Router table top issue?

[rafezetter]

I bought a secondhand UKJ router table top recently - it's birch ply and about 25mm thick laminated both sides with melamine - and although it's otherwise perfect I noticed yesterday when fitting it to my new workbench that it's crowned; turning it over and measuring from the underside against a veritas straight edge, the gap is 0.65mm using feeler gauges.

How much of a problem is this or should I make a framework for it to be fixed to underneath? I've got a clearance of 40mm just over, is this deep enough if done in hardwood alone to pull it (and keep it) flat? I've also got some lengths of thin (2mm) angled steel I could attach to the wood to reinforce it, or 5mm thick lengths of perforated flat bar 1m long.

Advice appreciated.

 

[sunnybob]

0.6 mm deflection over the length of the table (dont know how long the table is mind) is not very much at all.

It depends completely on your projected use of the table. If youre going to be making furniture sized mouldings, you will never find that amount of movement.
If youre planning to make tiny model engineering parts, you might.
Does the weight of the router pull it back into flat?
If youre making a base for it I would suggest you make allowances for it to "sag" back down.

I got fed up with Kreg plates because they sagged more than that across the 12" router plate. Making small mouldings it became obvious that wood was dipping up and down as it traversed the plate. But I made a router table for a local wood yard using one of the saggy plates, and they are well pleased with it for making 12 foot long mouldings.

 

[Mrs C]

Mine isn’t flat and while it’s ok for a lot of things I got thoroughly fed up when trying to cut the groves for kitchen door frames. I gave up in the end and found a friend with a spindle moulder!

 

[rafezetter]

Thanks for the replies, the distance is 400mm from the central router bit point to edge. I had thought about the router weight, but it's not affecting it as far as I can see.

The problem is it's being used as a flip up / down style router top so for the majority of the time the top will be hanging down instead of flat giving it little chance to flatten out.

Using some box beam steel lengths and g-clamps I can crank it back flat, but won't be able to do this once it's attached to the workbench via big hinges.

My concern is I've got some door detail moulding upcoming and while yes I could buy it - why do that if I've just shelled out £250 for the top, router and associated accessories.

 

[sunnybob]

At 250 quid second hand what was the new price? :shock:

How old is it and how used is it?
Axminster have superb customer relations, they might be able to help replace it.

 

[rafezetter]

Sorry Sunny - didn't see this reply - £250 was all in - Dewalt router (with iffy speed controller fixed for about £6) set of trend bits, the larger UKJ top (new £180), musclechuck, several other router bits, and the matching UKJ split fence sytem for the table (£120 odd new). Oh and the addon "router top access height adjust system" mechanism for the router.

So the £250 was a bit of a steal really, but I checked and he was happy with that, but I did bung in an extra £20 for a bag of other bit n bobs.

I've contacted Aximster about the top, still awaiting a reply and might take a trip as it's not that far away from Bristol, to get it swapped.

 

[sunnybob]

good bargain, worth making the extra effort to get it right.