You must remember that the wedges must go perpendicular to the grain of the piece that has the mortise or there is a risk of splitting the piece when you drive those wedges into the tenon.

This wedged tenon is usually called tusk tenon, where a wedge shaped key crosses the through tenon to lock things in place, making the joint sturdy and allowing the piece to be disassembled.

Also, the image above is much more clear then yesterday’s which was just a close-up of the joinery detail with the x-ray feature in SketchUp turned on.

When making this type of joint there are a few points to consider:

• The angle on the wedge should be between 3º and 5º
• The mortise for the wedge is located slightly inside the post
• The wedge should be made from a wood that is as hard or harder than the stock they wedge
• Single loose wedges are usually oriented vertically and double loose wedges are usually oriented horizontally

Attached files:

• Wedged tenon

In the last few days I’ve been busy designing a traditional crib for my baby daughter and thought it would be a nice feature project for the blog. You can download the 3D SketchUp model for free and check all the measurements and joinery details for yourself.

This project will be my first furniture piece and I feel nervous just to think about it. For one I have never build anything of this size and I want to try a few new things both in terms of construction and finishing.

The frame will have to be a knockdown design so it will be easy to get it out of the shop and into the bedroom. Instead of using standard hardware for this purpose I decided to join the side rails to the posts with a wedged mortise and tenon with a loose wedge made of ebony. This will be one of the design features of the piece influenced by the arts and crafts style.

Another design feature will be a drop side rail for which there are no details in the drawing yet. I have a few ideas in my head at the moment and will post an update in the future.

The crib will be built with solid cherry and will have a shellac and wax finish which are both non-toxic finishes, something to pay attention when making furniture for babies. Both shellac and beeswax are approved by the FDA and are widely used in the food and drug industry.

I also tried to follow all the guidelines regarding crib design. The distance between the slats in the rails is 60mm, the rails are approximately 600mm high and the posts don’t protrude above the top headboard.

The images on the left show some of the joinery details.

The first image is a simple mortise and tenon used to attach the top headboard to the posts, nothing fancy here.

The second image shows something I’ll be very proud of if it works out well.

The bottom footboard will attach to the post with a mortise and tenon which will have to make enough room for the through tenon in the side rail which in turn will be wedged to lock thinks in place.

I guess that if this isn’t sturdy enough I’ll add some screws to the joint and cover these with some ebony pegs. What do you think?

Attached files

• Traditional crib