My stem faceplate should be fastened to 6n/m, whereas the handlebars say 5n/m max. I’ve tightened to 5 and the bars slip. I’m reticent to tighten to 6 as it exceeds the recommendation. Any thoughts?

What stem/bars?, if carbon bars use grip paste. Some stems need the stem faceplate pulled up parallel to the stem (thomson etc), easton and some others need the top two bolts tightened right up to the recommended torque thus mating the stem faceplate to the stem then the bottom two torqued up.

Otherwise try 6nm, unless you have a particularly accurate low NM rated torque wrench then you will have a +/- 10% discrepancy with the regard to the actual torque at the lower and upper range so what you may think is 5nm, may in fact be less/more.

Thanks for the advice

It’s on my road bike – Look C-Stem and Cinelli NeoMorphe XL Carbon bars

For a stem like that paired with the carbon bars i’d definitely use a squidge of carbon paste – it’s not your average/run of the mill carbon stem so take it easy wi the torque wrench and use either 242 threadlock or anti-seize paste on the threads depending on what Look recommends. Most bike shops will have small sachets of carbon assembly paste or tubes of it, either buy a sachet/tube or ask for a squidge of it in a wee plastic baggie depending on how well you know the shop/mechanics.

Somafunk – will do. Cheers