I bought a big torque wrench of ebay. It takes a ⅜" socket, so I also got a ⅜" to ¼" socket adapter, and then a ¼" socket to ¼" hex bit adapter... Then in front of my bike when I went to use it the first time. I read the setting I needed (6Nm), looked at the scale on the torque wrench, and then realised I'd bought a wrench in Imperial units...
*headdesk*
Not deterred, I went to the googles and asked for a conversion, between units, only to then find that the minimum setting on the wrench was higher than the 5Nm I was trying to achieve.
On the plus side it has a lovely heft and I'm sure can serve dual use for hand to hand combat...
J