Strange Problem Jointing Curly Maple

[Dustin Brown]

So I got my shop all setup and decided to do a few tests runs on everything. I took a piece of 1x8 pine and jointed the face flat, then the edge, then on to the planer and tablesaw. I ended up with a perfectly flat square board without any issues.

Then I decided to do a rough cut curly maple board 3/4"x8"x26". I started with the flattest side and proceeded to make very light passes to save as much material as possible. As I progressed and started getting the face close to flat I noticed the last 6" or so just wasn't leveling off with the rest of the board. This is where it gets weird for me. The face I'm jointing is almost flat except for the last 6" which bows upward very slightly about 1/16-1/32. When I flip the board over I would expect to see the board cup slightly right? Nope, now the last 6" or so bows upward at least 1/16". The board is almost the same thickness all the way down so that's not it.

Any ideas what is going on? I'm completely lost on this. Something about heavily figured maple I don't know?

[Robert Chapman]

So if both sides of the same end bow up that means that the board is narrower at the end - not the same thickness. I work with curly maple a lot and have not found it to be uniquely difficult to machine. Sounds like you just have a board that tapers.

[Myk Rian]

How are you jointing it? Keep pressure on the outfeed end, and make sure the knives are level with the outfeed table.
After jointing, having a board that is thicker on one end is not uncommon.

[doug faist]

I'm wondering if this is a technique problem rather than a wood problem. If pressure is applied to the in-feed table throughout the pass, you may get a taper at the end. Try pressure on the out-feed table at the end of the cut.

My experience with curly maple, admittedly limited, has been that it's a pretty easy wood to work.

Just my $.02.
Doug

[Dustin Brown]

I've measured the board and is almost the same thickness all the way down. I keep pressure off the infeed table I've got a good 6" or so on the outfeed so I make sure I don't flex the board. Maybe it is something I'm overlooking. I'll try again tomorrow and see what happens.

[Rick Fisher]

I have had that experience and its usually that the board is not straight.. Turn it around and it should be the same .. It may appear straight, but isn't ..