Looking for advice: Dado or Sliding Dovetails?

ryansm7 · Post by **ryansm7** » Thu Feb 17, 2011 9:51 pm

I'm making a chest of drawers and looking for some advice on the carcus joinery (side to runner): Dado or Sliding Dovetails?

I'd like to have it as sturdy as possible, but don't understand the variables.

I understand that a dado would be a typical method to allow for humidity changes and expansion.

Would a sliding dovetail allow for expansion just as well?

I'm using hard maple for all materials.

[ATTACH]11947[/ATTACH]

JPG · Post by **JPG** » Thu Feb 17, 2011 11:42 pm

ryansm7 wrote:I'm making a chest of drawers and looking for some advice on the carcus joinery (side to runner): Dado or Sliding Dovetails?

I'd like to have it as sturdy as possible, but don't understand the variables.

I understand that a dado would be a typical method to allow for humidity changes and expansion.

Would a sliding dovetail allow for expansion just as well?

I'm using hard maple for all materials.

[ATTACH]11947[/ATTACH]

With center drawer guides, I would think dado slides would be adequate(and less prone to sticking).

ryansm7 · Post by **ryansm7** » Fri Feb 18, 2011 2:14 am

JPG40504 wrote:With center drawer guides, I would think dado slides would be adequate(and less prone to sticking).

Also, I'm not sure about terminlolgy]11948[/ATTACH]

I've read that only the first three inches (toward the front) of the runner should be glued and screwed to the side of the carcus. Since the runner is in the Dado/Dovetail it allows for expansion from front toward the back direction; since the back is free to move.

The strenght I'm looking for is holding the carcus "side to side" firm, but again I'm not sure about the side to side expansion versus front to back expansion.

It seems that a dado would allow the "web frame?" to move in all directions;
whereas a dovetail would only allow movement from front-back.

dasgud · Post by **dasgud** » Fri Feb 18, 2011 9:13 am

Whenever I've built cabinetry that required joinery and no fasteners I've only used dados. As far as I know, none have failed either. I want to make sliding dovetails some day, but more for adding detail rather than strength.
If I understand your comparison correctly, you're asking if sliding dovetails will be stronger against the sides pulling away from the framework. I'm not an expert, but it seems to me that if you don't glue the whole joint, then the dovetail will be more effective over time. Since you're using frame work for the drawer dividers, the grain patterns will run differently so the expansion of the cabinet sides will be greater than the divider frames. In that instance I think that your gluing strategy (glue the first 3" or so and leave the middle unglued) is proper and the dovetails might be the best choice.
Another option you may consider is to use glue blocks under the framework. Then you can spot glue and use screws. That would be the 3rd best choice though, and far below the 2nd best, which would be dados.
I hope you take pics of this project through the process

. I'd like to watch.

JPG · Post by **JPG** » Fri Feb 18, 2011 12:49 pm

ryansm7 wrote:Also, I'm not sure about terminlolgy]11948[/ATTACH]

I've read that only the first three inches (toward the front) of the runner should be glued and screwed to the side of the carcus. Since the runner is in the Dado/Dovetail it allows for expansion from front toward the back direction; since the back is free to move.

The strenght I'm looking for is holding the carcus "side to side" firm, but again I'm not sure about the side to side expansion versus front to back expansion.

It seems that a dado would allow the "web frame?" to move in all directions;
whereas a dovetail would only allow movement from front-back.

I answered the wrong 'question'. I would dovetail per your need for side to side support as you described above.

charlese · Post by **charlese** » Fri Feb 18, 2011 3:42 pm

ryansm7 wrote:I'm making a chest of drawers and looking for some advice on the carcase joinery (side to runner): Dado or Sliding Dovetails?

I'd like to have it as sturdy as possible, but don't understand the variables.

I understand that a dado would be a typical method to allow for humidity changes and expansion.

Would a sliding dovetail allow for expansion just as well?

I'm using hard maple for all materials.

[ATTACH]11947[/ATTACH]

Hi Ryan!

