alexnharvey wrote:Check the bolt size carefully, stem bolts are sometimes m7 which I think you will have to order from a specialist bike supplier.
yes but M7x1 screws are rarely (never?) found in sets of four on a faceplate; they more often travel in pairs only.
OP's stem looks to have M5x0.8mm screws in it. If these are like ones I have seen before then they will
a) have a head diameter that is smaller than is normal for an M5 caphead (so screwfix etc capheads won't fit unless modified)
b) be of 10.9 persuasion (thus any common stainless or titanium screw would be a step down in strength) and
c) have a built in captive washer under the head. This will again be of a non-standard diameter and
d) the screw will go rusty rather easily; first in the socket presumably because the plating is thinnest here.
They will probably also have a maker's mark in the bottom of the socket; in lieu of standardised marking this allows the screws (and their strength grade) to be identified. You can see the maker's mark in the photo below; the cable pinch bolt at the end of one arm is so marked ('K'), and so are the boss bolts ('T').