Joining boards, a D'oh moment

[burraboy]

Years ago I bought one of those Z shaped T&G router bits for joining narrow boards together into something wider, (mainly reclaimed pine pallet slats for shelves etc). It was always a problem getting the bit centered properly on the mid line of the side of the board and I invariably finished up with steps between each board that needed extra thicknessing to get rid of.
Then the D'oh moment, the light came on! I didn't need to set the bit to halfway at all! You set the bit somewhere about half way, it really doesn't matter where, and do one side of all the boards. When it comes to the other side you reset the bit visually, using the profile on the already cut pieces to match the router profile to give a near enough perfect match. Minimal thicknessing required.
I bet you all knew that anyway.

[munruben]

Of course we knew that. Another way to find centre of the edge of a board is to measure the thickness of the timber and mark it at the centre, then place one of those pointed router bits in your router, you know the ones that make a V groove. (Router switced off of course) and then adjust your fence so the bit pinpoints the exact centre of the board where your line marked the board. After you have made the fence adjustments, you can then replace the router bit with the bit you need to make you slot or groove in the board and it will route exactly in the centre of your board. Simple eh? I bet you knew that too.

[burraboy]

I'm confused John, are you talking about the centre of the edge, or the centre of a face? It is the depth adjustment of the bit that I found was the problem when working on edges, not the fence. Change the bit and you throw out all your depth adjustment. For face work, I tend not to use a fence, I made up a set of spacers for each different bit profile and use the spacers to set up a straight edge clamped to the job and work from that.

[munruben]

Sorry if I confused you, I have a habit of doing that. I was referring to locating the centre of the edge of a board.