Stable Wood For Flat Reference...

[darita]

I'm looking for a stable harder wood to use as a flat reference for gluing up table saw sled fences.  I'm pretty sure maple would be a good one, but it's pretty expensive, so I'd rather use something that is a little less $.  The reference slab will likely be a glue up of 3/4" boards to form a 4"x6"x30" slab. 
Also, how long do you think the slab will remain flat before having to be rejointed?

 

[sgryd]

Have you considered gluing two MDF sheets on a grid of wood-strips? I don't know the english word. Is is honeycomb? I think there is an old article about this at www.thewoodwhisperer.com/. You can probably find a hole lot of articles and videos on this. I know I have seen such a glue up table in one of Paul-Marcels videos, but I don't know if he has a video on building it www.halfinchshy.com.

//Michael

 

[mouppe]

I think Michael is referring to a torsion box.

I'd use maple myself, beech or birch. Beech is a traditional choice in the UK for making workbenches, hand planes etc. Here in Canada, maple is a common wood for workbenches as it is cheap, hard and quite stable. I true up my 6' bench once a year or so, and it requires less work each time. Now I have the process down to twenty minutes or so.

I'm not sure I understand why you are making a reference surface, truing it up and then gluing something based off it rather than just truing up the glued slab?