# 3/4 " Plywood Box Joints



## Perk318 (Mar 2, 2012)

I want to make a simple box (finger) joint in 3/4" plywood, using a 3/8" straight bit. When I tested my cut on a scrap piece all I got was a lot of tear out. Is there any type of bit to use on plywood that would prevent this tear out or do I need to consider another type of joint. I am trying to make drawers for my new assembly table. I have not tried A rabbit bit yet, but that is my next choice if I can not get finger joints to work. If I can not get it to work on the router, I can always use the table saw to make the rabbit. Any suggestions from the community??


----------



## cagenuts (May 8, 2010)

Did you use a backer board perhaps? This would help prevent the tear-out.


----------



## Mike (Nov 22, 2004)

Jerry, plywood does not work well with box joints because of the layered construction. I would use a different joint.


----------



## Perk318 (Mar 2, 2012)

I came to the same conclusion. I tested a rabbit joint and it works just fine. Thanks for your input


----------



## JOAT (Apr 9, 2010)

3/4" plywood? Sounds like serious overkill to me, unless you're planning on putting anvils or something in them. :haha:
Years ago I made a toy box, around 12 years ago in fact. I used 1/2" plywood for the ends, and 1/4" plywood for the sides, if I recall right, could be 1/2" for the sides too, but don't think so. Anyway, just butted the sides to the ends, then used a glue block 1/2"X1/2" inside the joint. Same on the bottom seams. That toy box is still in use today, and except for the fact that someone (Oh Lord, I hope it wasn't me) painted both sides with some really horrible purplish color, it is as good as when it was made. So if you want a really simple joint, that's the way to make them - but remember, for something that size I consider the glue blocks vital for strength. For a drawer, I personally would just glue it all together, and probably leave out the glue blocks, depending on how I felt about it at the time.


----------



## thammons (Mar 26, 2012)

Would 1/2 inch baltic birch type plywood take a cleaner box cut? also, I just bought a two-blade box cutter for my table saw (haven't used it yet) that cuts 1/2 inch box/fingers combined one way (back to back, in a sense) and 3/8 inch combined the other way (front to front); I hope that makes clean cuts in 1/2 inch plywood for drawer joints
th


----------



## DaninVan (Jan 1, 2012)

*Router joint*

Yeh, that was my reaction to the 3/4" plywood sides. That's pretty heavy construction for a drawer?! 
http://www.whitesiderouterbits.com/catimages07/lockingdrawergluejoints.gif

Something along that line would be more than satisfactory. By the time you glue (and finish nail it) you'll need a hammer to break it apart. In thirty plus years I've never had a drawer come apart (that _I_ built. 1/2" plywood and 1/4" for the bottom, unless you _really_ want to load the drawer, than 3/8".


----------



## bobj3 (Jan 17, 2006)

Router Forums - View Single Post - Why aren’t my dovetails cutting?

==


----------



## Perk318 (Mar 2, 2012)

The 3/4" plywood was FREE, I was given (5) full sheets. You better believe that I am going to use for this project. It is B/C grade, but will do just fine for drawer interiors. The outside face plate and front ends will be a better quality wood. I just finished all of the rabbits for (8) drawers. All that is left is the gluing and some nails from the air gun.


----------



## JOAT (Apr 9, 2010)

Perk318 said:


> The 3/4" plywood was FREE, I was given (5) full sheets. You better believe that I am going to use for this project.


Definitely the right attitude, Never, Ever, pass up free wood.


----------



## Neil Tsubota (Mar 20, 2010)

Correct me if I am wrong. 

A "ruler joint" is known as a "drop leaf table" joint. But the bit in this picture is correctly labeled as an interlocking joint. Typically, used between drawer fronts and 1/2" or 1/4" sides, and back.


----------



## cagenuts (May 8, 2010)

neiltsubota said:


> Correct me if I am wrong.
> 
> A "ruler joint" is known as a "drop leaf table" joint. But the bit in this picture is correctly labeled as an interlocking joint.


I think it's called a '*rule*' joint and I don't see any picture.


----------



## LexB (Apr 12, 2010)

I used a 1/4-inch spiral bit for making box joints in 3/4-inch plywood. I did get tear-out, but because this was a paint-grade project, I just puttied over the joints and sanded flush. Now I have a lock-miter bit and plan on using that on my next 3/4-inch ply project.


----------

