King Bed Headboard, Part 2: Working With Long Stock

Last week I wrote about designing the headboard.  The design includes two rails that, when tenons are included, are 76 or 77" long and 8" wide.  These are the longest (non-plywood) components I've ever worked with on a project.

The headboard design

While I tried to pick out boards that were as straight as possible, there was a bit of twist in both rails and a little bow in one of them.  These 5/4 boards had been "skip-planed" at the lumber store, so they were really about 1 1/8" to start.  So what started out as 5/4 boards ended up just under 1".  That's not too bad, considering my original plan was to use 1" thick material for the rails.  But after thinking about this a while and looking at the stock, I realized I should have shot for a 1 1/4" finished thickness, maybe even 1 1/2".

Anyway, working with these long boards is challenging.  I don't have a straightedge anywhere near long enough to mark a line to rip lengthwise, so at first I used a chalk line.

Chalk line marking the width

On the next board I just used a string, pulled tight from one end to the other and marked with pencil every couple of feet.  Connecting those marks with a metal straightedge gave me a good line to cut to.  For most of the ripping I do, I secure the board vertically in the vise.  But these boards were so long that the vise was impractical.  I hardly ever use the saw bench I made years ago, but it really came in handy for this.

My workbench is 58" long, almost 20" shorter than these boards.  Face planing wasn't too tough.  I used a bench dog as a planing stop when planing the far end.  When planing the near end, I overhung the board past the left end of the bench and clamped it in place.

When testing for twist, I used 5 or 6 locations along the length of the board.  This cherry planed very nicely and I was able to get the twist out fairly easily.  However, the top rail still has a little bow in it (less than 1/8") that I hope doesn't interfere with how the project comes together.

I've generated three 13-gallon bags of shavings with all the planing for this project.
This is just one of MANY piles.

The photo below shows the setup for planing an edge.  The left side of the board is held in the front vise and the right side is held to the bench with a holdfast.

A long board affixed to the workbench for edge planing

But my front vise sticks out from the front of my bench by about 1 1/2", so I use an L-shaped piece as a spacer so I can clamp the board against the bench.  The short leg of the "L" hangs down the front of the bench.

An overhead view of the spacer that allows me to clamp the board to the bench

In the design for this headboard, the upper and lower rails are separated by 11 vertical slats that will be connected to the rails via stub tenons in shallow mortises.  Because of that I needed the lower edge of the upper rail and the upper edge of the lower rail to be absolutely straight.

But my longest straightedge is only 24" long

I experimented with a string to see if I could monitor straightness.

String starting at one end, stretched to the other end ...

... and tried to see if the gap between string and edge could tell me if the edge had a hollow

Well, it was too tough to tell if the space between string and edge changed along the board's length, so I canned that idea.

I planed the edges as straight as I could and they looked perfect all along their length based on testing with the metal straightedge.  But when I stacked the two rails together, ...

Upper rail stacked on top of lower rail.
Can you see the light showing between them?

I planed the edges until I could no longer see any light.  I realized that they don't have to be perfectly straight.  They just both have to have the same "unstraightness".  Even if the two edges are not perfectly straight, as long as they mate perfectly the joints between the slats and rails should close up tightly when clamped together.

I knew there would be some challenges with a project this size.  But I love the challenge - it really makes you think about how to attack the problems that arise.