I am building 5 individual bookcases(total of 15 feet) that will be built-in. When I build free standing bookcases I use a sliding dovetail for the bottom shelf. For this project, with each unit attached to each other and to the wall, do you think using a dado for the bottom shelf is ok. It will be faster for me to get the project done, but I will do a dovetail if that seems better. Appreciate your comments.
Fine Woodworking Recommended Products
Wen 6321 Belt Sander
Weight: 6.2 lb. Amps: 7 Variable speed: No Belt alignment: Good Material removal rate: Poor Sanding flatness: Very good Shaping/scribing: Fair Handling on side: Very good Dust collection with hose: N/A
Whiteside RU5150 1/2-in. Up-Cut Spiral Bit
1/2-Inch Cutting Diameter
1-1/2-Inch Cutting Length
1-1/2-Inch Cutting Length
Osmo Polyx-Oil
"If I had to choose one of these hard-wax oils to keep on hand, it would be Osmo Polyx-Oil. It’s relatively affordable and very easy to apply." -Adam Godet
Glue Bottle
My favorite glue bottle is a ketchup dispenser. Inexpensive and you can cut the tip to customize glue distribution. If you always put the cap back on, it never clogs.
Ridgid R4222 Miter Saw
Especially considering the price, among the lowest of the bunch, the Ridgid R4222 has impressive adjustability. It has the largest crosscut capacity of all the saws. And the miter and bevel settings have the largest range of travel, and a bevy of detents. However, the power switch is clumsy, a bad design especially for lefties. The adjusters are either hard to use or hard to reach. Plus, its slider needs the most room out of any of the saws.
Replies
A sliding dovetail is stronger but that would be relative here. I have been working on making tight straight sliding dovetails, not the tapered variety. Interested in other opinions.
Use the dovetails on the outside units where a smack from a vac could open it up. The inside ones aren't going anywhere. If you are worried about them add a coupla screws where they'll never be seen.
The overall structure should be very rigid once the units are joined to each other and attached to the wall. Therefore, I think a regular dado on the bottom shelf would suffice. If you like, add some hidden screws for extra insurance.
I'm just went through this exact situation a couple of months ago. I am making Becksvoort's 15 drawer shaker chest. Becksvoort used sliding dovetails on his. It's beyond my hand tool skill at this point (though I will do them on a future project) and I don't own a machine router. I wanted more than just a dado to secure the horizontal pieces. What I did was on the bottom and middle of this piece was to also include a through tenon. On the outside of this tenon, I made it a total of 1/8" wider than the inside. When I glue it up soon, I will use wedges on the through tenon so there is more than just glue holding the sides together. Is it necessary? Probably not but I will feel much better about it.
I have been working on making sliding, not tapered, dovetails, I am using a collar and two routers to form the base and a router table with the dovetail bit to form the insert. I have been getting good results.
The dado will be more than adequate with modern adhesives. Anything that will break that will also break a sliding dovetail.
Even Ikea stuff made of really crap panels and a couple of screws will last 10-15 years - a lifetime if it is not moved.
In the end, even if a sliding dovetail is three times as strong as a dado joint, the dado is still five times stronger than it needs to be.
+1 on what the last poster said. If you’re a Cosman neophyte he believes dadoes are enough. If it’s good enough for him it’s good enough for me.