36 - Miter Trimmer, страница 26

36 - Miter Trimmer, страница 26

TECHNIQUE

Strengthening

Miter Joints

A miter joint provides plenty of strength on a small project like a picture frame. But for large wood frames, it's a good idea to reinforce the miter joint Here's how.

Wood Plug

■ One of the simplest ways to reinforce a miter joint is with a wood plug. It produces a strong joint because the face grain of the plug is glued to the face grain of the frame (not end grain to end grain like a typical miter joint).

The wood plug is added to the back of the frame after the miter joint is glued up. Start by drilling a hole that bridges the joint line, see drawing. (I usually drill halfway through the thickness of the frame.)

plugs. Once the holes are drilled, simply cut a plug from the

Open Spline

same material as the frame, see detail. Then glue the plug in place so the grain runs across the joint line, see photo. After the glue dries, it's just a matter of sanding the plug smooth.

■ Another way to strengthen a miter joint is to use an open spline. This is just a thin piece of wood that's glued into a saw kerf in the mitered corner of the frame. What I like about an open spline is you can use different types of wood to create a nice contrast, see photo.

jig. To cut the kerf for the spline, I use a simple jig that straddles the rip fence on the table saw, see drawing. Screwing two supports to the face of the jig at a 45° angle forms a "cradle" that holds the glued-up frame securely in place.

All you need to do to cut the kerf is set the frame in place and make a pass across the saw blade. (I use a rip blade to cut a flat-bottomed kerf.)

assembly. Once the kerf is cut, you can glue in the spline. After gluing and clamping the joint (see detail), remove the excess material with a handsaw and sand the spline flush.

face grain

drill hole halfway

NOTE:

glue plug smooth side down

FIRST: drill

plug to 34 depti

SECOND:

resaw with bandsaw

plug cutter

NOTE: cut plugs

from stock the same \thickness as frame

frame support

fence

26

ShopNotes

No. 36