Tongue & groove floorboard repair-size of tongue?

acrobat, Jul 2, 10:02pm
Hi, I need to repair a friends broken floorboards in an internal room doorway. Currently there is just some MDF in place. Upto it are pine floorboards. They look to be 90mm wide. I believe the thickness is 20mm. Can anyone tell me the standard tongue and groove size I need to make to fit? I would like to pre-make these at my work shed and then take them and insert into place rather than taking a heap of tools over and create a mess there. It's only a few boards so if I can pre-make them it will save a lot of time and effort and hopefully I can just remove the MDF and insert the new boards in place easily.

budgel, Jul 3, 2:40am
There is no standard as such. Each timber company had their own sets of knives.

morrisjvan, Jul 3, 6:48am
''they look to be 90mm'' and ''I believe the thickness is 20mm'' Do you not have a rule ? why don't you just guess the tongue size as well?

dastedly, Dec 1, 5:09pm
In the days when T&G was machined there were no thing in mm it was just in Ins .Most was 1/4 ins off the full Ins size .