If you can't be bothered to buy one of those expensive satnav/phone brackets/holders for the steering stem, try this
Get yourself the internals from a handlebar
Chop off the end and get some washers, a long m6 bolt with the head cut off, a spacer and re-use the rubber grommets, but change which end they are on
Fit together like this. The 2 lower washers fit snug inside the stem, the larger one stops the whole lot slipping down the tube
The spacer makes sure the rubber grommet is low in the stem and not liable to squeeze up out of the top
Slot it in and tighten it up
You can now fit any bracket you choose/make
This phone holder was pop riveted onto the bracket and then the rivets flattened with a hammer
Works a treat
Enjoy
