Miter Joints and ways to make them stronger.

miter joint

Miter joints, like butt joints, need to be reinforced to be useful. If you can think of a way to beef up a miter it's probably already been done.

Very seldom will you find a joint that hasn't been beefed up somehow. Besides just glue I've seen miters that have been half-lapped, biscuited, had butterfly inserts, splined, doweled and the list goes on.

Woodworkers go to the effort of using beefed up miters because these joints look best in certain applications.

Decorative picture frames would be very hard to make using any other joint. Cabinets use doors with mitered frames for looks and production efficiency. Decorative trim in houses are installed with miters  strictly for looks. The same goes for furniture.



Here's a few of the common ways to make a miter joint stronger.


Miter joint reinforced with nails, screws or dowels

Nails,  Screws or Dowels - Driving some type of mechanical fastener through the outer edges is ok to do if you can cover it up with filler and finish.





Miter joint with dowel inserts

 Dowels - Spanning the joint thru the middle is quite common if you can drill the dowel holes accurately.  Using a positioning jig to drill the holes is a must for a straight joint.





miter joint reinforced with loose spline

Loose Splines -  These are more forgiving than dowels but you still have to have a good way to cut the grooves for the spline accurately.  Although you can use a table saw I prefer to use a router and table for more accurate grooves.




Miter joint with pocket hole screws

Pocket Hole  Screws -  The great thing about pocket hole joints is the fact that you can keep working without having to stop and let glue dry.  It's also a very tight and strong joint.  






miter joint reinforced with biscuit insert

Biscuits -  Biscuits are a good solution for alignment and strength.  The down side would be the time it takes for glue to dry.






miter joint reinforced with corrugated fasteners

Corrugated Fasteners -  Are used to hold joints together while the glue dries and is also used to repair broken joints.  These fasteners are seldom used anymore as there are several ways to beef up a joint that's definitely a better choice.




Half lap miter joint

Half Lap -  A variation of the standard miter joint.  The miter is only cut half way through each piece and the other half of the thickness becomes the glued up area that holds the joint together.  





Miter with a butterfly insert

Butterfly Inserts -  A key or insert that looks like the wings of a butterfly.  This insert is embedded across the joint to strengthen and hold it in position.





Miter with bonding plated

Plated Miter - One or more plates screwed to the back side of the miter is another option to beef up the joint.






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