MDF vs Plywood

[JDCrae]

Slight correction on my post.

The joint I was referring to, is currently called a lock miter joint. See here: http://www.rockler.com/rockler-45-deg-l ... 2-in-shank

I had seen a table saw blade that was invented to do the same thing, which is pretty awesome, but I do not believe it has been produced commercially. You can see that here. https://www.youtube.com/watch?v=S074ke-EJ6U

For plywood boxes, I think this is a fantastic joint method. It truly locks it in place, locates the seam perfectly and great surface area for glue up.

Tom's suggestion of biscuits is certainly a good way to go. Many a cabinet has been constructed with biscuits and are still standing, and straight today.

[tomp]

That is a very clever way to make a strong joint. It appears from the video that you must have a router table to control the cuts with this bit. I only have a hand held router. Looks like I might have to get a table for it

Tom

[brombo]

If you make a router table I suggest using two sheets of 3/4 inch baltic birch plywood glued together with opposite wood curvature facing one another (so the two glued together are flat). You may want to check out the Woodworkers Club in Rockville -

http://woodworkersclub.com/

[m1garandusa]

What worries me the most about this project, more than the material choice, is the severe angles that need to be mitred on a few of the pieces where they join other pieces. The stuff between 90 and 45 degrees is easy, but the ones that require mitres only 17 degree from parallel with the plane formed by the raw lumber, for example, will require me to hold the wood perpendicular to the saw table. I see that requiring a jig of some sort. That actually makes me think of another question: which is the better material for making extremely high angle mitre cuts? MDF has a uniform consistency, but how does plywood behave while trying to cut extreme angles? Do the laminates misbehave when you are makeing a bevel so shallow that the sawblade is only 17 degrees from being parallel to the laminates? Does the piece tear/rip or delaminate?

[tomp]

I actually had to make some cuts with those types of angles and yes I had to hold the wood vertically. I did make a jig but more important is a zero clearance saw insert where you put the blank insert in the table and then raise the blade while the saw is running. That cuts the insert to exactly fit the blade leaving no space for the work to bind between the blade and insert. That will probably be a two person job with larger pieces of wood. The good thing about the plate joiner is that it is adjustable for any angle. If you wind up with a thin section you can also use the face frame blade and matching biscuits.

Tom

[brombo]

Another good source for router hardware is -

http://www.mlcswoodworking.com/shopsite ... tre_anchor

Video for ripping acute edges -

https://www.youtube.com/watch?v=m2gl9OEW8tg

An alternative would be to make some molding out of solid wood with the acute edge cute into in (you could use a router or table saw to make the molding) and glue it to the plywood with the usual 90 degree edge.

[m1garandusa]

That YouTUBE video was fantastic. I think even I could do that.
V/R
James

[brombo]

If anyone wished to borrow a router, router table, and bits I could supply them.

[tomp]

The combo of those two pieces of wood is a great idea. Thanks.

[brombo]

Actually you could make a single piece of molding out of solid wood to join two pieces of plywood each with a normal 90 degree edge. I would recommend Titebond III glue for bonding. Biscuits could also be used to attach the molding to the plywood. Solid wood molding would also cover the edges of the plywood making finishing simpler.