Marble,Granite tiles

[rosinante]

Hi all, I am trying to make a router table that stays flat, are marble,granite tiles, 1 flat? 2 parallel in thickness,? My garage cum workshop varies wildly in humidity and temperature so any thing that is at all hygroscopic wriggles around , I have just made a top for a router table and even though I glued up while weighted down on my cast iron table saw it still came up with a slight bow.
So I thought maybe a 400 mm square tile might be an option, cutting the top hole may be a challenge though.
Any other ideas or suggestions welcome,
Cheers
Chris

 

[Parm]

Some 18mm ply with a Formica should be good enough. That's what I have and it stays flat

 

[slim_boy_fat]

2mm or 3mm steel sheet cut to size?

 

[Cobbler]

Some 18mm ply with a Formica should be good enough. That's what I have and it stays flat

You want Formica both sides to balance it, else there is a chance it will bow. The wood expands & the Formica doesn't.

 

[Parm]

That's interesting, I use a piece of marine ply that's screwed into a 3x3 frame then laminated, haven't really noticed it warping

 

[bigegg]

6mm aluminium plate?
I had a piece of perspex 450x450x10mm you could have had for 20 quid - sold it now tho...

 

[rosinante]

I have piece of ally plate big enough but again it isn't flat, also tried paxolin again not flat, currently have 10mm. Paxolin glued to 18mm mdf, started off reasonable but now has 1 mm bow along the length, I suppose a milled flat plate 12mm or so thick would do it but I suspect the cost would be prohibitive for a piece big enough,don't even know if it is sold milled flat. Hence the tile idea,
Thanks
Chris

 

[bigegg]

MDF is THE worst stuff to use - especially laminated on one side.
I've used a piece of kitchen worktop on my portable jobsite router - that gets battered about regularly, and stays flat enough.
Why do you need such flatness btw?
as long as you use holddowns near the cutter, then any timber should conform to the 1mm?
If you find some timber that doesn't - use that for your table top!

edit: a piece of granite worktop (headstone?) might work - get it machined at the suppliers?
Or a cast concrete top? (google cast concrete worktop)

 

[slim_boy_fat]

Something like this? http://www.manomano.co.uk/wood-shap...er_id=537135&gclid=CLrW0emV9coCFUrlwgod6skGUg [other makes are available ]

I have a similar one and it does all I need fine.

 

[rosinante]

Hi ,thanks for replies, I guess that I am being a little anal about the flatness but I would like to have a reliable surface to help keep things square etc, I am not able to justify the price of a commercial item esp cast iron and I suspect the cheapo units will be no better than the one I have built so far.
It seems that "flatness " is harder to achieve and maintain than squareness and level etc,
cheers
Chris

 

[DrDeAtH]

Some high pressure lamate, like what is used for worktop jigs would probably be ideal for a router table top