I think most readers would probably know that table tennis tables are supposed to have the basic dimensions of a rectangle 2.74m long, 1.525m wide, and 76cm above the floor. But did you know that the table you are playing on could actually be anywhere from 2.735m to 2.745m long and still be considered legal by the ITTF? Or that a diagonal corner to corner warping of up to 3mm in the playing surface is considered legal, provided it is not visible to the naked eye?

Interesting Table Tennis Table Facts

Don't believe me? Then check out the ITTF's Technical Leaflet T1 - The Table (546KB). It's about 19 pages long, and a bit technical at times, but it's full of interesting little facts and tidbits like the ones above.
For those of you who can't be bothered wading through the verbiage, here's a summary of the bits I found interesting in the document.

• Concrete tables are not approved for international play. Shame really.
• For general use, the tabletop board may be made of any continuous material, so anything goes - such as plywood, particle board, metal, plastic etc. But for major tournaments only wood or wooden derivates are allowed.
• The length of the table is allowed to be inside the range of 2.735m to 2.745m, while the width of the table is allowed to be within the range of 1.522m to 1.528m, and the height of the table can be within 0.757m to 0.763m. So the next time you just miss the edge of the table, it might not be you!
• The two table halves can be up to 2mm out of alignment when the table is set up, instead of lining up perfectly. Watch out for sneaky opponents offsetting the tables when setting up!

• Using a rigid straight-edged surveyor's staff of around 2m long from diagonal corner to corner, the biggest gap allowed is up to 3mm. But even so, smaller gaps are not allowed if they are visible to the naked eye - although they don't say whose naked eye - the referee, the umpires, or the players?
• ITTF approved tables must be blue or green, but they do mention that since around 8% of Caucasian males suffer from red/green color blindness (they don't mention females, but it is about 0.5% of Caucasian females, in case you were wondering), then blue is a better color to use in conjunction with the red floors recommended by the ITTF.
• You should not be able to distinguish the shape of a light-source in the reflection from a table surface.
• The table finishes should not transfer surface pigment on to the ball. I don't know about you, but I've played on a number of ITTF approved tables that mark the ball with the table color.
• You should not be able to use your fingers to feel a difference in level between the white lines on the table and the rest of the playing surface.
• The coefficient of friction between the ball and the table should not be greater than 0.6. If you want to know how that is measured, go check out page 7. I can't do it justice here. I think dog sleds are involved though. ;)
• A gap of up to 10mm is allowed between the centre line and the endline, and a gap of up to 50mm between the centre line and the net. I don't know why manufacturers can't complete the lines. Perhaps there is a world-wide shortage of white paint?
• The ball must rebound to a height of 230-260mm when dropped from a height of 300mm. The ball must bounce within an average range of 5mm, so that doesn't mean that a particular table can have a ball bouncing only 230mm in some parts and 260mm in others. It does mean, however, that some tables can be much bouncier than others (e.g. an average bounce of 255mm for one table compared to an average bounce of 230mm for another), and still be legal. The rest of the bounce measuring system made my eyes glaze over, so if you're into that sort of thing, you're on your own.
• The undercarriage may carry the ITTF logo but shall not carry any advertisements. Maybe there's a big problem with people crawling under tables to check out the ads?
• The undercarriage should not be white or flourescent, and should not reflect light upwards, in case players or spectators are dazzled by the table instead of the play. But those strange glowing undercarriages that I've seen on table tennis videos must be OK - I can't see how a table that looks like it is about to lift off in UFO fashion could possibly be distracting to anyone!
• Tables for wheelchair play should have their end legs inset by 40cm, instead of the 15cm inset for standard tables. This is to give the wheelchair players more room to drive the wheelchair under the table.

Conclusion

So there you have it, an assortment of facts about table tennis tables that I certainly wasn't fully aware of. Some are sensible, some are strange, and some are way out there, but all are part of the ITTF's rulings on table tennis tables. Who'd have thought?