What kind of joinery?

[Tom Jones III]

I'm building 3 identical oak chests of drawers simultaneously. I've got all the posts and rails cut for the sides and am now ready to cut the mortises to join the posts and rail. I have been planning to use loose tenons and use a router to cut the mortises. However, the pieces are a little small and I have been considering other options.

The posts are 1.5" x 1.5". The rails are 1.5" deep to match the posts and they are 1.25" tall, 15" long. The side of the chest is 3/4" oak plywood that will be joined with biscuits to the rails and posts.

* First option, one loose tenon 3/4" tall and 1/2" wide, 5/8" deep.
* Second option, two loose tenons side by side, 3/4" tall 1/4" wide, 5/8" deep. The tenons would be 1/4" apart.
* Third option is one or two biscuits. This option would be easiest, and it seems like a lot of the strength of the side is going to be in the plywood. However, I've never done anything like this before so I am a little nervous about it.

Does anyone have experience with option 3? What would you choose in this situation? any other options? I'm leaning towards option 2 at this point but I don't want to waste time and effort if option 3 would be strong enough with the plywood attached.

[Bob Winkler]

IMHO, I might consider Option 4: pocket screws. The plywood panels will provide lots of additional strength. M&T sounds like overkill for this application.

Bob

[Richard Wolf]

With rails that are only 1 1/4 tall you will have a difficult time hiding even FF biscuits. Like Bob said, think pocket screws, if you have never used them you will find they are designed for what you are doing.

Richard

[John Lucas]

I am not sure I follow your details exactly but:biscuits are for alignment and not strength; pocket scrws will be seen; loose tenons...but one per.

[Tim Sproul]

I'd do option 2. But I do have an FMT at my disposal so I'd use traditional m/t rather than a loose tenon.

I disagree with John Lucas regarding the purpose of biscuit joinery. I had thought biscuit joinery was originally developed in Europe as an easy means to joint sheetgood casework parts. Biscuits can provide an extremely strong joint but like any other method, the strength of the joint is determined by how well the joinery is executed. I'm quite certain John is more than capable of executing any joinery method well.

At only 1 1/4 inches, will face frame biscuits fit? I'd be leary of using biscuits any smaller than that.

[Bob Winkler]

The side of the chest is 3/4" oak plywood that will be joined with biscuits to the rails and posts.


The above design decision is what complicates this issue for me. I would definiely want M&T (loose or otherwise) if this were a conventional paneled side. Then the solid wood joinery will be subject to much stress because the panel would "float" within the frame.

But because the oak plywood is biscuited to the frame, I believe that most of the stresses are absorbed by the plywood, and the frame joinery will see little load. The solid wood frame is more like plywood edging than a face frame.

So what I'm trying to explain is that, in my mind, whatever joinery is easiest for you will be plenty strong.:D

Bob
Sorry if I confused things even more....:)

[Tom Jones III]

I'm thinking the same thing as Bob, the plywood is going to take the bulk of the load and the frame is more like really thick edge banding and is there more for looks than anything else.

Richard you are correct, I measured the smallest available biscuits and they are exactly the size of the rails, so the slot would be visible in a few spots.

I had not thought of pocket screws mainly because I don't have a jig and don't feel like taking the time to learn right now.

I think that I will use 2 dowels to join the rails to the posts because of the strength gained from the plywood and I have a bag of dowels on the shelf and I already have a doweling jig. It has been so long since I used dowels that I had completely forgotten about that option until I saw them on the shelf.

Thanks for all the help.