” to the stiles. As a result I almost always get the stink eye from the others in the shop.

What are horns? This is when you make your stiles longer than they need to be, usually 1/2″ to 1″ longer at each end. So when you glue up your frame, the stiles stick up proud of their mating rails. They look like miniature devil horns to my eye. Then you saw and plane the horns flush to the rail as you fit the frame to the carcase.

horns -vintage drawing - frame and panel

If you are a careful woodworker, this might sound like an unnecessary step. But I don’t think so. Early woodworking writers advocated horns as a way to protect the ends of your stiles from self-destructing when you are mortising your stiles by hand. This is a real danger when hand-mortising; without the horns, it’s easy to lever the stile in twain with your mortise chisel.

But I add horns to my stiles even when I use a hollow-chisel mortiser. Here are the reasons why.

– They protect the end of the stiles during assembly. If you have beefy tenons and long rails, it’s easy to bust out the end of your stiles during glue-up. I’ve also watched many people blow out the ends of their stiles when disassembling a dry-fit. They wiggle the rail to remove it, which makes it a lever, which makes bad things happen.

– Horns allow extra purchase for your clamps. If you build traditional doors with through-tenons, you limit the area where you can clamp the joint during assembly. You have to clamp to the side of the tenon. If you have horns, you can get two clamps on the joint if need be.

– Horns play nice with plow planes. Perhaps I’m ham-handed with a plow plane, but whenever I plow a stile or rail, the far end of the groove (where the cut begins) is always a little more raggy than the rest of the groove. My guess is that because this area sees the most action, it gets a little more wallered out. If I have horns on my stiles, that ragged area gets trimmed away (also, it gets trimmed away on the rails when I cut the tenons).

– My stiles are never too short. I always make my mortises a little longer than they need to be so I can knock the rail exactly where I want it during glue-up to get a tight seam at the shoulder of the tenon. If I have a horn on my stile, I’ll never end up making my stile too short. It will always need to be trimmed to fit. Side note: I also make my rails a little wider (about 1/16″) than necessary to ensure my finished assembly will never be too small for its opening.

– Horns protect the stile during wedging. Traditional workshop practice is to wedge the through-tenon from the outside during glue-up. If you have a horn, you are much less likely to split the stile during wedging.

– Christopher Schwarz

frame and panel trim horns backsaw

5 thoughts on “Don’t Scorn the Horns on Frame and Panel Assemblies

  1. Don Williams

    I frequently add an inch or so to the stiles when making custom doors in our shop. The extra length helps protect the bottom edge of the door during transportation. Then the at the jobsite, after measuring and ckecking the jamb for square, I trim the bottom to match the height of the threshold.

    Thanks, Don

  2. Murray

    In the cabinet shops I’ve worked in, the rails were 1/16 – 1/8" wider, and the stiles always had horns so you could always trim a door down to fix a slightly out of square assembly, which never happens to any of us.

  3. jacob

    Plus it helps with dry runs – you can pull the thing apart by hammering the horns.
    It’s standard traditional practice but you wouldn’t know by merely looking at old joinery, as they have been removed!
    Makes you wonder what other evidence is gone e.g. I always make through tenon ends about 1/2" over length, for similar reasons.

  4. MikeH

    Thanks for a great idea which I myself would never have thought of in a million years.

    As far as the stink eyes are concerned? Shame I say. They’re just jealous that you thought of it first.

    Non carborundum illegitimi!

Comments are closed.