Need furniture connector advice

[Mark Gibney]

I will be making a desk from 3/4" bamboo plywood that will need furniture connectors to attach the front to the top.

The front is basically a bookshelf, and the top is two sheets of plywood with drawers housed in-between.

The bookcase has two sides, a back, various shelves but no top - the sides and back just butt up against the underside of the plywood top.
What I need to get is a furniture connector to connect the bookcase to the flat of the plywood "subtop" so that I can assemble the desk at the client's home.

I cannot corrupt the surfaces of the bookcase.
So, if I make mortises on the top edge of bookcase sides and back and insert the connector this way I can bolt down through the desk "subtop".

The two legs on the other side of the desk from the bookshelf will be secured by custom metal brackets, T-nuts and bolts. But they don't want a stretcher from these legs to the bookcase.

This was designed by the client and the designer, and they are pretty much decided on this form. They don't understand furniture engineering, and have decided that once the desk is in it's home it won't get any rough treatment and will be fit for purpose.

Any advice on where to look for connectors will be appreciated.

If the above is confusing I'll add a drawing tomorrow.

thanks, Mark

[Bradley Gray]

I've used the sliding connectors made to join bed rails to headboard for on site assembly like this.

[Greg Quenneville]

So the top acts as a torsion box…two sheets with I assume some vertical partitions between the drawers? If so, can you hide the mechanical fastener where it penetrates the lower plywood member? Or does the fastening have to be flush so that a drawer can pass over it?

[Jamie Buxton]

Yes, a drawing would be good. From what I understand, it seems that you could put threaded inserts (I like the brass ones) in the underside of the top, and run connector bolts up from inside the pedestals.

[Mark Gibney]

Here's a couple of Sketchup drawings - hope they help.

Screen Shot 2023-07-09 at 8.22.02 AM.jpg Screen Shot 2023-07-09 at 8.22.47 AM.jpg

As Greg suggests I can remove the desktop and bolt down through the "subtop" of the torsion box into the top bookcase sides and back. The drawer box will be able to slide above any bolt head.
The issue is to find whatever goes into the top of the bookcase that I can thread into.
Bradley I'll have to have a close look at bed rail connectors. Never used them!

[Bradley Gray]

Here's a link
https://woodworker.com/4-bed-rail-fa...su-130-604.asp

[Thomas McCurnin]

Figure 8 table top connectors seem made for this application.

[Mark Gibney]

I can’t use figure 8s or bed rail connectors.
The connection has to be as strong as possible to withstand racking front to back as much as possible.
Also, the bed rail connectors would be at 90* to each other

[Kevin Jenness]

I can’t use figure 8s or bed rail connectors.
The connection has to be as strong as possible to withstand racking front to back as much as possible.
Also, the bed rail connectors would be at 90* to each other

Those bed rail connectors will be more than strong enough. I can't see where they would have to be positioned at 90* to one another unless you put them in the top of the bookcase back, which seems unnecessary.
Assuming the bookcase base is secured to the floor and the other end of the desk is anchored to something, where is the racking stress?

If there is enough room to get a right angle drill or even a ratchet drive in there I would just screw down through the bottom of the drawer case into the bookcase legs and call it good, otherwise I'd use the bed brackets..

Lamello Tenso connectors would work for this, but require an expensive Zeta P2 machine to cut the grooves. Lamello Clamex S connectors can be used with any biscuit joiner but require a 6mm access hole for tightening. Domino connectors need a larger access hole, I believe.

[Jonathan Jung]

Domino 8mm connectors would be ideal for this.

[Greg Quenneville]

You could also try the fasteners used on stair handrails…sort of half lag screw/ half bolt.

The way I would approach this is makea dummy copy of the bookcase sides and back about 1-2” high, drill it for the fasteners, use it as a drilling guide for both bookcase and top. That way you don’t have to worry about doing a precise layout on either piece…and you would have a handy way to ensure the bores are straight.

[Bob Cooper]

Would it be crazy to cut mortises into the bottom of the plywood and tenons at the top of sides, …? Maybe not enough depth?

[Mark Gibney]

Thanks all for the various and thoughtful ideas. I think a bed rail connector on the top of the sides of the "bookcase" and bolt / heavy duty screw down through the "subtop" of the desk into the back of the bookcase will do the trick.
I've advised the client that this is not a typical method of construction, and of it's limitations.
Appreciate all the advice.

[Mike King]

Mod-EEZ RTA connectors would work. https://knappconnectors.com/product/...F-system-sets/

[Mark Gibney]

Mike these are exactly perfect. Thanks.
Ordering them as we speak.