Lock Rabbet joint

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Bas

Recovering tool addict
Bas
Corporate Member
I'm making a drawer, out of 3/4" plywood. As part of my continued education, I want to use a lock rabbet joint, since I've never done that one before. I want to use the table saw, since my my box joint blade does both 1/4" and 3/8" cuts.

I found a great video on the Wood Magazine web site, but the example is done using 1/2" stock for the sides. I'm trying to figure out how to best adapt this for 3/4" stock.

Thought #1 is to keep the dado at 1/4" deep, then just cut away more on the mating piece to create the 1/4" rabbet. The video shows how you can use a 1/4" shim to avoid having to reset the fence, I don't think I need a shim with 3/4" stock.

Thought #2 is to make the dado 3/8" deep, and the rabbet 3/8" wide to match, half the width of the stock. The shim would have to be 3/8" to match.

It would seem the 3/8" dado/ rabbet would be stronger, and setup more intuitive. Anything I'm missing here? I don't have any spare stock :)
 

Jim Murphy

New User
Fern HollowMan
I don't make mine using the technique shown in the video, but here's what DIY says to do.

http://www.diynetwork.com/diy/hi_tools/article/0,,DIY_13936_4219278,00.html

Use a 1/4" dado stack for this project. Set the blade 1/4" above the table.

Set the fence 1/4" from the blade edge.

Place a board flat against the table top and tight against the fence.

Make a cut on all the way across the board. This board will be the drawer side (figure A).

For the drawer front, cut a 1/4" x 1/4" rabbet. So that you don’t have to change the blade setup, Use a 1/4" spacer board between the fence and the board. Use your miter gauge to hold the board and maintain the spacing as you push through the cut (figure B).

Change the blade height to 1/2".

Stand the drawer front vertically for the next cut.

Make the cut through the end of the board, holding the board tight against the fence (figure C). Make sure your fingers are holding the board above the cut area and out of harm’s way.

Put the two boards together and you’ve got a lock joint. Remember to use glue to bond the joint (figure D).

To make a lock joint on a table saw using 3/4" material, follow the first few steps until you get to step 5, cutting the rabbet. For 3/4" material, you will need a 1/2" x 1/4" rabbet, so don’t use the spacer to make that cut. Then, raise the blade to 3/4" to make the vertical cut.
 

Rob

New User
Rob
Thanks for this thread Bas, I'm getting ready to build some drawers and was going to use regular dado's. I like this idea much better.
 

Bas

Recovering tool addict
Bas
Corporate Member
Thanks Jim, I saw David Thiel's method but the joint appears to be somewhat different than the one from Wood Magazine. If you look at the last picture, it's more two dado's interlocked than a dado/ rabbet joint.

I think I just need to go to the table saw and try this out with some scrap pieces. I'm having a tough time wrapping my head around this one.
 

woodrat

New User
Archie
Bas,

Thanks for the link. I, too, am getting ready to make some
drawers and find that video very helpful.

I was thinking about finger joints(box joints, no pun intended)
but after seeing that video I'll be using the lock joint. :icon_thum

Woodrat
 

Bas

Recovering tool addict
Bas
Corporate Member
I made some drawers using box (finger) joints not too long ago, and when using solid wood, it's a great option. I made a super simple jig that produces very pretty results, and there is so much glue surface that thing is never coming apart. For plywood, box joints aren't so great, unless you have some really high quality Baltic Birch. Even then, you have to watch out for small layers chipping off. DAMHIKT.

(I had planned to use solid wood for the drawers, but I screwed up the stock layout and ended up being short on material.....just making a virtue out of necessity)
 

Joe Scharle

New User
Joe
The whole crowd seems to be making drawers! I'm building my first ever "ALL KREG" cabinet, including the slide installation tool. BTW, I much prefer to use a 3/8 spiral bit on the RT for that joint.
Joe
 

Bigdog72

New User
Geoff
I'm making a new drawer for my saw blade storage cabinet. The one I am replacing lays in ruin after I shimmed it too tight and then jammed it home. Took awhile to beat that sucker out of there. Anyway I like half blind dovetails (machine made) in plywood but I do use the lock joint in real wood.
 

Bas

Recovering tool addict
Bas
Corporate Member
Turns out to be a lot simpler than I thought with 3/4" stock. I used a 3/8" dado blade (well, box joint blade), a 3/8" shim, and followed the original recipe. The trick is to cut lots of test pieces, and get progressively to the point where it's the exact right dimensions. That means the side is flush with the front (1/128" proud is ideal) and everything fits snugly. I cut mine a little too loose I think, but the glue made the wood swell a little and it went together great. A little fiddling with the clamps and it was square.

Best of all, I get to do it all over again tomorrow, since I forgot to glue in the bottom :eusa_doh:

Sometimes I really hate this hobby.
 

Rob

New User
Rob
Bas, are you actually going to glue in your bottom? I was just going to use 1/4" plywood, and slide it in a dado cut at the bottom and leave it loose, like a panel.
 

ScottM

Scott
Staff member
Corporate Member
Rob I recently made 5 lock rabbet draws using 1/4" plywood for the bottom. I glued mine in just for a little added strength. I only used a couple dabs on each side and did not run a bead all the way around.

Just make sure your draws are real square when you glue up or they won't install correctly. DAMHIK
 

Alan in Little Washington

Alan Schaffter
Corporate Member
I'm a little late to this thread, but technically speaking the joint commonly referred to as a drawer lock joint

(It is not a lock miter, that usually takes a special router bit to make)
cmt-lm3.jpg


is not a true "lock joint" (neither is the lock miter joint) because you can pull them apart in one direction.

It is possible, using an 1/8" saw blade or a 1/4" dado blade to make a true locking drawer joint that, without any glue or mechanical fasteners, won't pull apart in either direction (front or side). You must slide the parts together vertically.

This joint requires a minimum of two cuts on each board at each corner and I think works best with 1/2" thick drawer sides and 3/4" (or thicker) drawer fronts. You don't cut a rabbet on the ends of the drawer front, but the process of making the cuts creates one- one that is actually needed. The depth of the rabbet depends on the strength of the wood your are using.

You need to be careful and keep track of the cutting sequence. But with only a few fence/table spacers, you can make this joint on the table saw without any jigs, using only a single blade height and fence setting.
 

Bas

Recovering tool addict
Bas
Corporate Member
Bas, are you actually going to glue in your bottom? I was just going to use 1/4" plywood, and slide it in a dado cut at the bottom and leave it loose, like a panel.
Yes, I plan to glue it in. Not so much for strength, just to makes sure it doesn't rattle. I suppose you could leave it loose. The dado and stuff in the drawer will keep things in place. But I like the additional bond from the glue. Since it's all plywood, there are no concerns about wood movement, like you would have with a solid panel.
 
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