King Bed Headboard - Part 4: The Posts and Request for Input

The posts for the headboard were to be 3" wide and at least 2 1/2" thick.  I glued them up from 6/4 stock and ended up getting about 2 5/8" thickness.

A post blank glued and in the clamps

After squaring up the blanks and cutting to 51" length, I marked out the mortises.  The following pic shows the extents of the initially 8" wide upper rails, the upper extent of the rail after 3" will be cut away to create the curve on the upper rail, and the 1/2" shoulders.  The heavy line shows where the mortise will go; I haven't yet used a mortise gauge to mark the lateral extents of the mortises.

Mortise locations for the upper rails

Unfortunately I marked them on the wrong side.  I had oriented the posts so that the little bit of sap wood that was left after planing would be on the inside faces.  Fortunately I caught the error long before any mortises were to be cut.

D'oh!!

And here's them marked on the proper side, with mortise gauge lines delineating the lateral extents.

Mortises ready to be cut

These mortises were to be 2 1/4" deep and I wanted to keep them as square to that inside face as possible.

I find that orienting myself along the length of the workpiece helps me chop vertically

But I still use a square to verify

First one chopped, cleaned up and complete

This was quite a chore, so I ended up boring out the other three mortises.

Boring out most of the waste

Boring 2 1/4" deep took about 40-42 turns of the 5/16" bit and it got quite hot.  I kept a bowl of water nearby to cool the bit after each hole was bored.

Cooling down the bit

The lower rail will have a double tenon, so the mortise is 7 inches long.  The middle 1" will be only 1/2" deep, but the rest will be 2 1/4" deep.  So I cut the two deeper parts first and then joined them using a saw and 3/8" chisel.

Double mortises done, but center section not yet removed

Used a saw for the sidewalls of the middle part and chisel to remove the waste and level the bottom

I made the mortises this way to help me get the 2 1/4" deep end walls next to the central section as vertical as possible and to get those end walls at the marked location.  If I had chopped/drilled out the center section while I was mortising the two deep sections it would have been harder to get those walls perfectly positioned.

If any of you have read this far, it's time for audience participation.  I'm getting closer to glue-up and have been giving it a lot of thought.  The 78" total length of this headboard is far longer than any clamps I have.  I've thought about ganging clamps together to span that length, but it's really tough to do that by myself.  So I'm thinking about using the draw-boring technique.  I've done this before (maybe only once or twice) but never in cherry wood.  So I did an experiment with some scrap that was about the same thickness as my long rails (just under 1").

Chopped a mortise, prepared a tenon, drilled some holes and made some pegs

Offset the holes in the tenon by about 1/16" from the holes in the mortise

Tapped in the cherry pegs to draw the joint VERY tight

Front side (pegs entered here) after clean-up

Back side after clean-up - there's a tiny crack extending from one peg-hole to the other

In my headboard, I'll place two pegs in the 4" wide mortise/tenon of the upper rail, but the two pegs won't be anywhere near as close to each other as in the above test piece.  The lower rail with twin 3" wide mortises/tenons will have one peg per tenon.

So, here are my questions.  First, does anybody have experience with draw-boring in cherry?  Cherry can be a bit brittle and I'm just a little concerned.  I know I can mitigate cracking like I got in my test joint by off-setting the holes so they don't lie along the same grain lines, but I don't like the look it gives.  Any my holes for the headboard m&t joints will be much farther apart.

Second, I'm making the pegs out of cherry also.  While I'm making them from as straight-grained stock as I can, do I need to worry about them breaking apart from the hammer blows used to drive them in (that wasn't a problem in my test, but my test piece was thinner)?

Finally, the headboard posts (the mortised component) are 2 5/8" thick, so the pegs will be going through more material than in my test piece.  Should I be worried?

Any advice would be helpful.