Mitered newel post

[TIDE500]

What is the best method to attach the four sides of a mitered newel post together?

 

[red]

I've used biscuits in the past.

Red

 

[Charles Lent]

Lock Miter joint, or biscuits, or cross grain splines. Each will prevent the mitered joint from slipping during glue-up and will also add considerable strength to the mitered corners that would otherwise be a poor joint for strength. For the biscuits or cross grained splines, a slot cut of the needed thickness at 90 degrees to the 45 mitered joint surface can be used. I usually place this cut close to the inside of the corner in order to keep it from weakening the outside surfaces.

For cross grained splines, I make them with my tenon jig and Unisaw. Getting the jig so that what is normally the waste (outside surface) when cutting the tenon becomes the perfect cross grained spline. Once the thickness of the spline is set to match the width of the spline saw cuts in the project, you can make one spline from each donor board surface and then flip the board end for end and make two more. I then use my chop saw with a stop to cut the cross grained splines (and the tenon) off of both ends of the board, getting 4 cross grained splines. You can make many of these splines by repeating the process and then use them end to end in your project, or use them like biscuits, placing them with spaces between them in the miter slots. The cross graining is necessary for strength. Using them across the mitered joint in your corner post assembly will also prevent the joint from slipping during glue-up, as does the biscuits or the lock miter joint.

Charley

 

[Jeff]

I don't know if there's a "best way".

Countersunk 6D finishing nails (2" long) work fine for 4 sided posts.