joining bookmatched slabs

[William Hamilton]

I've begun the process of making my live edge, bookmatched walnut trestle table. The finished top will be 80" x 48" x 1.75".
At what stage of the game do I actually join the two slabs together? I'm going to leave a small gap between the slabs (between 1/8" -1/4"). I'll be using 5 rosewood butterfly keys between the two slabs. Will I be able to move those joined slabs around to work on them if they are just joined by butterfly keys? The keys will be about .75" to 1" deep. I don't want a horrible accident where they pull apart or anything if I'm flipping the slabs over. I'm not worried about weight since I'm a big guy and have help.
The slabs will actually sit on the base via dowels. I'll also be using battens and screws to help join the slabs and resist bowing etc... The screws will be bored out where they join the underside of the slabs to allow for wood movement. Should joining the slabs with keys be the last thing I do to the top prior to sanding and finishing the top? This is my biggest project to date and don't want to screw anything up!

[Matt Day]

I too would be concerned about the butterflys cracking/breaking wile moving the top around. I would at least install the battens as well for additional structural integrity.

I've worked with a large top before but each board was edge glued, so I'm curious to hear answers from others on your situation. Beautiful wood by the way!

[Jamie Buxton]

The keys seem to me to be a little puny to hold those big slabs together while you're flipping the top around in the shop. You could screw temporary 2x4 reinforcements on to the under side of the table where the slabs will sit on the base. That way, the screw holes will be invisible in the finished product.

[David Nelson1]

Interesting project. I'll be keeping an eye for your progress. Good luck and looking great so far.

[Steve Kohn]

The keys seem to me to be a little puny to hold those big slabs together while you're flipping the top around in the shop. You could screw temporary 2x4 reinforcements on to the under side of the table where the slabs will sit on the base. That way, the screw holes will be invisible in the finished product.

You could do the same approach with a partial sheet of 3/4 plywood screwed to the bottom. That's what I would do.

[Timothy Juvenal]

I also completed a similar book-matched live edge slab trestle table a few weeks ago.

IMO, the 5 butterflys will have little structural significance, relative to the size and weight of the slabs, and should be considered purely decorative.

I would make the top members of the trestle ends heavy enough to serve as the battens that hold the two top sections in place, install them first, then flip the table over and add the butterflys. The leg tennons could be attached to the battens/trestle tops with removable pins, allowing the table to be knocked down for transport.

Timothy

[William Hamilton]

I think temporary supports is the direction I am going in. Once I plan my cuts for the inside sapwood and get that lined up and make those cuts, I'll place my .25" spacers in place between the slabs down the middle and then screw in the temporary supports. The supports will stay in place right up until actual assembly I think. I'm going to place them just inside of where the post assembly and battens will join the top. That way they're far enough to the ends of the slabs to provide ample support. I'll probably put one or two towards the middle for good measure. I'll just have to be sure not to place them where any butterfly keys are planned, otherwise I could be in for a surprise when routing those out.
It's funny, when dealing with wood like this I tend to not want to make any unnecessary holes in it. But really, the only time anyone will see the underside of the table is when they drop a fork. Well, who knows? hahaha.. knowing me I'll plug the holes.