Since you are using solid maple boards for the sides rather than plywood - the wood movement to be concerned about is the front to back movement of the two sides. The deeper the chest (wider the sides) will give more movement.

The runners do not present a movement concern, as their long grain will run from front to back and movement is negligible along long grain.

Seems to me you definitely have two options here:
1) If you have no problem making sliding dados this would be the preferred way to go for longevity. As you have indicated glue on the front few inches would be plenty to hold the runner in place. The dovetails will also add side rigidity to the chest.

2) The second choice is to make dados. these would work well if you make three glue blocks to place under each runner. These blocks would be glued and screwed to the sides. --two screws each toward the front and back of the blocks to allow room for a slot. The slots will allow a screw to pass through the block and into the runner. These slots would be about 1/2" or 3/4" long and would allow the vertical screws (the screws driven into the runners) to slide forward and backward. This second choice would hold the carcase and the runners quite firmly also. The only problem in using blocks is - Would they impede movement of the drawers. If you have some side room for the blocks this is an easy way to go.

Concerning chest stability - the back that will be fit into the rabbets shown in your pictures will add tremendous resistance to racking of the chest.

P.S. I see in your pictures, you will have center drawer guides. Will you also have side guides or will the drawers ride agains the carcase sides?

ryansm7 · Post by **ryansm7** » Fri Feb 18, 2011 10:43 pm

Thanks for the advice. I am in the planning stage right now and will keep a record of the project.

I've always liked the dovetail joinery. Probably since watching my dad's endless repairing of box joint dresser drawer.
They never seemed to stay together.

The chest will actually be used for storing tools in the shop. I'm hoping to make several variations. Peg board never quite worked for me - kinda like looking in the pantry for a can of tomato soup; I can't find it but I know it right in front of me.

As for the drawer guides; I'd really like to do parallel sliding dovetails.

[ATTACH]11962[/ATTACH]

Check out this article in Fine Woodworking from March/April 1996

"All-Wood Extension Drawer Slides - Telescoping dovetails support a fully opened drawer with style by Karen Robertson"

[ATTACH]11964[/ATTACH]

If I get greedy

mgdesigns · Post by **mgdesigns** » Sat Feb 19, 2011 10:22 pm

I know from the sounds of your request, you wish to make a durable well-crafted wood joinery exercise. But, considering you plan to store tools in it - perhaps full extension high capacity metal drawer glides would be a wiser choice?

charlese · Post by **charlese** » Sun Feb 20, 2011 1:45 pm

mgdesigns wrote:I know from the sounds of your request, you wish to make a durable well-crafted wood joinery exercise. But, considering you plan to store tools in it - perhaps full extension high capacity metal drawer glides would be a wiser choice?

Ryan - gotta admit my lower jaw dropped a bit when reading you wanted a shop chest. I believe mgdesigns recommendations to be very well put!

In fact, to pay for a good portion of the price of metal drawer slides, you could replace the hard maple with Plywood. If concerned over appearance, you can paint.

Metal drawer slides will also allow room be twee the sides of the carcase and the drawers - therefore you could use dados and support blocks. You could even glue the entire dado.

ryansm7 · Post by **ryansm7** » Sun Feb 20, 2011 4:52 pm

@ mgdesigns

I really did not think that metal drawer glides would be necessary given the drawer sizes and potential capacity.

The design I'm using is from the 1998 Sept/Oct issue of Fine Woodworking:

[INDENT][INDENT]"An Inspired Tool Chest"
Duncan Phyfe''s personal tool chest begets a handsome adaptation...

by Bill Crozier[/INDENT][/INDENT]

http://www.finewoodworking.com/FWNPDF/011132054.pdf

[ATTACH]11990[/ATTACH]

The smallest drawer opening is 7-1⁄2 in. x 1-3⁄8 in (six of them across the top).
and the largest drawer is 23 in. x 2- 1⁄2 in. (two on the bottom)

The strength consideration is based on the 1/2 in web-frames across the horizontal.

I am fairly confident of the "vertical drawer dividers" ability support the rows of drawers.

.